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UNCLASSIFIED i" 20
WAR DEPARTMENT
ARMY AIR FORCE
FTETTl MANUAL
J? xxuLjxJ irxxxll UAIj
TACTICS AND TECHNIQUE OF
AIR RECONNAISSANCE
AND OBSERVATION
April 20, 1942
REGRADED UNCLASSIFIED BY
authors of D00 DIR. 5200. 1 R
Lt, Arv\e,\oer-<
FM 1-20
ARMY AIR FORCE
FIELD MANUAL
TACTICS AND TECHNIQUE OF
AIR RECONNAISSANCE
AND OBSERVATION
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1942
WAR DEPARTMENT,
Washington, D. C, April 20, 1942.
FM 1-20, Army Air Force Field Manual, Tactics and Tech-
nique of Air Reconnaissance and Observation, is published
for the information and guidance of all concerned.
[A. G. 061.11 (2-17-42.).]
By order op the Secretary of War:
G. C. MARSHALL,
Chief of Staff.
Official:
J. A. ULIO,
Major General,
The Adjutant General.
Distribution:
R and H 1-7, 17 (6) ; Bn 1 (8), 17 (5) ; IBn 7 (5) ; IC 7,
11 (5).
(For explanation of symbols see FM 21-6.)
TABLE OP CONTENTS
Chapter 1. General. Paragraphs Page
Section I. Scope and definitions 1-2 1
n. Tactical functions 3-7 2
III. Factors affecting air reconnaissance
and observation 8-15 3
IV. Operations 16-28 9
Chapter 2. Air reconnaissance for air force aviation.
Section I. General 29-30 17
II. Securing information 31-47 17
III. Support of air attack 48-53 38
Chapter 3. Air reconnaissance and observation for
ground forces.
Section I. General 54-55 42
II. Distant and close reconnaissance
missions 56-58 42
HI. Battle of reconnaissance missions 59-67 44
IV. Liaison missions 68-70 49
V. Adjustment of fire for mobile artil-
lery 71-76 50
VI. Cooperation with Cavalry 77-81 52
VII. Cooperation with seacoast artillery. 82-89 55
VIII. Cooperation with armored and mo-
torized forces 90-94 58
Index ■ 63
hi
qimmmt&ED fm 1-20
ARMY AIR FORCE FIELD MANUAL
TACTICS AND TECHNIQUE
OP
AIR RECONNAISSANCE AND OBSERVATION
(This manual supersedes FM 1-20, February 10, 1941, including
Training Circular No. 20, War Department, 1942.)
CHAPTER 1
GENERAL
Paragraphs
Section I. Scope and definitions 1- 2
II. Tactical functions 3- 7
in. Factors affecting air reconnaissance and observa-
tion a-15
IV. Operations 16-28
Section I
SCOPE AND DEFINITIONS
■ 1. Scope. — This manual contains instructions relative to
the tactics and technique involved in air reconnaissance and
observation and in the various types of air reconnaissance and
observation missions executed in support of air and ground
forces.
D 2. Definitions. — a. Air observation and reconnaissance. —
The gaining of information through visual and photographic
means carried in aircraft.
b. Reconnaissance mission. — A flight for the purpose of ob-
taining information by visual or photographic means. Re-
connaissance missions are classified as distant, close, and
battle.
c. Artillery mission. — A flight for the purpose of locating
artillery targets, adjusting artillery fire, reporting the effect
of fire, or for the surveillance of scheduled artillery fire and
enemy activity.
d. Liaison mission. — A flight to transmit information or in-
structions or otherwise to maintain contact between a com-
mander and other commanders or organizations.
e. Air area. — The area within which a commander is
charged with responsibility for air reconnaissance and ob-
servation.
1
3-6
ARMY AIR FORCE FIELD MANUAL
Section n
TACTICAL FUNCTIONS
■ 3. General. — Air reconnaissance and observation opera-
tions are characterized by wide range and great depth, by the
provision for taking air photographs, and by the rapidity with
which information is obtained and transmitted. They are
limited by poor visibility, bad weather, antiaircraft fire, and
the opposition of hostile combat aviation.
■ 4. Missions. — Reconnaissance and observation aviation
units are organized, equipped, and trained- to conduct air
reconnaissance, observe fire, gain military information by
visual and photographic means, transmit instructions and
reports in accordance with the orders of the units to which
assigned or attached, and to furnish aerial photographs for
use as photomaps.
■ 5. Functions. — Air reconnaissance and observation mis-
sions include operations involving search, patrol, tracking,
contact, and adjustment of artillery fire, as well as liaison
and courier tasks.
■ 6. Characteristics of Reconnaissance and Observation
Aircraft. — a. Air force reconnaissance aviation is equipped
with airplanes capable of conducting the long-range strategic
and striking force reconnaissance over land and sea. The
airplanes may be specially equipped bombardment types
which are also capable of use for air attack.
b. Observation aviation is characterized by equipment de-
signed for wide angle vision, and to meet the needs of ground
units for gaining military information from the air by visual
and photographic means. Its speed and performance are
suitable to the purpose for which it is intended and are such
as to permit reconnaissance of an extensive area in a short
period of time; its communication facilities permit the rapid
transmission of reports to the using agencies. Observation
aviation is equipped with —
(1) High performance airplanes of high speed and suf-
ficient range to penetrate hostile territory, and equipped for
photographic or visual reconnaissance.
(2) Light, low performance airplanes designed for artil-
lery observation missions and liaison missions in rear of
friendly front lines.
2
AIR RECONNAISSANCE AND OBSERVATION
7-8
■ 7. Reconnaissance by Combat Aviation. — The gaining of
information by units of combat aviation is usually incident
to the accomplishment of their principal mission of air com-
bat. Aircraft engaged on air attack missions may be routed
over specified areas for the purpose of gaining information
concerning a particular activity or installation within such
area. When air reconnaissance and air attack are combined
in one operation, the primary task is air attack unless other-
wise indicated.
Section III
FACTORS AFFECTING AIR RECONNAISSANCE AND
OBSERVATION
■ 8. General. — a. (1) Ability to see is essential to the per-
formance of air reconnaissance and observation. Unless the
radius of visibility is sufficient to enable the observation crew
to locate the object, activity, or area to be observed
and to see it with sufficient distinctness to secure the
desired information, air reconnaissance and observation is
impracticable.
(2) Air reconnaissance and observation missions will be
unproductive if the enemy counterreconnaissance measures
deny access to the area or objective to be observed, or cause
the incapacitat'.on of the observation crew or the destruc-
tion of the airplane prior to the time that information
secured is transmitted.
b. Among the factors affecting the ability to see are the
type and amount of illumination, the clarity of the atmos-
phere, the size or mass of the objective, the terrain character-
istics and ground covering, the angle of view, and the altitude
from which the observations are made.
c. Security is affected by the type and strength of the
hostile antiaircraft defenses; the performance characteris-
tics and defensibility of our equipment; the skill of the combat
crew in employing their defensive weapons, if intercepted,
and in avoiding detection and interception under the pre-
vailing weather and visibility conditions. Darkness, clouds,
and poor visibility conditions increase the difficulty of detec-
tion and interception by the enemy and thus contribute in
greater or lesser degree to security.
3
9
ARMY AIR FORCE FIELD MANUAL
■ 9. Illumination. — The illumination provided by the sun,
the moon, and the stars is termed "natural illumination."
That provided by flares, photographic flashlight bombs, and
similar means is termed "artificial illumination." Objectives
are said to be self-illuminated when they are illuminated by
fires or lights within them or nearby.
a. Sunlight. — (1) Sunlight affords the most satisfactory
illumination for air reconnaissance and observation. The
capabilities of daylight reconnaissance and observation are
limited by adverse weather conditions. The extent to which
adverse weather conditions interfere with reconnaissance and
observation during daylight depends on the characteristics of
the flying equipment, the familiarity of the flying personnel
with the terrain to be traversed, the flying and air observation
experience of the crew, the nature of the information required,
and the location and character of the objective.
(2) Daylight with favorable visibility conditions permits
the rapid reconnoitering of large areas, facilitates aerial
photography, and provides the most favorable conditions for
a detailed examination of the ground. For that reason it may
be expected that troop and supply movements will be made
at night whenever practicable and that if daylight move-
ments are necessary the enemy will take all possible steps
to prevent their discovery.
(3) Daylight favors the detection, interception, and at-
tack of reconnaissance and observation airplanes. Daylight
reconnaissance and observation of defended areas may be im-
possible, especially if deep penetration of enemy territory is
required.
b. Night. — (1) Darkness imposes a considerable handicap
on air reconnaissance and observation. Adverse weather and
visibility conditions, such as low clouds, snow, rain, dust and
smoke, that merely reduce the effectiveness or ease of daylight
operations may completely bar night operations. Night sea
search is unreliable. Night reconnaissance is most productive
in the examination of previously located fixed objectives,
routes of communication, and small areas that can be located
with sufficient accuracy at night to permit the use of artificial
illumination.
(2) While general area reconnaissance is impracticable
at night, bright moonlight affords sufficient illumination for
4
AIR RECONNAISSANCE AND OBSERVATION
9-10
the observer to detect larger objects and, under certain con-
ditions, small bodies of troops and single vehicles In the
open or on light-colored roads. The general characteristics
of the terrain (whether wooded or open) , prominent coastal
indentations, lakes, rivers, highways, and railroads ordinarily
can be distinguished by moonlight with clear visibility. How-
ever, artificial illumination is necessary for the detailed
examination of the ground.
(3) Night aerial photography with artificial illumination
produces excellent results under good visibility conditions.
The area covered by a single photograph, however, is limited,
hence great accuracy is necessary in the location of the ob-
jective. Technical improvements are expected to increase
the altitude from which night photographs can be taken
successfully, with a corresponding increase in the area covered
by a single photograph.
■ 10. Weather. — a. Weather is a factor primarily because of
its effect on visibility and on flight. Severe atmospheric dis-
turbances, such as thunderstorms and line squalls, constitute
a practical bar to air reconnaissance and observation opera-
tions within the area they cover.
b. Bain and falling snow affect air reconnaissance and ob-
servation to the extent that they restrict visibility. Fre-
quently, however, surface activity will be disclosed by the
trampling, soiling, or melting of snow. Rain and falling
snow adversely affect radio reception in aircraft; if sufficiently
heavy they render reception impossible.
c. Areas covered by fog are completely screened from the
eye or the camera of the air observer. At night open lights
and fires may be seen through thin fog.
d. Air observation of surface objectives and activity through
more than thinly scattered clouds is impossible. Clouds ef-
fectively block vision. It is therefore generally necessary to
observe from beneath the lowest layer of clouds. When the
nature of the mission permits the use of clouds for conceal-
ment, the detection and interception problem of the enemy
is rendered more difficult.
e. Haze, dust, and smoke restrict the radius of visibility.
If present to any great extent, either singly or in combination,
they may render air reconnaissance and observation unpro-
452263° — 42 2
5
10-12
ARMY AIR FORCE FIELD MANUAL
ductive. Haze, dust, and smoke are far more serious at night
than by day, and may completely bar night reconnaissance
and observation when present in quantities that during the
daytime would be classified as moderate.
■ 11. Visibility of Objectives. — Prominent terrain features,
such as mountains, lakes, and rivers; and large man-made
works, such as power dams, isolated large buildings, and cities
and towns, generally constitute the most distinguishable ob-
jectives. Within cities and towns, water front and railroad
installations, parks, and monumental type buildings stand out
prominently. Smoke and the dust raised by moving columns
can be seen for long distances in the daytime; lights and
fires are visible for great distances at night. The distance
from which troops, vehicle columns, and small supply estab-
lishments or installations can be seen is dependent, among
other things, on the degree of concentration or dispersion, the
terrain, the ground cover, the efforts made to secure conceal-
ment, and the angle of view. The air observer may miss
many important details, however, because of his rapid
movements and the necessity for watching the upper air
to guard against surprise by hostile pursuit aviation. The
observation team cannot function as an all-seeing eye that
minutely examines and reports on every detail in the sector
over which it flies. Visual reconnaissance of a specific area
or objective should be supplemented by photographs when
practicable. A well-camouflaged gun, not visible to the ob-
server, may be visible in a photograph or may cast a shadow
which, recorded by the camera, discloses the position of the
gun to an intelligence officer studying the photograph.
Stereoscopic photographs are especially valuable in the dis-
covery of details which are. not visible to an observer.
■ 12. Terrain Characteristics and Ground Cover. — Terrain
characteristics and ground cover are of importance to the
extent to which they conceal or defilade objectives and activi-
ties on the surface. Terrain features are of importance be-
cause of the manner in which they facilitate flight orientation,
both day and night. Prominent coastal indentations, large
lakes, and wide rivers are of material assistance in night
orientation. (The distance and altitude from which they can
be seen at night are dependent upon the amount of natural
6
AIR RECONNAISSANCE AND OBSERVATION 12-14
illumination and general visibility conditions.) Ground cover
is of importance because of the opportunity it presents for
concealment and for the employment of camouflage. Ve-
hicles, troops, and small supply facilities and installations dis-
persed in woods are difficult to see and, with proper camouflage
discipline, may remain undetected for an appreciable period
of time. The presence of troops may be disclosed by the
cutting of new paths, trails, or roads, by fire or smoke, and
by a general lightening of the appearance of the area. The
presence of vehicles may be disclosed by the disturbance of
the road shoulder at the point at which they left the road
and the crushing of the vegetation incident to their move-
. ment to their concealed position. The crushing of vegetation
incident to the movement of personnel and materiel shows
very plainly in night as well as day photographs.
■ 13. Angle of View. — In general, air reconnaissance and
observation is more effective when the line of sight is vertical
or nearly vertical, and becomes less effective as the line of
sight approaches the horizontal. Terrain features and
ground cover may defilade objects when the angle of view is
oblique, whereas they may be no bar to detection if the angle
of view is vertical or nearly so. For this reason the exami-
nation of broken or wooded areas to locate troops, vehicles,
and objects of low visibility generally must be accomplished
at low altitudes and will, therefore, take longer or require more
airplanes than would be the case in a flat area with no ground
cover. However, in wooded areas it is frequently possible
to secure good observation by an oblique view, and oblique
photographs taken under such conditions are often more
effective than vertical photographs.
■ 14. Altitude. — a. The altitude from which details on the
ground can be seen depends on the visibility and ground cover.
Under good visibility conditions during daylight, motor con-
voys, railway trains, and long marching columns can be seen
and their direction of movement ascertained from an altitude
of 10,000 feet. Small bodies of troops, not concealed in
trenches or fox holes, can be observed from 2,500 feet. At
1,500 feet the observer can follow the progress of an infantry
attack. At 1,000 feet he can determine whether trenches,
fox holes, or shell holes are occupied. To identify troops by
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14-15
ARMY AIR FORCE FIELD MANUAL
their uniform and equipment it is necessary to descend to
within 500 feet of the ground. When operating at extremely
low altitudes it will often be necessary for the observer to
make a number of trips over the same terrain to assure
himself that he has not missed some important details.
b. Sea search is facilitated by the lack of defilade. With
normal visibility, smoke can be seen from 18 to 25 miles. Ten
thousand feet is the most suitable altitude from which to
search for surface vessels, which, with clear atmosphere, can
be seen from 11 to 15 miles, depending on their size. Five
thousand feet is the best altitude when searching for subma-
rines on the surface. Prom this altitude they can be seen,
with clear atmosphere, from 5 to 8 miles depending on the
smoothness of the sea. One thousand feet is the best alti-
tude for sea search at night. Prom that altitude, with favor-
able visibility, smoke can be seen about 3 miles and surface
vessels from 2 to 3 miles, depending on their size.
c. The altitude above the terrain covered at which aerial
photographs are taken will influence the scale of the photo-
graphs. The camera used for photographic reconnaissance
should have a focal length that will give the desired scale
at the altitude at which it is planned to operate.
■ 15. Security. — a. Airplanes employed in the performance
of air reconnaissance and observation have the greatest free-
dom of action when operating singly. Airplanes operating
singly are particularly vulnerable to attack by hostile aircraft
and must resort to every reasonable means of avoiding dis-
covery and attack by hostile aviation.
b. Reconnaissance and observation aircraft operating in
formation have their maneuverability restricted. The re-
quirements of formation-keeping may seriously interfere with
the performance of the reconnaissance or observation mission.
Small formations of reconnaissance or observation airplanes
do not have sufficient defensive strength to cope with enemy
fighters in force. When the securing of vital information
requires the penetration of areas wherein enemy fighter avia-
tion is known to be operating, two or more airplanes may be
assigned to the same task in order to increase the likelihood
of at least one returning. When so assigned they operate in-
dependently. The presence of friendly fighter patrols may
8
AIR RECONNAISSANCE AND OBSERVATION 15-18
afford adequate protection against hostile aircraft in shallow
penetrations of enemy territory. Special support by escort
fighters may be required to carry out air reconnaissance or
observation missions in the presence of hostile fighter forces.
c. Darkness in itself affords a great measure of security be-
cause of the difficulty of locating airplanes at night and of
making interception after location has been accomplished.
When an objective in a defended area can be located at night
with sufficient accuracy to permit the use of flares, and when
such flares will provide adequate illumination, night recon-
naissance or observation is indicated.
d. Whenever practicable, reconnaissance and observation
aviation takes advantage of concurrent air operations in other
areas, which may serve to occupy or draw off hostile defensive
air elements.
Section IV
OPERATIONS
■ 16. General. — Air reconnaissance and observation opera-
tions are important to gain information or to facilitate com-
bat operations of other forces.
■ 17. Air Observation Teams. — Insofar as practicable each
air observation team (pilot and air observer) should remain
intact throughout any operations. Teamwork, which is an
essential factor in the conduct of war, is thus promoted.
Moreover, it is desirable that air observation teams should be
assigned the same type of mission throughout any operations,
if possible. By so doing the combat team idea is more nearly
carried out between the supporting and the supported units.
■ 18. Familiarity With Plans. — To insure the most intelli-
gent cooperation between the air observer and the supported
unit, the air observation team should be familiar with the
general scheme of maneuver of the supported forces and
with the details of every operation in which they may be
called upon to take part. The plan of employment of other
reconnaissance and observation units and of all air force
operations in the vicinity should be known to planning per-
sonnel to insure coordination and to allow the observation
units to take advantage of the fact that hostile fighters will
be attracted to the routes taken by friendly air forces.
9
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ARMY AIR FORCE FIELD MANUAL
■ 19. Familiarity With Terrain. — Pilots and observers en-
gaged in air reconnaissance and observation should be suffi-
ciently familiar with the terrain over which they operate to
maintain their orientation without too frequent diversion of
their attention to the study of a map while in flight. It is
especially important that they be familiar with the terrain
during the conduct of night reconnaissance missions, as many
of the landmarks that assist orientation in the daytime will
be indistinguishable at night. Accurate orientation is essen-
tial for the employment of artificial illumination and night
photography.
■ 20. Altitude. — o. No definite rule can be stated regarding
the altitude at which air reconnaissance and observation
missions are performed. The most suitable altitude depends
upon such factors as the mission, the character of hostile
fighter activities, the amount and effectiveness of hostile
antiaircraft fire, the performance characteristics of the air-
craft employed; the ceiling; visibility conditions, clouds, or
other weather conditions; the degree to which the aircraft
is camouflaged and its motor muffled; as well as the type and
details of the information to be obtained. During the conduct
of a single mission it may be necessary to operate at various
altitudes, that is, to cross the lines at the maximum altitude,
and to descend to within a few hundred feet at the objective
in order to obtain essential details. Photographic missions
usually are flown at greater altitudes than visual observation
missions. In general, the greater the detail required the
lower the altitude at which the objective must be examined.
Except for some photographic missions, including mapping
photographic missions, the choice of altitude should be left
entirely to the pilot and observer performing the mission.
They will fly at the altitude that will be most favorable for
obtaining the desired information and at the same time
expose them as little as possible to the chance of being shot
down.
b. Distant reconnaissance missions ordinarily are flown at
the maximum altitude permitted by atmospheric conditions
and the service ceiling of the airplanes employed.
c. Close reconnaissance missions ordinarily are flown at
that altitude which will provide the necessary detail without
a too serious compromise of security. When practicable, the
10
AIR RECONNAISSANCE AND OBSERVATION 20-21
maximum altitude is utilized for the approach and with-
drawal, the airplane descending to the altitude most suitable
for examining the objective when at or in the vicinity of the
objective.
d. (1) In the absence of effective fighter opposition, bat-
tle reconnaissance missions are flown at low or intermediate
altitudes. So long as the airplane remains over friendly
territory, the observation team is free to select the altitude
most favorable for air observation. When over enemy ter-
ritory the airplane must be kept above the effective range of
small-arms Are, about 2,500 to 3,000 feet. It will then be
within the effective altitude band of small-caliber antiair-
craft artillery. Decision as to whether to operate in that
band or go higher into the band of larger-caliber antiaircraft
artillery (above 4,500 feet) will be governed by the nature
of the information sought and the relative amount and effec-
tiveness of the two types of antiaircraft artillery.
(2) In the presence of effective hostile fighter aviation,
daylight battle reconnaissance missions are flown at extreme
altitude, observation being conducted from as deep within
friendly territory as possible.
■ 21. Night Operations. — Despite the difficulties of night
reconnaissance, an experienced air observer usually can ob-
tain valuable information. His success is based on his
knowledge of the appearance of things at night, what to look
for, and where to look for it. It is very difficult for the
enemy to carry on much activity at night without indica-
tions of it showing in some form, for example:
a. Columns. — On light-colored roads, columns are visible
in the form of dark irregular masses. Men walking in single
file on each side of the road are practically invisible on an
average night, but their presence may be disclosed by acci-
dental light or reflection from metallic equipment.
b. Bivouacs. — The location of bivouacs may be disclosed
by light, fire, or by visible smoke, especially during the early
part of the night. The ground in the vicinity of a bivouac
or encampment becomes lighter in appearance, and paths
may appear in a few days because of the trampling of the
vegetation.
e. Trains. — On clear nights, trains can be seen against
a contrasting background. Horse-drawn and motorized
11
21
ARMY AIR FORCE FIELD MANUAL
trains may be distinguished by the difference in their rates
of movement. The presence of a considerable number of
vehicles in a limited area may indicate the location of a
supply depot or dump.
d. Rail transportation. — Railroad trains ordinarily can be
seen from low altitudes on clear nights. On dark nights the
location of a railroad train may be indicated by the lights
on the rear of the train, by the glow in the cab of the engine
or the reflection on the smoke when the fire door is opened,
or by a shower of sparks from the smokestack. Railroad
stations may be located by platforms, the convergence of
roads, or by lights, particularly the red and green signal
lights.
e. Airdromes. — The discovery of airdromes at night ordi-
narily is difficult, unless hostile flying activity discloses their
location. On clear moonlight nights, airplanes taxying,
taking-off, or landing may be seen, and the presence of air-
craft on the ground may be noted. On dark nights activity
may be indicated by signal, boundary, range, or flood lights.
If the location of the airdrome is known, activity or prepara-
tions for activity may be discovered by the use of flares or
night photography.
/. Antiaircraft defenses. — Antiaircraft defenses, being eas-
ily concealed or camouflaged, are difficult to discover at night,
when not in action. Antiaircraft artillery in action is dis-
closed by the searchlight beams, and by the flashes of the
guns and machine guns, but it may be difficult to plot their
position accurately unless recognizable terrain features can
be seen.
g. Artillery. — Field artillery batteries may be hidden in
woods and ravines, and usually can be discovered at night
only when they are in action. The exact location of a single
gun may be difficult to determine, as the flash is of short
duration, but it often is possible to estimate very closely the
zone of batteries in action. The caliber of the guns fre-
quently may be determined by their rate of fire.
h. Front lines. — The opposing front lines usually are indi-
cated by rockets sent up at various intervals. An observer
who is thoroughly familiar with his sector can, by flying low,
identify the bursts of shells and the fire of rifles or machine
guns. A careful observer should, except under conditions of
12
AIR RECONNAISSANCE AND OBSERVATION
21-24
poor visibility, be able to detect heavy reinforcements mov-
ing into a given area. Information of such movements is
very important because they usually indicate an impending
attack.
■ 22. Accuracy of Reports. — It is essential that observers
exercise care In the preparation of their reports, in order that
the information gained may be accurately and completely
stated. An observer should report exactly what he saw, where
he saw it, and the time at which that particular observation
was made. Without all three factors, what, where, and when,
with regard to each item of information reported upon, the
missions may have been a waste of time. Special care must
be exercised in avoiding errors when reporting negative in-
formation. An observer may correctly state, for example,
that no troops were observed at a particular place at a specific
time. Because of the possibility of concealing troops from the
view of the air observer, a report that no troops were at that
place at the time of observation might be erroneous. When
enemy forces are seen, however, the report should include as
accurate an estimate as can be made of their strength, com-
position, disposition, and direction and rate of movement.
■ 23. Nature op Information. — The nature of the informa-
tion desired will affect both the time and the manner in
which air reconnaissance and observation is executed. Orders
for air reconnaissance and observation of defended areas
should, whenever practicable, call for information in the
simplest form which will meet the requirements of the situa-
tion and which at the same time will require the least exposure
of the airplane to enemy fire.
■ 24. Communication. — a. On close and distant reconnais-
sance missions, radio communication is necessary if the time
factor is important. However, the use of radio should be
kept to a minimum by reconnaissance airplanes deep in
enemy territory to reduce the probability of location and
tracking by means of radio goniometry. Long messages
should be dispatched in a series of short transmissions, with
sufficient interval between transmissions to enable the air-
plane appreciably to alter its position.
b. Radio is the most satisfactory method of communication
for artillery missions conducted by airplanes, but in the
452263°— 42 3 13
24-25
ARMY AIR FORCE FIELD MANUAL
event that radio cannot be used, acceptable results can be
secured from other means of air-ground communication, such
as wing signals, pyrotechnics, etc.
c. Two-way radio, and dropped messages, pick-up messages,
and panels provide the most satisfactory methods of com-
munication. Pyrotechnics, signal lamps, and other means of
communication are employed, if necessary, in accordance with
prearranged plans.
■ 25. Security. — a. (1) When the task of a reconnaissance
mission involves deep penetration of hostile territory, the
hours of darkness should be utilized to the maximum extent.
If the nature of the mission or other conditions preclude
night reconnaissance, the hours of darkness should be utilized
either for the approach or the withdrawal.
(2) Unfavorable weather conditions which do not definitely
preclude air reconnaissance may contribute to security if they
can be utilized. The opportunities afforded for concealment
by clouds during the approach and withdrawal, and while at
the objective, should be exploited to the utmost. Airplanes
on contact missions or engaged in tracking enemy surface
forces should withdraw into the clouds whenever practicable
upon completion of each examination of the objective, and
should utilize the clouds to cciver their successive approaches
to the objective. In the case of solid overcast conditions of
such a nature as to preclude over-the-clouds flight, a certain
amount of concealment can be obtained by flying just in the
clouds, emerging periodically if necessary to check position
or observe. Aircraft approaching an objective from the sun
are difficult to see, hence the up-sun approach should be
utilized whenever practicable.
b. (1) Observation airplanes cannot execute daylight
battle reconnaissance missions in areas dominated by hostile
fighter aviation without serious losses. If they must be em-
ployed for such reconnaissance regardless of the probability
of loss, they operate at maximum altitude and restrict to the
minimum the depth of penetration and time of exposure.
If attacked, they seek the protection of friendly antiaircraft
fire, losing altitude rapidly by irregular maneuver to gain
speed and eliminate attacks from below.
14
AIR RECONNAISSANCE AND OBSERVATION 25-27
(2) When the hostile air situation is such as to permit the
execution of daylight battle reconnaissance missions at low
or intermediate altitudes, the speed, course, and altitude of
the airplane are changed continuously while over enemy ter-
ritory to avoid effectively aimed antiaircraft fire. Pilots avoid
circling objectives or remaining in restricted areas for more
than 1 minute at a time. If the required information cannot
be obtained in 1 minute, the pilot withdraws some distance
and reapproaches the objective from a different direction at
a different altitude.
■ 26. Airdromes. — a. Because of the profitable targets they
present for enemy air attack, the use of group airdromes for
reconnaissance and observation aviation supporting ground
forces should be avoided whenever practicable.
b. The airdromes of units of reconnaissance and observa-
tion aviation should be located in the vicinity of the supported
unit and included in its communication net whenever it is
practicable.
(1) Units of reconnaissance aviation supporting combat
aviation should be based within the base area of the sup-
ported force and should be included in its ground and air
communication net.
(2) Units of reconnaissance and observation aviation op-
erating in support of ground forces should establish advance
landing fields in the immediate vicinity of the command post
of the unit which they support.
c. Airplanes should be concealed if cover is available on or
accessible to the airdrome. If cover is not available, the air-
planes should be dispersed.
■ 27. Camouflage. — a. Reconnaissance and observation air-
planes should be camouflaged whenever possible to reduce
their distinguishability by enemy ground and air forces.
Flight camouflage is generally ineffective early in the morning
or late in the afternoon and when the airplane is silhouetted
against a cloud background. It is of limited value against air
observation when the angle of view is horizontal or nearly so.
b. Proper camouflage of airdromes, airdrome installations,
landing fields, and airplanes on the ground will materially
reduce their distinguishability. Simulated airdromes with
salvaged and dummy airplanes present a means of misleading
15
27-28
ARMY AIR FORCE FIELD MANUAL
the enemy. The amount of camouflage required at advance
landing fields depends on the number of airplanes located
there and the attitude of the enemy. One or two airplanes on
an advance landing field normally would not be a profitable
target for enemy air attack, but if it is enemy practice to
attack such targets then the airplanes should be concealed
when present. (See FM 5-20.)
■ 28. Operating Information for Air Commanders. — In actual
operations there will rarely be an occasion when all the mis-
sions desired can be performed. Air commanders should
maintain an adequate reserve for pending developments and
always guard against exhausting their units prior to the
arrival of the final or critical phase of the battle. Accom-
plishment of this objective may be facilitated by the following
procedure:
a. Anticipate the developing situation by keeping in close
touch with the plans of the superior commander by —
(1) Frequent conferences with the staff of the supported
unit.
(2) An adequate exchange of liaison officers.
b. Detail only a reasonable number of air observation teams
to be on the alert.
c. Advise all personnel when they are not subject to call
in order that they may take advantage of a designated period
for needed rest.
d. Combine missions whenever possible.
e. Advise the commander of the supported unit when the
remaining number of air observation teams available to con-
duct missions begins to encroach upon a reasonable reserve.
16
CHAPTER 2
AIR RECONNAISSANCE FOR AIR FORCE AVIATION <
Paragraphs
Section I. General 29-30
n. Securing Information 31-47
III. Support of air attack 48-63
Section I
GENERAL
■ 29. Purpose. — Air reconnaissance is performed in support
of air force aviation for the purpose of developing objectives
and of obtaining information essential to the accomplishment
of combat missions. In some situations combat units may
themselves be required to obtain much of the information
they need; however, reconnaissance aviation normally pro-
vides air reconnaissance as a service of information for
combat aviation.
■ 30. Mission. — Offensive air operations may be conducted
over either land or sea areas, therefore units performing air
reconnaissance for combat aviation forces must be trained
and equipped to operate effectively over land or sea. It is
essential that the area covered by reconnaissance aviation in
gaining information for air force aviation extend far beyond
the sphere of action of ground forces and that it include all
probable objectives for the application of air power.
Section n
SECURING INFORMATION
■ 31. General. — The air offensive relies on air reconnais-
sance for current information of known objectives and for
the development of new objectives.
■ 32. Search op Sea Areas. — a. Reconnaissance aircraft may
be employed in search operations over sea areas in one or
more of the following ways :
(1) In cooperation with, or in lieu of, surface vessels en-
gaged in search operations.
17
32-33
ARMY AIR FORCE FIELD MANUAL
(2) In cooperation with ship or shore based naval recon-
naissance aircraft.
(3) In independent reconnaissance missions in support of
GHQ aviation forces.
b. Reconnaissance missions over sea areas will, in general,
have one or both of the following purposes:
(1) To prevent the undetected approach of a hostile naval
force. In the normal case, the desirable limit of this opera-
tion will be sufficiently in advance of the territory to be pro-
tected to prevent a surprise attack being launched by
surface or air against the protected locality.
(2) Search for specific objectives in defended areas. In
this type of search operation, the profitable limit of search
is normally the radius of action of the friendly air striking
forces.
■ 33. Search Terminology. — The following terminology is
employed in the discussion of methods of search. (See fig. 1.)
Search. — Reconnaissance for the purpose of locating objec-
tives in sea areas within which little or no information is
available concerning enemy activity.
Scout.~An airplane engaged in search.
Scouting line (AB). — A straight, broken, or curved line on
which scbuts are located in a formation suitable to conduct
a scouting operation in accordance with a definite plan.
Scouting distance (FN) . — The distance in miles between ad-
jacent aircraft on a scouting line. Under ordinary condi-
tions a distance equal to seven-tenths of the radius of
visibility is considered sufficient leeway for air navigational
errors and changes in weather conditions, since for the
parallel part of the search the scouting distance will be
1.3 times the radius of visibility (twice the radius of visibility
less allowance for error) .
Scouting front (OP) . — The distance in miles measured along
the scouting line from the extremity of visibility on one
end of the scouting line to the extremity of visibility at the
opposite end of that line.
Scouting interval (QRTSC). — The distance in miles meas-
ured between two scouts which are patrolling the same
line, measured along this line. (This definition is used
only in certain methods of search.)
18
AIR RECONNAISSANCE AND OBSERVATION
33
Position circle (UK). — A locus of position points of a force
which has proceeded a known or assumed distance from a
known or assumed point of departure. The circle is drawn
with the point of departure as a center and a radius equal
to the distance covered by the force. Point H represents
the last reported position of enemy surface craft.
Scouting course (AD) . — The course made good by scouts
when searching toward the enemy or across his probable
routes. Scouting course, line AD, is 90°.
Figure 1. — Terminology chart.
Line of departure (AB) . — The initial position of a scouting
line, from which scouts proceed on their prescribed courses
for search.
Line of retirement (DE). — The position of the scouting line
at which a search to the rear is initiated.
Line of return (FG) . — The position of the scouting line where
scouts leave their stations on the scouting line and return
to their bases.
Maintenance of scouting line (OP). — The scouting line is
said to be maintained when scouting distance and scouting
front are kept constant.
Line of bearing (AB) . — Line of bearing of a scouting line is
the direction of a straight scouting line from a reference
19
33-34
ARMY AIR FORCE FIELD MANUAL
point, expressed as a true bearing from that point. Since
A is the reference point, the line of bearing of the scout-
ing line is 180°.
Point of origin (A-B) . — The point of origin of a scouting
line is the geographical position of one end of the initial
position of the scouting line.
Radius of visibility (LM). — The radius of a circle from the
center of which the object to be observed can be seen in
any direction.
■ 34. Factors Affecting Search. — The methods to be used
in search operations can be determined only after careful
consideration of the factors which may influence the search.
Some of the more important factors are —
a. Characteristics of searching aircraft as to range and
speed. — These characteristics affect the size of the area that
can be searched, the time required for search, and the fre-
quency with which the search can be repeated.
b. Number of aircraft available for search. — This factor
primarily affects the size of the area that can be searched.
c. Availability of convenient base or bases from which
search operations may be conducted. — This becomes a major
factor if the operating base or bases are located in areas con-
siderably removed from the coastal frontier, as such location
necessitates the operation of aircraft over unprofitable land
areas prior to taking up the search.
d. Size and shape of area to be searched. — These factors
have a direct bearing on the number of airplanes required,
the hours of daylight essential for the operation, and the
method of search employed. The search of a long narrow
area extending seaward to the limit of the radius of action
of the scouts presents problems materially different from
those that arise in the search of a long coastal area of
limited depth seaward.
e. Time available for search. — Sea search at night is rela-
tively unprofitable; hence, the amount of daylight available
for the conduct of the search will influence the selection of
the search method.
/. Weather conditions. — Weather is a factor primarily be-
cause of its effect on visibility and the safety of flight.
Weather conditions, if sufficiently unfavorable, may preclude
flight operations entirely.
20
AIR RECONNAISSANCE AND OBSERVATION 34-35
g. Flight navigational errors. — The scouting distance nor-
mally is based upon the estimated radius of visibility in
the search area for the type of objective sought, less the
allowance for air navigational errors; hence these errors in-
fluence the number of scouts required for the search of a
given area.
h. Location, direction, and rate of movement of objective. —
The location, direction, and rate of movement of the objective
directly influence the extent of the area that must be covered.
The rate of movement and the time elapsed since the objective
was last sighted will determine the size of the position circle.
■ 35. Methods of Search. — a. Search operations may be
conducted in a wide variety of methods. No one plan is
adaptable to all situations. The methods selected for em-
ployment in any particular situation should be well suited to
the conditions existing at the initiation of the search and
those likely to be encountered during the operation.
b. Search plans should be as simple as possible. The
problems of navigation, particularly when operating over sea
areas out of sight of land, are tremendously increased if the
plan requires that a multiplicity of courses be flown during
the mission.
c. Aircraft engaged upon search missions usually operate
singly within assigned subareas or along designated courses,
the whole operation being so coordinated as to insure com-
plete coverage of the entire area to be searched. When the
number of aircraft available is insufficient to examine effec-
tively all of an area desired to be searched, it is far better to
search the entire area as thoroughly as possible than to search
completely a portion believed to be critical. Search operations
may be performed by aircraft in tactical formation whenever
the situation is such as to require either offensive or defensive
action beyond the capabilities of individual aircraft.
d. When the immediate attack of objectives discovered
during search operations is required, the scouts are equipped
with the required offensive armament, and the search is
conducted in a manner most favorable to the success of the
attack. The tactics and technique of air attack are covered
in PM 1-10
452263°— 42- 4
21
36
ARMY AIR FORCE FIELD MANUAL
■ 36. Parallel Search. — a. Parallel search is a form of search
in which the scouts take position on a scouting line which is
advanced by the movement of all scouts along parallel courses.
b. As a method, parallel search has the following advan-
tages:
(1) It is applicable for use by long range scouts.
(2) It provides the same coverage for the whole area
searched by distributing the scouts uniformly along the scout-
ing line during the advance. Normally, the scouts are spaced
at a distance equal to twice the radius of visibility or less,
depending on the degree of concentration desired to offset
possible errors in navigation or changes in visibility.
(3) It is applicable for use by airplanes based on airdromes
dispersed generally in rear of the initial position of the scout-
ing line.
(4) It is fairly flexible. However, the orders for the search
pattern, assumed visibility, etc., should be issued well in ad-
vance of the time search is to be initiated. Last minute
■changes in orders should be avoided. If a scout drops out
shortly before the mission is to be flown it usually is preferable
to continue with the search as originally planned rather than
attempt readjustment of the scouting line at that time.
c. (1) In parallel search, the aircraft proceed from their
operating bases to initial positions on a line of departure,
which may lie along the edge of the area to be searched, along
the shore line, or in any other convenient position. The line
of departure should be so located, if practicable, that the par-
ticipating scouts can accurately locate their respective initial
search positions. The several scouts normally leave the line of
departure simultaneously and proceed along parallel courses
to a designated line of retirement.
(2) The scouting distance is normally based upon the esti-
mated radius of visibility in the search area for the type of
objective sought, less the allowance for air navigational error.
In the absence of definite information of the width of the
disposition of the forces sought, no allowance should be made
for disposition width, the search being conducted on the basis
of discovering a single vessel.
(3) The maximum distance at which the line of retire-
ment can be located is determined by the operating radius of
the scouts. The minimum distance at which the line of re-
22
AIR RECONNAISSANCE AND OBSERVATION
36
tirement should be located Is determined by the requirements
of the mission, based upon the capabilities of the enemy forces
and time and space factors.
(4) Airplanes on reaching the line of retirement normally
retrace their outward flight paths.
(5) Parallel search patterns incorporating lateral move-
ment of the scouts at the line of retirement, to permit the
use of more than double the radius of visibility (less the
allowance for navigational error) between adjacent flight
courses, should be avoided if possible. Because of the "holes"
in such search patterns, single vessels and even small forces
may escape detection, even though they remain continuously
in the searched area. However, if the objective sought is a
large naval disposition of known width or diameter, and if the
scouts available for the search are insufficient in number to
permit covering the area otherwise, they may displace later-
ally at the line of retirement a distance not to exceed the
known least dimension of the enemy disposition, returning
on courses parallel to, but one side of, their outward courses.
All airplanes should displace in the same direction.
d. A method of parallel search from a single base to prevent
the unobserved arrival of a hostile aircraft carrier within an
M K I O
/ N L 1 P
Figure 2. — Parallel search.
area from which objectives on or near the coast could be
attacked is outlined in figure 2. The area to be searched is
determined by the extent of the coast line which is to be
23
36
ARMY AIR FORCE FIELD MANUAL
defended against surprise attack. The extent of the area
which can be searched simultaneously is limited by the num-
ber of aircraft available. The coverage of only a narrow
front is shown in figure 2; the method is the same for any
practicable width of front.
e. (1). The search plan outlined in figure 2 is based upon
the following assumptions:
(a) Weather, clear; radius of visibility, 15 miles; daylight
6:00 a. m., darkness 6:00 p. m.
(b) Range of hostile aircraft, 1,000 miles.
(c) Speed of hostile aircraft, 180 m. p. h.
(d) Speed of hostile carrier, 25 m. p. h.
(e) Range of scouts, 3,000 miles.
(/) Operating speed, 180 m. p. h.
(ff) Information of enemy force — None.
(h) Time available for search — Daylight examination of
■critical areas.
(i) Scouting distance, 20 miles (twice the radius of visibility
less 10 miles for navigational error) .
(2) A and B represent two airdromes located about 100
miles apart and well in from the coast line. The line of
departure M2V is on the coast line. The line of retirement OP
is approximately 1,095 miles from the coast line. The loca-
tion of the line of retirement is determined in this case by the
performance of the enemy equipment and by the fact that
only one search is to be made every 24 hours. The deter-
mination is as follows:
Let o=maximum distance from coast line that carrier can
■ release its aircraft, steam in, and recover them,
b— operating radius of carrier-based aircraft.
c=endurance of carrier-based aircraft.
d=speed of carrier.
The maximum distance at which the hostile aircraft can be
launched, reach the coast line, and return to the carrier is
569 miles, represented by the line IJ. If aircraft are re-
Then:
a=b+ cXd
5.55 hours X 25
2
24
AIR RECONNAISSANCE AND OBSERVATION 36-37
leased on the line IJ, the carrier must steam toward the
coast and pick up the aircraft at 1,000 less 569 or 431 miles
out, represented by the line KL. If the carrier could reach
the line KL to discharge the aircraft, it could steam outward
and pick them up on the line IJ. The problem then is to
prevent the carrier reaching the line IJ (569 miles out) un-
observed. The line of retirement must be out far enough to
prevent the carrier from arriving on the line IJ between
searches. Leaving the line of departure at daylight, the
searching aircraft can reach the line I J (569 miles out) at
9:10 a. m., and the carrier must be within 600 miles of that
line to reach it by 9:10 a. m. the next day, steaming toward
the coast at 25 miles per hour. The scouts must, therefore,
search beyond the line IJ to a distance equal to 24 hours'
steaming of the carrier, divided by the rate of approach of
the carrier and scouts, times the speed of the scouts, or:
Distance=^^°25 X 180=527 miles.
569 miles+527 miles=l,096 miles, thus fixing the position
of the line of retirement OP at that distance from the coast
line. Aircraft with an operating range of 3,000 miles can
go 1,096 miles to sea and return to the line of departure with
ample allowance for operation from airdromes located well
back from the coast. The above computations do not make
any time allowance for the effect of wind, for hostile air-
craft to launch an attack after reaching the coast line, or
for the launching and recovery of the carrier-based aircraft.
An application of appropriate factors for these effects tends
to reduce the distance to the line of retirement.
■ 37. Radial Search. — a. Radial search, as its name implies,
is a method of search wherein the scouts leave a common
point and fan out radially. Even when some other form of
search is employed, the beginning and end of the search may
take the form of a radial search, since oftentimes the scouts
are based at one airdrome.
b. As a method, radial search has the following advantages:
(1) It is best suited for use by a number of scouts of short
or medium endurance operating from a single base.
(2) All scouts leave their point of origin at the same time.
25
37
ARMY AIR FORCE FIELD MANUAL
(3) An equal coverage is obtained in all directions to which
the search is projected in, roughly, the same elapsed time.
(4) During the period when the scouts are near the point
of origin, they are relatively close together. This results in
a better coverage of that part of the area nearest the point
of origin, and also permits early concentration of scouts at
any objective found near the origin.
(5) Unless sectors are omitted, the flanks of the area
are constantly covered against enemy approach.
c. Disadvantages of radial search are as follows:
(1) It is not adapted to search of very long radius. As
the scouts fan out, a distance is reached beyond which the
scouting interval would become excessive. This can be over-
come by using a large number of scouts in a limited sector,
but would not result in economy of forces.
(2) Except near its outer limit, the scouting front is not
as great as in other standard methods.
(3) The coverage over the area is not equally efficient.
SHORE
Figure 3. — Radial search followed by parallel track search —
2V= 2 X visibility.
26
AIR RECONNAISSANCE AND OBSERVATION
37
(4) Because of the wind, all the scouts usually do not reach
the limits of the sector at the same time.
d. There are a number of forms of radial search, each of
which has its own particular advantages and disadvantages.
(1) When a return search is desired, the airplanes on
reaching the line of retirement return along parallel tracks.
This method is feasible when the maximum distance between
scouts at the line of retirement equals twice the visibility.
Figure 3 illustrates this search pattern.
(2) If the search has been flown so that the distance be-
tween scouts is three times the visibility, at the line of retire-
ment, complete search can be obtained by each scout moving
laterally the radius of visibility at the line of retirement and
then returning to his base. This is illustrated in figure 4.
(3) If a complete return search is not required, the scouts
on reaching the line of retirement move laterally one-half the
radius of visibility and then return to their base. The num-
ber of scouts required is thus less than if each scout retraced
its outward course. This form of search provides practically
complete coverage at the outer limit of the search area and
also insures double coverage of the ipner part of the area
on the return search, due to the convergence of the scouting
courses.
(4) If the area to be searched has considerable depth and
it is desirable that the search be completed as quickly as
possible, the double bank method of radial search is indi-
cated. In this method of search, the search area is divided
into inner and outer sectors. One group of scouts searches the
inner sector, while a second group concurrently searches the
outer sector. This method of search is particularly valuable
when the search must be completed as shortly after daylight
as possible. In such a case, the outer bank of scouts takes
off at such time as will- permit them to arrive on the line of
retirement of the inner bank at daylight; the inner bank
takes off at such time as will permit them to initiate their
search at daylight also. The search of the two sectors thus
proceeds concurrently and, if the sectors are approximately
equal in depth, the search is completed in half the time that
would be required if one group of scouts covered the entire
area. This method of search lends itself to the combined
27
28
AIR RECONNAISSANCE AND OBSERVATION
37-38
use of long and short range scouts,
double bank radial search.
Figure 5 illustrates a
c-8
S-IO
- INNER BANK-
■ OUTER BANK ■
SHORT RANGE SCOUTS ARC-* IONS RANGE SCOUTS
Figube 5.; — Radial search, double bank method.
■ 38. Radial-Parallel Search. — a. A combination of radial
and parallel search methods may be employed in searching for
an objective reported to have been in a specific position at a
previous time, with location, time, and space factors such as
to preclude the possibility of the objective being in the im-
mediate vicinity of the base at the time the search is started.
b. In this method of search the scouts fan out radially on
leaving the base. On reaching a predetermined line (which
may be either straight or curved and which may be reached
individually or concurrently) , the scouts change from diverg-
ing to parallel courses. On reaching the line of retirement
the scouts may either return along their outward flight
courses or directly to the base. If the critical area is far
offshore, the scouts should be kept in formation while pro-
ceeding to the point from which the critical part of the search
will begin. This should insure a more thorough search of
452263°— 42— 5
29
38
ARMY AIR FORCE FIELD MANUAL
the critical area since the line of departure is more accurately
established thereby.
c. In the planning of this form of search, the essential re-
quirement is that the spread of the search fan and the depth
of the search be sufficient to include all possible positions of
the objective under the existing conditions of elapsed time,
relative speed, wind force and direction, and other influencing
factors. The required fan spread and depth of search can be
accurately determined graphically by plotting a large number
(twenty or more) possible objective courses (evenly spaced
through the area of possible movement) , and plotting for each
such course the point at which the objective can be intercepted
under the conditions of time of take-off that can be made good
by the scouting force, the estimated wind in the search area,
and the assumed maximum speed of the objective. If the
points of interception are connected by smooth, curved lines,
they will outline the area that must be searched and thus
show the required search fan spread and the depth of search
necessary.
d. In the event that time does not permit such accurate
determination of the objective's position area and hence of the
required fan spread and search depth, that area can be de-
termined approximately in such a manner as to insure that the
c
Figure 6. — Radial-parallel search.
30
AIR RECONNAISSANCE AND OBSERVATION
38
objective cannot be outside the search pattern. To be on the
safe side, such approximations will always include more area
than the objective can possibly reach and hence will require
more airplanes than would be necessary with the more exact
determination, but nevertheless these methods are of' value
when time is a vital element.
e. A radial-parallel search plan based on one method of
approximating the area to be searched is shown in figure 6.
/. (1) This search plan is based on the following assump-
tions and command decisions —
(a) The objective was located under such conditions that
it could not be trailed. Its subsequent movements are not
known. It is estimated that the location report is accurate
to within 20 miles.
(b) Receipt of the location report was delayed 2 hours due
to communication conditions.
(c) Time and space factors necessitate minimum time for
plotting search pattern.
id) Scouts will take off individually at such time as to ar-
rive on the line KL where scouts change from diverging to
parallel courses simultaneously. The scouting line will
advance from the line KL as a straight line.
(2) The search pattern is plotted as follows —
(a) The base B and the reported position of the objective
O are plotted, using a convenient scale.
(b) The point C at which interception would be made
under the prevailing wind conditions, assuming the objective
moved continuously directly away from the base on a course
in prolongation of the line BO at maximum speed, and that
the probable error in the reported position would not exceed
20 miles, is plotted.
Note. — In computing interception, use the time of take-off that
can be made good and the air speed at which it Is planned to
operate.
(c) With a distance equal to OC as a radius and with
point O as a center, a circle is struck off.
(cf) The line EF is drawn through point O perpendicular
to the line BC. Points K and L mark the intersection of
that line with the circle. Line EF is the line at which the
airplanes will change from diverging to parallel courses.
31
38-40
ARMY AIR FORCE FIELD MANUAL
(e) Lines BK and BL, forming the triangle BKL, are
drawn. Under the assumed conditions, if the objective lies
on the line EF, or anywhere on the base side of that line, it
must lie within the triangle BKL. Hence the area BKL
represents the area to be covered by radial search.
(/) Points G, H, I, J, M, etc., mark the positions of the
individual airplanes on the line KL. They are spaced 1.3
times the radius of visibility under the existing visibility con-
ditions, point G being seven-tenths the radius of visibility
inside point K. When the scouts arrive on the line KL they
change their course so as to fly parallel to the line JSC.
(fir) Since the distance OC represents the maximum dis-
tance the objective can travel prior to interception, the ob-
jective must lie within the semicircle KCLO, if it is not in
the triangle BKL. Hence the arc KCL is the line of retire-
ment. On reaching the line of retirement, all scouts discon-
tinue the search unless otherwise instructed, and return
individually to the base by the most direct route.
(ft) Lines S-l, S-2, S-3,, etc., represent the outward courses
of the .scouts. The return courses are not shown.
■ 39. Square Search. — a. This method of search is of great
use in locating a target, whether stationary or moving.
b. It has its most frequent application in a striking force
when, on flights to a target, arrival at the dead reckoning
position fails to disclose the target. At that time the search
is begun.
c. In order successfully to prosecute the search, an assumed
visibility must be used and courses and distances to be flown
on the different legs must have been calculated before take-off
or at least prior to arrival in the target area. Figure 7
shows the pattern of the search.
d. The length of the search is dependent upon the amount
of fuel available for search, opposition encountered over the
target, the assumed visibility, and the errors in the dead
reckoning position of the target as obtained by the navigator.
■ 40. Cross-Over Patrol. — a. This type of patrol is highly
satisfactory when patrolling a channel but can be used under
other circumstances.
32
AIR RECONNAISSANCE AND OBSERVATION 40-41
6V
2V
6V
2V
o
DR position
of target
Then: XY=
--2V
4V
Figure 7. — Square search — V= visibility.
b. A cross-over patrol for covering a channel between two
land areas is shown in figure 8.
Let: A=aircraft speed.
£=enemy speed.
V= radius of visibility.
JTF=length of patrol.
D=effective length of patrol.
2VA.
E
However, the effective length of area patrolled (D) equals
since visibility takes care of outer limits. Aircraft pass
over point Z at intervals equal to ^ and over points X and Y
hi
at intervals equal to
E
■ 41. Endless Chain Patrol. — a. This type of patrol may be
used when it is necessary to establish a patrol between two
points in such a manner that no moving craft can pass with-
out being detected.
b. Although the cross-over patrol accomplishes this more
economically, it may be necessary, due to the distance between
the two points, to use the endless chain method.
33
41
ARMY AIR FORCE FIELD MANUAL
AIR RECONNAISSANCE AND OBSERVATION
41
c. An endless chain patrol is shown in figure 9.
Let V=radius of visibility.
J?=enemy speed.
IV ->
Figure 9. — Endless chain patrol.
Aircraft must pass any given point at a definite time interval
so that moving craft will not be able to enter or leave the
visibility distance without being detected.
The time interval will be:
2V
E
d. The efficiency of this patrol is unaffected by the distance
between the outward and inward tracks. In practice this
has been found to be about IV or 10 miles apart.
AREA
COVERED BT
convot
10-15 miles .
15-20 miles
DIRECTION OP
MOVEMENT
OF CONWr
>■
<
Figure 10. — Convoy patrol.
35
42-44
ARMY AIR FORCE FIELD MANUAL
■ 42. Convoy Patrol. — The name of this patrol describes
its function. To avoid enemy countermeasures, the pattern
to be used should vary. An effective one is the rectangular
type illustrated in figure 10.
■ 43. Creeping Line Ahead Search. — This type of search
may be used in conditions of poor visibility to locate a con-
voy or single ship which is to be escorted. Aircraft is flown
to a point several miles ahead or astern of convoy's reported
position depending upon the cirmumstances. Aircraft com-
mences the creeping line ahead search up or down the convoy's
course as shown in figure 11.
Note. — The distance of 15 miles again depends on circumstances,
for example, accuracy of own DR and probable accuracy of convoy's
reported position.
convoy's _
■
4
t
Z
I
Course '
•>
f
>
•
Figure 11. — Creeping line ahead search.
■ 44. Reconnaissance Missions. — a. Reconnaissance mis-
sions in support of aviation forces usually precede the opera-
tions of striking units in order to secure any information
required in planning for the most effective employment of
the striking unit. The requirements of reconnaissance mis-
sions frequently may be met by visual observation alone;
however, photographic equipment will always be carried on all
reconnaissance missions. Photographs frequently can be
used to advantage in supplementing information obtained by
visual means. When photographs are taken they should be
taken in pairs with 60 percent overlap to facilitate stereo-
scopic study of the included area. Air reconnaissance mis-
sions executed for aviation forces are affected by the factors
which govern the conduct of air reconnaissance as a whole,
and the most suitable method for employment in any situation
depends upon the nature of the information sought, the area
to be covered, and the existing weather conditions.
36
AIR RECONNAISSANCE AND OBSERVATION 44-47
b. Enemy opposition is to be expected during the conduct
of reconnaissance missions, particularly those involving deep
penetration of hostile territory or the examination of im-
portant enemy installations which are vulnerable to air at-
tack. Single airplanes operating at high altitude and util-
izing the existing clouds as the means of concealment will
frequently escape detection by the enemy. Reconnaissance
missions should be so planned that the exposure to active
antiaircraft defense agencies will be as brief as possible con-
sistent with the accomplishment of the mission.
■ 45. Surveillance. — Surveillance is executed for the purpose
of keeping an activity, area, or objective under continuous
observation. It is employed in support of aviation forces only
when the desired results cannot be obtained in any other way
and usually is carried out by airplanes operating singly.
When a fleeting objective has been located for the purpose of
launching an air attack against it, surveillance may be neces-
sary in order to facilitate interception by the attacking force.
Contact, development, and tracking of an enemy force may
form a progressive phase in search operations and, in such
situations, relatively protracted surveillance may be necessary.
The' security of aircraft engaged in the performance of sur-
veillance is of paramount importance. Surveillance may be
impossible in the presence of hostile fighter airplanes which
are not otherwise engaged.
■ 46. Contact.— Reconnaissance may consist of periodically
contacting air activity, area, or objective when continuous
observation, though desirable, is impracticable. Personnel
engaged in contact missions should avoid regularity, both in
the interval between successive examinations and in the direc-
tion of approach and retirement, to guard against detection
and surprise after several visits to the vicinity of the objec-
tive, particularly if the objective lies within the zone of action
of hostile fighter aviation.
■ 47. Tracking. — o. It may be necessary to track highly
mobile hostile air, ground, or sea forces to determine the
location of newly occupied enemy airdromes or air bases
or the course and disposition of enemy surface or air forces
or to secure other similar types of information. Tracking
missions may be executed either by reconnaissance forces
37
47-50
ARMY AIR FORCE FIELD MANUAL
or by aircraft detached from a tactical command in flight
for that purpose, as when hostile aircraft are encountered
during the conduct of a combat mission.
b. (1) Airplanes may be alerted on the ground for the
specific purpose of tracking hostile airplanes reported to be
in the vicinity. This action is of particular importance when
the location of enemy air bases has not been determined.
Carrier-based aircraft raiding a shore objective may be
tracked to the carrier by reconnaissance airplanes which
maintain contact with the carrier to facilitate an attack by
bombardment aviation.
(2) Tracking aircraft at night is difficult at best and may
be impossible under many conditions. However, if the area
from which enemy air forces are operating is unknown and
it is desired to locate that area, night tracking of hostile
aircraft should be attempted.
c. The presence of tracking aircraft should be concealed
from the force being tracked. In the case of aircraft the
tracking airplane should follow behind at the maximum limit
of visibility and at a somewhat lower altitude, maintaining,
when advantageous, an up-sun position. In tracking naval
surface forces defended by aircraft, the tracking mission
should be flown in the manner prescribed for contact
missions.
Section in
SUPPORT OP AIR ATTACK
■ 48. General. — Reconnaissance aviation supports the strik-
ing aviation in air attack by —
a. Developing objectives.
6. Guiding air striking forces to the objective.
c. Providing weather data over the route to and at the
objective.
d. Illuminating targets for night attack.
e. Determining the results of attack.
■ 49. Developing Objectives. — For methods of developing
objectives for air attack see section II.
■ 50. Guidance. — a. When attacking units must operate over
terrain with which they are not familiar they may have
difficulty in locating objectives under conditions of low visi-
38
AIR RECONNAISSANCE AND OBSERVATION 50-51
bility, especially when adequate flight maps are not available,
or at night. Reconnaissance units may be of great assist-
ance by providing information of the best route to and from
the objective and also data as to landmarks en route that
may be of value as check points. A single airplane free to
search can locate a particular terrain feature more readily
than can an attacking formation which may be operating on
a carefully timed and coordinated schedule. Reconnaissance
personnel familiar with the route may be utilized as navi-
gators in the attacking units when desirable.
b. Reconnaissance aviation may be of great assistance to
attacking units during night operations by dropping flares
to serve as beacons to guide the attacking units to their ob-
jectives. The distance at which flares can be seen at night
varies with weather conditions, and under favorable circum-
stances may be as great as 75 miles. The guiding aircraft
precede the attacking unit by a suitable interval, depending
upon conditions of visibility, and drop flares at predeter-
mined intervals along the route without reference to particu-
lar terrain features to provide directional guidance, or at
previously determined positions along the route to provide
positional guidance. The plan of operation should provide
for dropping flares at such intervals or in such localities as
will facilitate the attack without indicating to the enemy
the objective. Guiding aircraft must avoid flying in the
vicinity of the objective until the attacking unit is ready to
launch the attack. Guiding flares are dropped from high al-
titudes if it is contemplated that they will be visible for
great distances; at other times they may be dropped in the
same manner as are flares intended for illumination of the
ground area qver which they are dropped.
■ 51. Weather Data. — a. Weather is a factor in determining
the manner in which an air attack is delivered. When the
objective is located deep in enemy territory it may be nec-
essary to obtain special weather information for the objec-
tive area. This is a task for reconnaissance aviation
supporting aviation forces.
b. The technique of executing a weather reconnaissance
mission is similar to that for other types of distant recon-
naissance. The orders for the mission will prescribe the
information desired.
39
52
ARMY AZR FORCE FIELD MANUAL
B 52. Illumination of Targets. — a. (1) The reconnaissance
airplanes responsible for illuminating the targets may ac-
company the striking force to its initial point or may proceed
there independently, arriving at a designated time.
(2) The number of illuminating airplanes required will
depend upon the nature of the target and the ease or diffi-
culty with which it may be located at night. Fewer air-
planes are required to locate and illuminate a target disposed
in length, such as a road or railroad, than are required for
the location and illumination of a target which is more or
less a point, such as a bridge, building, or airdrome. The
amount of natural illumination and the proximity of the
objective to easily recognizable landmarks will also be fac-
tors. Because of control difficulties, more than nine air-
planes should not be assigned to a single illumination task.
(3) The navigators of the leading element of the illumi-
nating force should be provided with aerial photographs of
the target and its immediate vicinity to enable them to
orient themselves by the light of the first flares dropped.
Such orientation will reduce the possibility of an illumina-
tion failure on the first trip over the target.
&. The initial task of the illuminating force is the location
Of the target, The airplanes charged with this portion of the
task fan out on leaving the initial point, taking positions
abreast on a line at approximately 1-mile intervals. When
about 5 miles from the estimated target center, these airplanes
begin dropping illumination flares at 15-second intervals.
Flares are dropped until the airplanes have passed 5 miles
beyond the estimated target center, unless "target located"
is signaled sooner. On receiving the target located signal, the
initial illuminating airplanes withdraw. If the target has not
been located, the search is repeated in accordance with the
mission plan.
c. The next part of the illuminating task is to illuminate
the target sufficiently to permit the bombardiers of the at-
tacking force to lay their bomb sights on it, or to provide an
illuminated aiming point. The airplanes charged with this
part of the task fly to the rear and above the first group of
illuminating airplanes. The observer first sighting the target
signals by radio or pyrotechnics "target located"; he will then
mark the target by flying low over it and releasing illuminating
40
AIR RECONNAISSANCE AND OBSERVATION 52-53
flares, or by dropping a row of white phosphorus bombs
through the target center. The remaining airplanes of the
second part of the illuminating force then drop additional
flares on the line of bombing approach, beyond the target
(keeping the target within the flare area of illumination) , or
place intersecting rows of white phosphorus bombs through
the target at such an angle that the attacking force is given
a definite aiming point. They then withdraw.
d. On withdrawing, the illuminating force returns to its
base. The difficulties of rallying at night, as well as the in-
effectiveness of supporting night gun fire, render it inadvisable
for the illuminating force to attempt to rejoin the bombard-
ment formation for the return flight.
■ 53. Determination of Results of Attack. — Determination
of the results of air attack is a function of bombardment avia-
tion. When, however, it is impracticable for bombardment
aviation to accomplish this, reconnaissance aviation may be
employed for the purpose. The reconnaissance airplane may
accompany the attacking force or may examine the target
later. Aerial photographs provide the most satisfactory rec-
ord of the results of air attack.
41
CHAPTER 3
AIR RECONNAISSANCE AND OBSERVATION FOR
GROUND FORCES
Paragraphs
Section I. General 54-56
n. Distant and close reconnaissance missions 56-58
III. Battle reconnaissance missions 59-67
IV. Liaison missions 68-70
V. Adjustment of fire for mobile artillery 71-76
VI. Cooperation with Cavalry 77-81
VII. Cooperation with seacoast artillery 82-89
VIII. Cooperation with armored and motorized forces. 90-94
Section I
GENERAL
■ 54. General. — Observation aviation operating in support of
ground forces does not replace any of the other intelligence
agencies available f o the commander of those forces but sup-
plements them and can provide the commander with infor-
mation which he cannot secure by any other means.
■ 55. Tasks. — a. Observation aviation is employed in the re-
connaissance of areas in and beyond the zone of reconnais-
sance of ground troops. Its purpose is to obtain for the
supported commander original and/or supplementary infor-
mation on which he will base his tactical decisions. The re-
connaissance of movements of hostile troops in rear and on
the flanks of battle and of hostile detrucking points and
detraining stations is of especial importance.
b. Observation aircraft are also employed for the execution
of artillery and liaison missions. Whenever practicable, air-
planes are reserved for missions involving the observation of
objectives which are beyond the effective view of ground
troops.
c. Normally, one or two airplanes are maintained on the
alert at the squadron airdrome or at an advanced landing field
near the division, corps, or army command post, prepared to
execute liaison or emergency missions on order of the division,
corps, or army commander.
Section n
DISTANT AND CLOSE RECONNAISSANCE MISSIONS
■ 56. Enemy Counterreconnaissance. — The enemy will at-
tempt to limit our air reconnaissance and observation by all
42
AIR RECONNAISSANCE AND OBSERVATION 56-58
means at his disposal. If he elects to effect "Uitable concen-
trations of fighter aviation in a ground battle area, he may
compel the use of combat type airplanes for or in support of
observation missions involving flight over his territory.
■ 57. Army Reconnaissance. — Reconnaissance missions for
the purpose of securing information essential to the army
commander are performed by the observation aviation at-
tached to or supporting the army.
a. When the army starts its movement toward the enemy,
the army aviation performs air reconnaissance missions in
the area in which the army commander is vitally and immedi-
ately interested. These missions are executed well within
enemy territory and cover the rear areas, flanks, and front of
the hostile forces. The scope of army air reconnaissance
includes such items of information as the location, strength,
composition, route, and directions of movements of hostile
forces; hostile defensive organization, lines of communica-
tion, and traffic thereon; construction; the location of enemy
supply establishments, bivouacs, and airdromes; route recon-
naissance; and the outstanding features of the terrain.
b. When the army operates on an independent mission
in a separate theater, the army aviation performs both the
normal GHQ and army reconnaissance functions. When on
such a mission, the army may have combat aviation units
attached. The army reconnaissance aviation performs the
reconnaissance functions necessary to the practical employ-
ment of such support forces in the event the latter are not
prepared to perform their own reconnaissance.
■ 58. Corps and Division Reconnaissance. — a. Corps air re-
connaissance missions properly commence when the corps
zone of operation is initially designated, and continue through-
out the period during which the corps is in contact with the
enemy. They are executed to secure detailed information of
tactical importance to the corps commander within the area
for which he is responsible. Corps reconnaissance is of a
much more intensive and detailed nature than is the more
distant army reconnaissance upon which the general plan for
the employment of the corps is based. Corps reconnaissance
missions usually involve continuous day and night observation
within the corps zone of operation, for obtaining detailed in-
43
58-59
ARMY AIR FORCE FIELD MANUAL
formation relative to the location of hostile advance forces,
their strength, composition, movements, defensive organiza-
tion, supply arrangements, and detraining points.
b. When contact between the two main hostile forces is
imminent and the division air area has been defined, the
division aviation takes over the intensive aerial reconnais-
sance of that area. Throughout the period that the division
is on the front, continuous up-to-date information of the
enemy and of the terrain, especially in the hostile divisional
areas, is necessary to the division commander for the plan-
ning and execution of his operations. Particular attention
is given to indications of enemy withdrawal, traffic, move-
ments of reserves and reinforcements, defensive works,
bivouacs of troops and of trains, artillery positions, ammuni-
tion distributing points, and command posts. Night air re-
connaissance will be especially valuable in detecting rail
traffic and troop and vehicle movements on highways; early
morning and late evening flights often will pick up the end-
ing or the beginning of such movements. Observation of the
flashes of the guns during darkness affords an excellent op-
portunity for locating active artillery position. Ground ob-
servation, within the limits of visibility, can furnish much
information of activity in the forward areas. The burden of
air reconnaissance normally must be borne by the heavier-
than-air units working with the division. . Reconnaissance in
the division air area requires close attention to minor details
and usually involves the frequent photographing of enemy
works, including trench systems, wire entanglements, ma-
chine-gun emplacements, artillery positions, supply dumps,
command posts, and communication systems.
Section HI
BATTLE RECONNAISSANCE MISSIONS
■ 59. General. — o. Battle reconnaissance missions include
the location of the opposing front lines, observation of the
progress of combat, location of hostile resistance holding up
an advance or of enemy penetrations into our positions, and
assembly of hostile troops for attack or counterattack.
b. During an attack the division commander and com-
manders of subordinate and adjacent units are particularly
44
AIR RECONNAISSANCE AND OBSERVATION 59-61
concerned with points along the front where the attack has
progressed; points where the attack has been stopped; points
where units have been separated, leaving a gap in the line;
and points where hostile forces are forming for counterattack.
c. When the enemy is launching an attack, these com-
manders are particularly concerned with points where pene-
trations have been effected and with the location and
movement of hostile reserves.
d. The task of maintaining contact with our own front
line units and locating and reporting enemy installations and
activities near the front is primarily a responsibility of the
ground troops. When these agencies prove inadequate, air-
planes may be used to assist in the accomplishment of these
tasks. Before directing missions of this type, commanders
should take into consideration the high: casualty rate to be
expected and should balance this factor against the value of
the information desired.
■ 60. Aerial Photographs.— Much of the information of
friendly and enemy locations and activities in the forward
areas can frequently be obtained by proper and systematic
use of high altitude vertical and oblique aerial photographs.
A large scale reconnaissance strip can be made of the general
front line areas of a division front in a very short time. Over-
lapping verticals are the most suitable type of photographs
for such study. The information obtained from photographs
is frequently more complete and accurate than can be ob-
tained by visual means in this area. Photographic recon-
naissance is also much less hazardous to flight personnel and
materiel than a low altitude visual observation mission. For
these reasons, aerial photography supplemented by terres-
trial observation should be fully exploited, visual observation
from an airplane being employed only when all other means
prove inadequate or too slow.
■ 61. Location of Friendly Front Lines. — a. The location
of the friendly front line may be obtained by signaling assault
battalions "Display marking panels." Front line companies
then display marking panels without delay. The observers
may signal each assault battalion in turn "Display identifi-
cation panels" and "Report your front line by pick-up mes-
sage." If the battalion commander is in doubt as to the
45
61
ARMY AIR FORCE FIELD MANUAL
location of his assault companies, he notifies the observer
of this fact by signal or pick-up message.
b. These methods of locating the friendly front line require
a complete understanding between the ground troops and the
air observer. Proper teamwork can be obtained only after
thorough training. Each rifle squad carries six marking
panels — three black marking panels for use on snow or other
light-colored background, and three white marking panels
for use on normal background. When panels are to be used,
the pilot flies toward the front until friendly troops are no
longer exposed; the observer then identifies himself by means
of a prearranged signal. He then fires a prearranged pyro-
technic signal calling on the infantry to "Mark front lines"
by displaying marking panels. The observer marks the line
of panels on his map or sketch for dropping.
(1) The use of panels to mark the front line requires that
the infantrymen recognize friendly airplanes. The in-
fantry should be warned, if practicable, of the approach of
a friendly airplane which should have distinctive markings
on the wings or fuselage and may also carry streamers for
purposes of identification. It is essential that prearranged
signals be employed as a means of identification to minimize
the possibility of the display of marking panels to a hostile
airplane and the danger of friendly airplanes being shot down
by friendly troops.
(2) Panels facilitate the accurate location of the front line,
but their use cannot be depended upon in all situations for
the following reasons :
(o) Infantry engaged in an attack may be too much oc-
cupied to display panels.
(b) It is dangerous to display panels when they may be
seen by enemy air observers.
(c) In rolling or wooded areas, panels displayed in sheltered
localities may not be seen from an airplane.
(.d) The infantryman may lose his panel or throw it away
to lighten his load.
(c) Panels that have become dirty may not be seen by the
observer, even when properly exposed.
c. If the Infantry fails to display panels or if they are not
seen, the observer then seeks to effect location by flying at
46
AIR RECONNAISSANCE AND OBSERVATION 61-63
a low altitude to a point well defined by landmarks, located
near where friendly troops were last seen or reported.
If the front line has advanced appreciably, the troops seen
in this vicinity may be exposed and small units of transport
may be seen. The observer then continues toward the front
until troops are observed taking cover from hostile fire in
shell holes, fox holes, behind trees, walls, or crests of slopes;
or moving forward by infiltration. When any of these con-
ditions exist, the pilot turns and flies generally along the
front, the observer marking its location on his map. While
over the front the pilot must fly an irregular course, using
all of his maneuverability and speed to minimize the danger
of being shot down by ground fire. This method of front
line location is used only when all other visual methods fail
and the time element completely precludes the use of aerial
photography.
d. The location of the friendly front line is reported by
dropped message to the division command post and when
desirable also to subordinate command posts.
■ 62. Information To Be Furnished Observer by Infantry
Commander. — When applicable, the following information
should be furnished the observer (and pilot) by the infantry
commander prior to the execution of any battle recon-
naissance —
a. Definite and limited mission.
b. Specific information desired.
c. Pertinent information of our own and hostile forces
necessary to the intelligent accomplishment of his mission,
including scheme of maneuver.
d. Method, time, and place of reporting information ob-
tained.
e. Information concerning location of command posts, cur-
rent signal operation instructions, especially pyrotechnic sig-
nals and identification panel code.
■ 63. Information Required by Infantry Commander. — a.
The air observer on a battle reconnaissance to observe enemy
activities especially seeks information of —
(1) Location, strength, composition, and direction and rate
of movement of possible reserves and tanks.
47
63-65
ARMY AIR FORCE FIELD MANUAL
(2) Location of hostile strong points or centers of resistance.
(3) Location or movement of hostile artillery.
(4) The organization or strengthening of hostile positions.
(5) Obstructions that interfere with the advance of
friendly infantry.
b. The air observers on a battle reconnaissance to observe
friendly activities seek information of —
(1) Location of front line.
(2) Points along the front where our attack has pene-
trated and progressed.
(3) Points along the front where our attack has stopped.
(4) Gaps in our lines.
(5) Movements of our troops.
c. Information obtained is transmitted to the appropriate
infantry command posts and to the artillery.
d. Penetrations of enemy territory to secure information
are made as brief as possible. Circling to permit continuous
observation and regularity in method and direction of ap-
proach and retirement will be avoided. (See pars. 204 and
25b.)
■ 64. Information of Artillery Fire. — The observer notes all
areas in which artillery shells are seen to be falling. This in-
formation is of great value to division headquarters and to the
observer himself in carrying out his mission. Hostile shells
falling on a portion of the line previously occupied by enemy
troops indicate a retirement which probably will be followed
by advance of friendly troops. Hostile shells falling wide of
friendly operations indicate that the enemy lacks knowledge
or observation of such operations. In observing enemy shell
bursts, the locality, frequency, quantity, and damage done
should be noted and reported as accurately as possible, because
this information will assist division headquarters in esti-
mating the enemy's most likely line of action and hostile
artillery strength and caliber, and in deciding the counter-
battery measures necessary.
■ 65. Pyrotechnic Signals. — Prearranged pyrotechnic sig-
nals may be used by front line units to communicate with the
airplane or with friendly artillery. Particular attention is
paid to reporting and relaying these signals. Important pyro-
technic signals are immediately transmitted by radio to di-
48
AIR RECONNAISSANCE AND OBSERVATION 65-69
vision headquarters; when there is any doubt as to the mes-
sage getting through, it is confirmed by a dropped message.
Infantry signals to the artillery are transmitted by the air-
plane to the artillery command post concerned.
■ 66. Panel and Pick-up Messages. — Messages may be trans-
mitted to the airplane by means of panels displayed at panel
stations of battalion, regimental, brigade, and division head-
quarters. Such signals are employed in accordance with an
air-ground liaison code of signals. Written messages may
be delivered direct to the airplane by means of the pick-up
method, from a station near the command post of the head-
quarters at which the message originates. The technique of
picking up messages is described in FM 24-5.
■ 67. Preparation of Messages.— Messages should be accu-
rate, legible, and in appropriate detail. Messages should be
dropped as soon as possible after important information has
been secured, thereby affording the ground commander the
maximum opportunity to use the information and preventing
its loss in case the airplane is shot down. Messages are
prepared in duplicate; the original is dropped, and the dupli-
cate is attached to the observer's written report which is
turned over to the unit operations officer immediately upon
completion of the mission.
Section IV
LIAISON MISSIONS
■ 68. Purpose. — liaison missions are performed to assist a
commander in locating and maintaining contact with ele-
ments of his own, adjacent, or higher units, or to transmit
information or orders when such transmission can be more
effectively accomplished by air messengers than by other
means of communication.
■ 69. Procedure. — When a liaison mission is executed for the
purpose of having a staff officer observe the terrain in an area
wherein hostile pursuit is active, the staff officer should be
a qualified aerial gunner in order that he may man the gun
of the station he occupies, which may be the only gun that
can be brought to bear within its field of fire. The loss of
effective fire from one gun station on a reconnaissance type
49
69-72
ARMY AIR FORCE FIELD MANUAL
airplane seriously reduces its def ensibility, thus increasing the
possibility of the loss of the airplane and all personnel aboard
in the event of an attack by hostile aircraft.
■ 70. Performance. — The factors affecting air reconnaissance
and observation as a whole exercise an equal influence on
command and liaison missions.
Section V
ADJUSTMENT OF FIRE FOR MOBILE ARTILLERY
■ 71. Artillery Missions. — a. Cooperation with artillery calls
for the furnishing of information to the artillery as to the
nature and location of its targets, and for assisting the artil-
lery by aerial adjustment of its fire. To accomplish its mis-
sion with effectiveness and speed under conditions of modern
warfare, the field artillery, especially long range artillery,
must be furnished with air observation. Air observation
permits reports on fire in areas defiladed from ground ob-
servers and, under favorable observing conditions, permits
rapid and accurate conduct of Are because the amount of
error, as well as its direction, can be sensed.
b. In general, artillery missions for air observers include —
(1) Registration, the adjustment of Are on a point or lo-
cality to facilitate obtaining data for subsequent fires. Regis-
tration is very rapid when the observer can locate on a
map or photo the corresponding location on the ground of
the center of impact of a group of shots.
(2) Surveillance of fires by reporting the amount of error
of initial fires for which accurate data have been prepared
by the artillery. With maps and photos, surveillance of fires
should be the rule when map or photo locations of both
pieces and target are accurately known to both observer and
the artillery.
(3) Adjustment of fire on targets previously assigned by
the artillery or located by the observer when map or photo
locations of both pieces and target are accurately known to
both observer and the artillery.
■ 72. Assignment of Missions. — a. Artillery missions are ex-
ecuted by observation aviation units with divisions, corps,
and armies. Upon request of the artillery commander, the
50
AIR RECONNAISSANCE AND OBSERVATION 72-74
division, corps, or army commander designates the type and
amount of observation aviation to be used to conduct artillery
missions.
b. The number of observation aircraft assigned to the
artillery may vary from one per division or artillery group-
ment to one per artillery battalion. If a single plane is avail-
able to a division or groupment, it is usually assigned to divi-
sion artillery headquarters or groupment headquarters for
control; then, with all battalions listening in on the estab-
lished radio frequency, any one of them can take up any
mission assigned to it.
c. In general, missions assigned to an air observer should be
those which cannot be executed conveniently or accurately
from the ground. When targets are reported by the observer,
the decision to deliver fire rests with the artillery commander.
Because of possible hostile activity and the probable need for
the aircraft on other missions, aircraft must be used on ar-
tillery missions at maximum possible efficiency.
■ 73. Air Observer. — a. Successful cooperation between ar-
tillery and supporting aviation requires very close liaison and
thorough understanding between the units concerned.
b. The air observer should be detailed from the field artillery
organization receiving air support. He acts under the orders
of the field artillery commander and is responsible for the
proper procedure and technique, except for the actual opera-
tion of the airplane. He must be qualified to operate the
signal communications to the field artillery unit.
c. The maneuvering of the airplane is the responsibility of
the pilot, who, however, will be guided as far as conditions
permit by the expressed desires of the observer.
d. The use of single-seater observation airplanes for ar-
tillery missions is limited. Pilots are not ordinarily trained
in the principles of adjustment of artillery fire. Moreover,
the pilot's concern with the handling of the airplane will
interfere with an alternate role as observer.
e. The artillery must be on the alert to assist in detecting
the approach of enemy planes and to warn the observing
airplane of such activities.
■ 74. Types of Communication. — The most effective means
of communication between airplane and ground is two-way
51
74-77
ARMY AIR FORCE FIELD ' MANUAL
radiotelegraph or radiotelephone. Radiotelegraph produces
the stronger signals, has the greater range, and is less subject
to interference; radiotelephone is the faster. Communication
by air-ground radio and ground-air panels is also effective.
With careful prearrangement, communication by two-way
radio or by radio and panels may be reduced and sometimes
eliminated. Dropped or picked-up messages are often prac-
ticable, especially if they are marked photos or maps. Visual
signals, in general, are slow and impracticable; with prear-
rangement they may have limited use.
■ 75. Location of Targets. — Under stabilized conditions, pho-
tography is the most satisfactory means of locating artillery
targets which have been camouflaged to prevent their dis-
covery. In open warfare many targets are of such a fleeting
nature that prompt action on the part of the air-observer and
the artillery with which he is working is necessary if artillery
fire is to be put down on these targets before they disappear
or move out of range. Enemy combat groups holding up
the advance and enemy reserves moving up to reinforce the
front must be taken under fire as soon as they can be lo-
cated. Hostile artillery positions must be discovered and
counterbattery fires laid down without delay.
■ 76. Procedure and Technique. — For details of designation
of targets, communication procedure, methods of registration,
adjustment, and surveillance of fires see TM 6-210.
Section VI
COOPERATION WITH CAVALRY
■ 77. General. — a. Reconnaissance and observation aviation
does not replace or supplant Cavalry as a reconnaissance
agency but is of particular value to and increases the effec-
tiveness of that arm by extending its radius of action and
directing attention to known or suspected hostile forces,
thereby obviating useless marching and conserving men,
horses, and materiel. Air observers working in cooperation
with Cavalry can furnish timely information to the com-
mander pertaining to —
(1) Disposition, strength, and composition of the hostile
main force.
52
AIR RECONNAISSANCE AND OBSERVATION
77-79
(2) Location and strength of hostile security and recon-
naissance detachments.
(3) Rates and direction of movement and routes followed
by hostile forces in the observed area.
(4) Condition of routes and bridges suitable for use by the
supported friendly units.
(5) Terrain features which may be utilized to advantage
by either hostile or friendly forces.
(6) Liaison between friendly units or parts of the cavalry
command.
b. Reconnaissance aviation is of particular value to a
cavalry commander during the initial phases of a strategic
or tactical movement. Information as to the location of
the hostile main forces, their security and reconnaissance
detachments, and their routes and rates of movement will
enable the cavalry commander to conserve his forces and to
advance more rapidly and accurately on his objective.
c. During combat, observation aviation cooperates with
Cavalry in essentially the same manner as with Infantry.
■ 78. Cavalry Requirements For Air Reconnaissance and
Observation. — a. The requirements of Calvary differ some-
what from those of the Infantry because of the differences in
the capabilities and limitations of the two arms. Air re-
connaissance for Cavalry usually requires the coverage of
relatively large areas because of —
(1) The greater mobility of Cavalry, particularly of mech-
anized units, as compared with Infantry.
(2) The relative freedom of action, particularly by horse
Cavalry, with respect to roads.
(3) The wide dispersion of cavalry formation and of de-
tachments engaged in reconnaissance.
b. It is essential that personnel operating with Cavalry
have a thorough knowledge of cavalry tactics and objectives,
and that they be familiar with the plans of the cavalry
commander, pertinent to the immediate operation.
■ 79. Army, Corps, or Division Cavalry. — Air reconnaissance
and observation for Cavalry which is operating as an integral
part of an army, corps, or division is furnished by the parent
ground unit. Cavalry commanders initiate requests for such
air missions as are necessary, in cooperation with their units,
53
79-81
ARMY AIR FORCE FIELD MANUAL
and these missions are executed by order of the appropriate
ground force commander through his chief of aviation or
air officer. Air observers normally communicate to the
Cavalry, by radio or dropped messages, all information of
value to the latter in the performance of its assigned mis-
sions. Observation aviation may be attached to a cavalry
unit functioning as part of an army, corps, or division.
■ 80. Cavalry in Independent Action. — Whenever a cavalry
corps or division operates as an independent command, the
requisite reconnaissance and observation aviation normally is
attached and functions under direct control of the cavalry
commander. The aviation attached to an independent
cavalry command must be highly mobile and capable of mov-
ing forward, as the situation requires, to new airdromes
along the line of communication. The location of airdromes
along the line of communication of the cavalry command
facilitates their supply and also their defense from attacks
by hostile ground raiding parties. The types of missions
to be carried out are similar to those performed in coopera-
tion with the Infantry, but the reconnaissance airplane on a
cavalry mission penetrates to greater distances and covers
far more territory than would be the case with an infantry
force of comparable size.
■ 81. Mechanized Cavalry. — a. Continuous air reconnais-
sance and observation is necessary when operating in co-
operation with mechanized cavalry during rapid movements.
The air observer keeps the cavalry commander informed of
the location, strength, composition, and movements of all
hostile forces within the area under observation.
b. The air reconnaissance should extend far enough to the
front and flanks of the advance elements of the supported
mechanized force to give timely warning of the presence,
composition, strength, and movements of hostile forces.
Special objectives of the mechanized force may be located
and kept under surveillance. Air observers cooperating with
mechanized cavalry reconnoiter routes to be traversed and
report obstructions or other conditions which might affect
the conduct of the cavalry mission.
c. The air observer communicates directly with the mech-
anized units by dropped and pick-up messages, by visual
54
AIR RECONNAISSANCE AND OBSERVATION 81-85
signals, or by radio. An advance landing field will be seized
or prepared if cooperation will be improved thereby.
Section VII
COOPERATION WITH SEACOAST ARTILLERY
■ 82. General. — a. The Army Air Forces cooperate with sea-
coast artillery by providing information with respect to the
location, composition, strength, speed, and direction of ap-
proach of naval targets and by reporting the deviations of
the fall of shots from the target. (See PM 4-15.)
b. During night operations, airplane flares may be used
for the illumination of targets. This is particularly impor-
tant in the case of targets which are beyond the range of
shore searchlights. It may be desirable to utilize flares for
the illumination of targets which are within range of the
searchlights, when the use of searchlights might assist the
enemy in determining the location of essential elements of
the seacoast defense installation. The most effective illumi-
nation is obtained by placing the flare within 2° of the
ground observer-target line, about 2,000 yards beyond the
target as viewed by the ground observer, and at an altitude
of approximately 1,800 feet. For tracking where more than
one observing station is being employed, a flare is required
for the observer-target line of each observer. This require-
ment will normally restrict the employment of airplane flares
to distant searching missions. (See par. 251, FM 4-5.)
■ 83. Preliminary Arrangements. — Prior to the execution
of a reconnaissance or artillery adjustment mission, the ob-
server, whenever possible, should confer with the artillery
commander with whom he is to cooperate. It is important
that the method to be employed and the procedure to be fol-
lowed be understood by all concerned.
■ 84. Communication. — The methods of communication be-
tween the observing aircraft and the firing battery employed
upon missions in cooperation with mobile artillery may be
used in conjunction with the firing of seacoast batteries.
■ 85. Methods op Target Location. — a. Maps and charts. —
When accurate and suitable maps and marine charts are
available, the observer may estimate the location of the target
55
85-87
ARMY AIR FORCE FIELD MANUAL
with reference to grid lines, buoys, channel markers, or light-
houses and determine its speed and direction of movement.
The direction is reported by the magnetic bearing of the
course of the target, and its speed is estimated to the nearest
5 knots.
b. Sound ranging. — If available, long range subaqueous
sound ranging apparatus can be used for determining the
target location with sufficient accuracy to get the initial shot
close enough to the target to enable the air observer to
report the deviation satisfactorily.
c. Radio goniometry. — If radio direction finding equipment
is available, radio signals sent out while the airplane is flying
in prolongation of the course of the target can be picked up
by two or more shore stations and the course of the target
plotted. The airplane then flies along the battery-target line
which, when plotted, provides a "fix" from which initial firing
data may be computed. The airplane may, while flying in
prolongation of the course, report the position of the target
with reference to that of the airplane. The observing air-
plane must avoid flying directly over the target or within
range of hostile antiaircraft guns.
■ 86. Observation of Fire. — Airplanes provide the best
means of observation when firing at extreme ranges, or
at shorter ranges when fog banks or smoke screens obscure
the target from shore observation stations. Coast artillery
weapons usually fire at moving targets on water areas with
very few reference points, so the methods used for adjust-
ment of mobile artillery firing at terrestrial objectives are
not altogether applicable. The principal problems of co-
operation with the Coast Artillery Corps are those of com-
munication, target location, and reporting deviations of the
fall of all shots.
■ 87. Reporting Fall of Shots. — a. Methods employed. —
Deviations of the fall of shots may be reported with reference
to the battery- target line; with reference to a north-south
or east- west line through the target; or by means of the so-
called "clock system."
b. Battery-target line method. — The battery-target line
method normally is used at short ranges in connection with
terrestrial position finding and subaqueous sound ranging.
56
AIR RECONNAISSANCE AND OBSERVATION
87
This method is not suitable for use in connection with air-
plane observation of fire at extreme ranges except under
conditions of good visibility. When reporting the fall of
shots by means of this method, the magnitudes of deviations
are reported both over or short and right or left with ref-
erence to the battery-target line.
c. Directional line method. — The reporting of deviations
with reference to a north-south or east-west line is difficult
unless fixed landmarks, visible to the observer, are available
for purposes of orientation. The magnetic compass in the
airplane is unstable during maneuvers which may be re-
quired at the time of the fall of shots and cannot be relied
upon as the sole means of orientation when turns have to be
made at frequent intervals. A gyro turn indicator is there-
fore required. It must be checked against the magnetic com-
pass at every opportunity to insure prompt correction of
precession.
d. Clock system. — When using the clock system the ob-
server superimposes an imaginary clock face over the target.
The line 12 o'clock-6 o'clock passes through the vessel longi-
tudinally with the bow at 12 o'clock. This method is suitable
for either short or long range firing and does not require
reference to any orientation point or line outside of the
le
|»— cot'-
Figure 12. — Clock system.
target vessel itself. Knowing the approximate over-all length
of various types of vessels, the observer can use the length of
the target as a reference scale by means of which the mag-
nitude of the errors may be estimated. Deviations are re-
ported in yards and with reference to clock directions.
57
87-91
ARMY AIR FORCE FIELD MANUAL
Example: Shots falling at locations A, B, and C in figure 12
are reported as follows:
Shot A, 200 yards at 11 o'clock.
Shot B, 300 yards at 2 o'clock.
Shot C, 200 yards at 9 o'clock.
The location of the fall of each shot is reported with refer-
ence to its deviation from the center of the target.
■ 88. Classification of Fire. — The fire of seacoast batteries
at naval targets may be divided into two classes —
a. Trial fire. — Trial fire is employed until the center of
impact is properly adjusted to secure effective fire against
the target.
b. Fire for effect. — Fire for effect is conducted for the pur-
pose of destroying the target.
■ 89. Adjustment. — The observer reports the deviation of
each shot or of the center of impact of each salvo observed
to the plotting room of the battery, from which point the
fire is controlled. The observer continues to report until the
target is destroyed or until another mission is assigned.
Section Ami
COOPERATION WITH ARMORED AND MOTORIZED
FORCES
■ 90. Organization. — a. Aviation requirements. — Armored
forces operating either offensively or defensively require ex-
tensive reconnaissance and observation from supporting avi-
ation. For the efficient conduct of these forces this service
must be rapid and timely.
b. Mobility. — The aviation units supporting armored forces
must be capable of shifting airdromes at rates up to 200
miles per day while maintaining the requisite capacity for or
promptness in executing missions. Special equipment is re-
required to facilitate and expedite this movement and the
establishment of successive operating airdromes. To in-
crease the mobility of the aviation units, the equipment
provided should be kept at the minimum required for self-
sustaining operations.
■ 91. Missions. — a. The types of missions performed are in
general the same as for Infantry and Cavalry. However,
58
AIR RECONNAISSANCE AND OBSERVATION 91-92
they are more frequent, employ a different technique, cover
larger areas, and require greater speed in execution. The
situation moves so rapidly over such a wide area that more
than one airplane executing the same type of mission simul-
taneously is sometimes necessary. When speed of execution
is demanded by the situation, the air commander often makes
and transmits immediate decisions as to the disposition of
airplanes when he is in the air without reference to his ground
headquarters. It is imperative that information gathered on
missions, with the possible exception of distant reconnais-
sance, be transmitted to the armored force commanders prior
to landing. Written reports of the results of route reconnais-
sances, artillery, and liaison missions are seldom formally
prepared and furnished to the armored forces. Continuous
contact must be maintained with armored force advance ele-
ments on the ground. This necessitates prompt mutual iden-
tification and suitable methods of rapid communication, air-
ground and ground-air.
b. The rapidity of armored force operations may frequently
require that combat aircraft perform the dual role of recon-
naissance and attack during a single flight in order to insure
timely support in fast moving situations.
■ 92. Types of Missions. — a. Route reconnaissance. — Com-
manders of armored forces require information as to condi-
tions of roads, bridges, denies, and general terrain many miles
away in order to guide their fast moving columns. Unex-
pected "turn-arounds" are at best costly in time and effort
and tend to spread confusion and lower morale. Ground
reconnaissance elements cannot always obtain this type of
information sufficiently in advance. Moreover, general in-
formation from the air will greatly help the armored force
commander in directing his ground reconnaissance elements
in the right directions, avoiding unnecessary detailed recon-
naissances of impassable routes. The information desired by
the armored force commander must be timely and frequent,
otherwise a bridge may be destroyed or a defile blocked be-
tween the time the reconnaissance is made and prior to the
arrival of the advance guard of the armored force.
b. Distant reconnaissance. — This mission is executed for the
purpose of informing the armored force commander and
keeping him informed of the presence, absence, movements,
59
92-93
ARMY AIR FORCE FIELD MANUAL
and activity of hostile forces, particularly mobile forces, in
certain areas and localities. When operating in enemy terri-
tory or when enemy mobile forces can reach the friendly
territory within which the armored force is operating, this
type of mission is practically mandatory for successful opera-
tions. It will be found, however, that this type of mission
may at certain times and in some situations be combined
with route reconnaissance missions, thereby conserving the
aviation reconnaissance forces. Contact with enemy mobile
ground forces may be maintained by tracking them to deter-
mine their movements, bivouacs, and concealment areas. In
the absence of orders to the contrary, endeavor should be
made to conceal the presence of tracking aircraft from the
ground forces being tracked by remaining behind at the
maximum limit of visibility, by taking advantage of the
up-sun position, and by leaving the vicinity of the force
being tracked for limited periods.
c. Liaison. — Although all ground commanders are concerned
with the position and location of their commands when they
are on the march, the problem of the armored force com-
mander in establishing and maintaining this liaison is a
serious one. Routes of march and movement of the armored
force, combined with the fact that much of its maneuvering
will be in the presence of enemy mobile forces or within ter-
ritory controlled by the enemy, make aviation practically
the only means available for this purpose. The armored
force commander may frequently find it advantageous person-
ally to direct the movements of his forces from the air.
d. Artillery missions. — In cooperating with the armored
force artillery, definite preliminary arrangements are seldom
possible, and such missions are frequently assigned to air-
planes already in the air. Otherwise, these missions are
similar to those executed in cooperation with artillery, in-
fantry, and cavalry divisions.
■ 93. Communication. — a. Armored forces use very little wire
communication even in the artillery. Due to the rapidity
of movement, main reliance must be placed on radio and sup-
plementary means. Their observation aviation units must
depend more on radio than similar units supporting infantry
and cavalry organizations in spite of the greater distances
60
AIR RECONNAISSANCE AND OBSERVATION 93-94
involved. Transmission of important messages by either
voice radio or by radiotelegraph in the clear may be author-
ized by the armored force commander in a fast moving sit-
uation. Efficient communication not only between air and
ground but also between airplanes is absolutely essential to
the conduct of successful operations.
b. The radio station of the aviation unit intercepts and
records all messages between the air and the ground. If
required on account of the distances involved, a radio relay
station is established. The intelligence section of the unit
utilizes these intercepted messages to keep the situation map
up to the minute.
■ 94. Motorized Forces. — The above-stated procedures re-
garding cooperation with armored forces are applicable also
to cooperation with motorized forces, when they are maneu-
vering in motors, although in a somewhat lesser degree. When
motorized infantry and cavalry detruck and fight on foot or
mounted, the procedures for cooperation with Infantry and
Cavalry apply.
61
INDEX
Paragraph
Page
Accuracy of reports
22
13
Adjustment of fire :
Mobile artillery
71—76
50
Seacoast artillery
89
58
Aerial :
Gunner
69
49
Photographs for infantry missions
60
45
Air:
Area definition
2
1
Attack support
48-53
38
Observer _ _ -
73
51
Officer :
Division-- __ _
72
50
Ground forces
81
54
Reconnaissance. (See Reconnaissance, air.)
Aircraft :
Carrier-based _
47
37
Characteristics :
6
2
Reconnaissance.
6
2
Airdromes :
26
15
Camouflage
27
15
Location __ — - - —
80
54
26
15
Visibility at night- -
21
11
Air-ground liaison code of signals- . _ _ —
66
49
61
45
27
15
Altitude:
Affecting air reconnaissance and observation —
14
7
20
10
13
7
Armored and motorized forces, cooperation with
90-94
58
Army :
6
2
Cavalry - -
79
53
Reconnaissance missions
57
43
9, 19
4, 10
Artillery :
64
Fire information - _
48
Mission :
72
50
2
4
71
50
Observation aviation provided with equip-
ment
6
2
Mobile, adjustment of fire-- - -
71-76
50
Relaying of pyrotechnic signals to communi-
48
cate with
65
Seacoast, cooperation with.
82-89
55
Visibility of, at night- . .- -
21
11
Aviation requirement, armored forces- _
90
58
63
INDEX
Paragraph Page
Battery-target line method of reporting fall of
shots 87 56
Bearing, line of, use of term 33 18
Bivouacs, visibility at night 21 11
Camera, focal length 14 7
Camouflage 27 15
Cavalry:
Army, corps, or division 79 53
Cooperation with 77-81 52
In independent action 80 54
Mechanized 81 54
Requirements for air reconnaissance and ob-
servation 78 53
Charts, use in cooperation with seacoast artillery 85 55
Cnlef of aviation:
Corps or army 72 50
Orders through 79 53
Circle, position 33 18
Classification of fire of seacoast artillery 88 58
Clock system of reporting fall of shots 87 56
Clouds:
Affecting observation 10 5
For security 25 14
Coast artillery, reference 86 56
Columns, visibility at night 21 11
Combat:
Aviation, reconnaissance 7 3
Units required to obtain information 29 17
Communication 24 13
Armored forces, characteristics 93 60
In cooperation with seacoast artillery 84 '55
Methods in artillery missions 74 51
Net 26 15
Contact 46 37
Convoy patrol 42 36
Cooperation with —
Armored and motorized forces 90-94 58
Artillery 71-76 50
Cavalry 77-81 52
Seacoast artillery 82-89 55
Corps:
Cavalry 79 53
Reconnaissance 58 43
Counterreconnaissance, enemy 8,56 3,42
Courses, scouting 33 18
Cover, ground, as affecting air reconnaissance
and observation 12 6
Creeping line ahead 43 36
Cross-over patrol 40 32
Darkness :
Affords security 15, 25 8, 14
Reconnaissance and observation affected by 9 4
Daylight 9 4
Defenses, antiaircraft, visibility at night 21 11
Definitions 2 1
64
INDEX
Paragraph Page
Departure, line of 33 18
Distance, scouting 33 18
Distant reconnaissance missions 56-58 42
Dropped messages. (See Messages, dropped.)
Dust as affecting observation 10 5
Endless chain patrol 41 33
Enemy counterreconnalssance 56 42
Escort fighters, support by 15 8
Pall of shots, reporting 87 56
Field, advanced landing 81 54
Fighters, escort, support 15 8
Fire:
Adjustment for mobile artillery 71-76 50
Artillery, information of, during infantry
mission 64 48
Classification of seacoast artillery 88 58
For effect, of seacoast artillery 88 58
Observation of:
Airplane 71-76 50
In cooperation with seacoast artillery 86 56
Trial, of seacoast artillery 88 58
Flares:
Beacons for attacKing units 50 38
In night operations in cooperation with sea-
coast artillery 82 55
To illuminate targets for support of air attack- 52 40
Use for night reconnaissance or observation 15 8
Fog as affecting eye and camera of air observer 10 5
Forces, ground, air reconnaissance and observa-
tion for 54-94 42
Front lines:
Location of friendly 61 45
Visibility at night 21 11
Front, scouting 33 18
Functions, tactical, of air reconnaissance and
observation operations 3-7 2
Formation, reconnaissance and observation air-
craft operating in 15 8
Goniometry, radio 24 13
Method of target location in cooperation with
seacoast artillery 85 55
Ground forces, air reconnaissance and observa-
tion for 54-94 42
Guidance for support of air attack 50 38
Gunner, aerial 69 49
Gyro turn indicator 87 56
Haze as affecting observation 10 5
Illumination - 9 4
Artificial :
Night photography 9 4
Orientation 10 1°
Flares 16 9
65
INDEX
Illumination — Continued.
Targets : Paragraph Page
In cooperation with seacoast artillery 82 55
Support of air attack 50, 52 38, 40
Independent action, Cavalry in 80 54
Infantry missions 54-67 42
Information :
Furnished observer by infantry commander 62 47
Nature 23 13
Of artillery fire during infantry mission 64 48
Operating, for air commanders 28 16
Required by infantry commander 63 47
Securing for air force aviation 31-47 17
Interval, scouting 33 18
Landing field, advanced, to be seized by mech-
anized cavalry 81 54
Liaison :
Between artillery and air observer 73 51
Missions 68-70 49
Definition 2 1
Location :
Airdromes along line of communication of
cavalry 80 54
Friendly front lines 61 4.5
Targets :
Artillery missions 75 52
Methods in cooperation with seacoast artil-
lery 85 55
Maps, use in cooperation with seacoast artillery 85 55
Marker panel for location of friendly front lines. 61 45
Mechanized cavalry . 81 54
Messages :
Dropped:
Air observers use to communicate with
Cavalry 79 53
Confirming radio message relaying pyro-
technic signal 65 48
Location of friendly front line reported by_ 61 45
Use on artillery missions 74 51
Dropped and pick-up, air observer communi-
cates with mechanized cavalry by 81 54
Panel and pick-up 62 47
Pick-up, use on artillery missions 74 51
Preparation 67 49
Methods :
Communication in artillery missions 74 51
Search 36-43 22
Target location in cooperation with seacoast
artillery 85 55
Mission of air reconnaissance for air force aviation. 30 17
Missions 4 2
Armor-ed forces:
Characteristics 91 58
Types 92 69
Army reconnaissance 57 43
66
INDEX
Missions — Continued. Paragraph Page
Artillery 71 50
Assignment of artillery 72 50
Battle reconnaissance:
Altitude ______ 20 10
Security 2 5 14
Close reconnaissance, altitude for 20 10
Contact:
Airplanes on 25 14
Securing information for air force aviation. 46 37
Definitions of various kinds 2 1
Infantry 59-67 44
Liaison 68-70 49
Observation aviation provided with equipment
for certain 6 2
Photographic, flown at greater altitude than
Visual 20 10
Reconnaissance :
Corps and division 58 43
Distant and close 56-58 42
Securing of information for air force avia-
tion 44 36
Surveillance 45 37
Tracking 47 37
Mobile artillery, adjustment of Are 71-76 50
Mobility, armored forces 90 58
Moonlight as affecting reconnaissance and observa-
tion 9 4
Motorized forces, cooperation with 94 61
Natural Illumination, use of term 9 4
Naval targets, Air Corps cooperates with seacoast
artillery with respect to 82 55
Navigators in attacking units, reconnaissance per-
sonnel used as 50 38
Night:
Aerial photography, results with artificial
illumination 9 4
Air reconnaissance, corps and division 58 43
Operations 21 11
In cooperation with seacoast artillery 82 55
Photography, orientation essential 19 10
Reconnaissance for security 25 14
Sea search 9 4
Tracking 47 37
Objectives:
Developing, for support of air attack 31-47 17
Visibility 11 6
Observation :
Aircraft, characteristics 6 2
Aviation attached to Cavalry 79 53
For ground forces 54-94 42
For mobile artillery 71-76 50
Of fire, in cooperation with seacoast artillery__ 86 56
Teams, air 17 9
Observer, air 73 51
Operations 16-28 9
67
INDEX
Paragraph
Panels for location of friendly front lines 61
Parallel search , 36
Radial 38
Patrol. (See Search.)
Performance of command missions 70
Photograph, air, use by observer to report artillery
targets 71
Photographic missions flown at greater altitudes
than visual 20
Photographs :
Aerial, for infantry missions 60
Of results of attack 53
Scale influenced by altitude 14
Show crushing of vegetation 12
Sterescopic study 44
Supplement visual observation 11
Taken on reconnaissance missions for securing
information for air force aviation 44
Photography:
Night aerial, results with artificial Illumina-
tion 9
Night, orientation essential for 19
On corps and division missions 58
To locate artillery targets 75
Pick-up messages. (See Messages, pick-up.)
Plans, familiarity with 18
Point of origin 33
Position circle 33
Preparation of messages 67
Purpose:
Air reconnaissance for air force aviation 29
Liaison missions 68
Reconnaissance and observation aviation 4
Pyrotechnic signal, calling for panels 61
Pyrotechnic signals used on Infantry mission 65
Radial-parallel search. 38
Radial search 37
Radio-
Communication :
Air observer with Cavalry 79, 81
During operations 24
On artillery missions 74
Goniometry as method of target location in
cooperation with seacoast artillery 85
Reception affected by rain and falling snow 10
Radius of visibility 33
Rail transportation, visibility at night 21
Ranging, sound, as method of target location in
cooperation with seacoast artillery 85
Reconnaissance :
Air:
Factors affecting 8-15
For air force aviation 29-53
Night - 58
68
INDEX
Reconnaissance — Continued. Paragraph Page
Aircraft, characteristics 6 2
For ground forces 54-94 42
Army, missions 57 43
By combat aviation 7 3
Mission, definition 2 1
Missions :
Battle:
Altitude 20 10
Security during 25 14
Corps and division 58 43
Distant and close 56-58 42
For securing information for air force avia-
tion 44 36
Personnel used as navigators in attacking
units 50 38
Registration of artillery Are 71 50
Reporting fall of shots in cooperation with sea-
coast artillery 87 56
Reports, accuracy ^ 22 13
Results of attack, determination 53 41
Retirement, line of 33 18
Return, line of 33 18
Scope of manual 1 1 1
Scout 33 18
Scouting terminology 33 18
Sea areas, search of 32 17
Seacoast artillery, cooperation with 82-89 55
Search:
Convoy patrol 42 36
Creeping line ahead 43 36
Cross-over patrol 40 32
Endless chain patrol 41 33
Factors affecting... 34 20
Methods 35 21
Night sea 9 4
Of sea areas 32 17
Parallel 36 22
Radial 37 25
Radial-parallel 38 29
Sea, altitudes 14 7
Square 39 32
Terminology 33 18
Searchlights, shore 82 55
Security :
Affecting air reconnaissance and observation 8, 15 3, 8
During operation 25 14
Of airdromes 26 15
Self-illuminated, use of term 9 4
Shots, reporting fall 87 56
Signal. (See Airplane; Pyrotechnic; Visual.)
Smoke as affecting observation 10 5
Sound ranging 85 55
Square search 39 32
69
INDEX
Paragraph Page
Stereoscopic photographs 11, 44 6, 36
Subaqueous sound ranging 85 55
Sunlight as illumination 9 4
Support :
By escort fighters 15 8
Of air attack 48-53 38
Supported unit, airdromes to be located in vi-
cinity of - 26 15
Surveillance of artillery fire 71 50
System, clock 87 56
Tactical functions 3-7 ' 2
Target location, methods in cooperation with sea-
coast artillery 85 55
Targets:
Illumination 52, 82 40, 55
Location, on artillery missions 75 52
Naval 82 55
Tasks of air reconnaissance and observation for
ground forces 55 42
Teams, air observation 17 9
Telegraph, radio, communication with artillery 74 51
Telephone, radio, communication with artillery 74 51
Terrain :
Characteristics and ground cover _ 12 6
Familiarity with 19 10
Tracking missions 47 37
Trains, visibility at night 21 11
Trial fire of seacoast artillery 88 58
View, angle of 13 7
Visibility:
Factor affecting air reconnaissance and ob-
servation 8 3
Of objectives 11 6
Radius of 33 18
Visual signals 24, 74, 81 13, 51, 54
Weather :
Conditions:
Contribute to security 25 14
Daylight reconnaissance limited 9 4
Data for support of air attack 51 39
Factor affecting air reconnaissance and ob-
servation 10 5
o
70