US AAC/AAF Doctrine: FM 31-35, Aviation in Support of Ground Forces, 1942 - Chapter 3
CHAPTER 3: OBSERVATION AVIATION AND PHOTOGRAPHY
SECTION I: ORGANIZATION AND EQUIPMENT
AIRPLANE TYPES
47. As an aid to an understanding of the organization of observation and photographic aviation, the succeeding paragraphs are devoted to a discussion of their characteristics and equipment.
48. OBSERVATION TYPES.-a. At present there are two basic types of high performance airplanes used for observation purposes: the high performance two-engine multiplace type; and the high performance single-engine, single seater. Both of these types are designed or adapted primarily for observation missions although they may also be capable of air attack. Their speed will be sufficient to permit them to avoid action generally, but they will be sufficiently armed to give them some protection from hostile aircraft and partially armored to afford some protection against ground fire.
b. Liaison type aircraft are characterized by their slow speeds, lack of armor and armament, and by their ability to operate from relatively small areas.
c. Balloons for observation purposes have been discontinued.
49 PHOTOGRAPHIC TYPES.-a. The primary function of a photographic airplane is the transportation of a camera or cameras in operating positions. Several types of aircraft will meet this requirement. Tactical requirements will generally be the determining factors in selection of actual types. These factors will generally be
(1) Altitudes at which photographs are to be taken.
(2) Scales desired.
(3) Security.
b. Correlating these factors with the tactical requirements of photographic squadrons calls for aircraft of maximum speed to operate at high altitudes with operations generally assured by superiority of armament, speed, maneuverability, or altitude. These four conditions complicated by the necessity for carrying cameras cannot all be attained to maximum degrees, therefore a compromise is reached giving the best combination for various conditions, generally speed and maneuverability at altitude, all of which are improved by the lack of armament.
50. MAPPING.-The fundamental requirements for mapping type airplanes are the same as those for high altitude photography with the added requirement of longer range and ability to carry more and larger cameras.
ORGANIZATION
51. GENERAL-Observation aviation will generally be sufficiently decentralized to permit each corps and division to plan the use of and to call direct upon its supporting observation squadron for missions.
52. UNIT ALLOTMENT.-Based on present Tables of Organization the allotment of observation aviation is
a. Theater headquarters--One or more mapping squadrons.
b. Each army-An observation group, consisting of two medium observation squadrons and a photo squadron.
c. Each army corps--An observation group consisting of one medium observation squadron and one light observation squadron per division.
d. Each armored and cavalry corps-One observation squadron (M) and a medium observation group consisting of one medium observation squadron per division.
e. Force Headquarters, Armored Force - One photo squadron.
f. Each separate armored or cavalry division-One medium observation squadron.
53. While generally each echelon depends upon the allotted observation indicated above, higher echelons, where the situation warrants., use their aviation to carry out missions for lower units, normally retaining centralization of control. Armored and cavalry divisions, due to the character of their role and missions, have medium squadrons instead of the light squadrons allotted for the support of infantry divisions.
54. NUMBER OF AIRPLANES.--a. Observation-Each observation squadron has as its basic equipment 18 airplanes of suitable type. These types will vary according to the missions which each type squadron will be expected to perform.
(1) At the present time light observation squadrons have 6 high performance single-engine, single-seater type, and 12 liaison type.
(2) Medium squadrons have 6 high performance bimotor, multiplace type, 6 high performance single engine, single seater, and 6 liaison type.
b. Photo.-Photo squadrons are at present equipped with 6 bimotor, multiplace type, and 12 single-engine, single-seater type.
c. Mapping.-Mapping squadrons will be equipped with 18 long range extreme altitude airplanes as indicated in paragraph 50. Twelve of these are of the bimotor, multiplace type, and 6 single seaters.
FUNCTIONS
55. OBSERVATION.-It is the function of observation aviation to support the ground. units by the execution of reconnaissance, artillery, and liaison missions.
56. PHOTO.-The primary function of photo squadrons is to accomplish all aerial photography required by the army, or armored force to which assigned, except the reconnaissance photography performed by observation squadrons. They will be able to perform a limited amount of mapping, but such functions are not normal and will seriously curtail their normal useful functions.
57. MAPPING.-Mapping squadrons are constituted for the use of theater headquarters to perform mapping in any area which is likely to become of military interest. The services of mapping squadrons will not generally be required by or available to lower echelons as that work will have been previously accomplished. It should be normal to have a mapping squadron assigned to each oversea theater.
SECTION II: OBSERVATION OPERATIONS AND MISSIONS
OPERATIONS
58. LIAlSON.-While the general value of observation aviation is widely recognized, the potentialities and limitations of equipment available, and the standard of training, indoctrination, and morale of personnel must be fully realized by the supported commander in order to exploit his observation aviation to the maximum without excessive losses This calls for very close liaison between the supported commander and the observation aviation available to him. Such liaison is of sufficient importance that the observation unit commander will be designated as air adviser to the commander of the supported unit. He should take advantage of his position, particularly in the initial phases of operation, personally to advise the supported commander on these points. Thereafter he will generally desire to be represented by one of his most experienced officers who will have a very thorough personal knowledge of his particular unit, the commander continuing to act as air adviser to the commander of the supported unit making whatever personal contacts are deemed necessary.
59. INTELLIGENCE.---a. General plan. In order to insure intelligent execution of all observation missions, it is of the utmost importance that every pilot and observer be familiar, with the general scheme of maneuver of the supported unit and with the details of every operation in which he may be called upon to participate. The plan of employment of other friendly operations both ground and air should be known to planning personnel to insure coordination. Close contact should be maintained with adjacent air units to permit rapid exchange of information vital to their operations.
b. Enemy situation-It is important that pilots and observers keep posted on the enemy situation, both ground and air, not only for the intelligent execution of their mission but for their own safety. This knowledge enables them to determine more thoroughly the requirements of their mission than would be possible without it. Their safety is dependent upon their knowledge of the locations of ground installations which might oppose the execution of their mission and enemy air activity which they might desire to avoid.
c. Intelligence officer.-In order to disseminate this information to pilots and observers, the intelligence section of the observation squadron must maintain information which is thorough, accurate, and up to the minute. In order to maintain this condition, it is necessary that the intelligence officer not only thoroughly understand the organization and operation of the supported ground elements, but that he have a general knowledge of the opposing ground forces. He must maintain very close liaison with the supported unit to get all information concerning friendly plans and situations and to keep himself posted at all times on the situations of both friendly and enemy ground forces. He must maintain contact with other air elements and any other sources available for information concerning both friendly and enemy air activity. He must keep all pilots and observers constantly informed of the general plans and situations, and upon request for a mission he must himself analyze it and brief his observation crews immediately prior to dispatching the mission. Upon completion of the mission he must receive all reports and interrogate the crews involved in order to transmit proper intelligence to the supported unit. He must have sufficient relief within his section to maintain constant operations and at the same time permit personal visits to the supported unit.
60. ORIENTATION-It is particularly important that pilots and observers in observation squadrons be thoroughly familiar with the terrain over which they operate in order that they will know at all times where they are, and be able to find their objectives by reference to landmarks while flying at low altitudes with the minimum reference to maps in flight.. Orientation is important in locating and reporting observations. They should make a thorough study of the area beforehand to permit constant orientation without reference to maps particularly during darkness when the minimum number of landmarks are visible.
61. ALTITUDEs-Only general rules can be stated regarding the altitudes at which observation missions can be performed. The most suitable altitude depends upon such factors as: mission, performance and characteristics of the aircraft employed, armor and armament carried, range and effectiveness of hostile small arms fire from ground weapons, amount of effectiveness of antiaircraft fire, hostile air activity, camouflage of the airplane, and weather conditions such as the ceiling, visibility, and clouds. Considering terrestrial combat interference, operations of observation aviation over friendly territory is restricted only by the range depth of fire from hostile weapons on or close to visual front lines. The weapons available to the hostile ground arms, then, will determine dangerous altitudes. Small caliber weapons are generally effective up to 5,000 feet elevation and larger calibers, including heavy antiaircraft weapons, to varyingly high altitudes up to 21,000 feet. Hence, the safest altitudes, considering only ground fire, are those above the largest caliber hostile weapons or below the altitude at which smaller ones may be used effectively. Similarly, while immunity from hostile air attack cannot be assured, safest altitudes are those overtopping the ceilings of hostile aircraft or zero altitudes which prevent hostile diving attacks.
62. SORTIE,- While it would be possible under conditions of absolute air superiority for aircraft to exist above the range of hostile ground fire, such conditions of air superiority would be considered exceptional and of short duration. This imposes the restriction on the ground commander of requiring that he select definite objectives to permit observation airplanes to fly in at minimum altitude and maximum speed for a hasty observation and quick return. The mission of aerial surveillance in the face of even minor opposition should be exceptional.
OBSERVATION MISSIONS
63. GENERAL.-Observation aviation operating in support of ground forces does not replace any of the intelligence agencies available to the commander of those forces, but supplements them and can provide the commander with information which he cannot secure by other means. Corps and division observation units will be trained and equipped for reconnaissance, artillery support, and liaison missions, and for such photographic work as may be required by the supported unit, particularly reconnaissance photography.
The army observation group because of its photo squadron will in addition be equipped and trained to furnish artillery fire control photographs and limited mapping photography.
64. RECONNAISSANCE.--a. Day-Complete control of the air may permit a detailed and deliberate visual reconnaissance of hostile territory by methods similar to those previously employed. However, it must be realized by all concerned that the nature and effectiveness of hostile air action are the controlling factors, and when operating against an enemy of approximately equal air strength, complete control of the air will seldom, if ever, exist. Ground fire and hostile aviation may require the performance of daylight reconnaissance missions in hostile territory at maximum speed either at minimum altitude or at relatively high altitudes. This will limit the effectiveness of visual reconnaissance and necessitate reliance upon photographic and night reconnaissance with a minimum time spent over hostile territory and will also require a careful selection of reconnaissance objectives. Missions will generally be carried out by making a series of brief sorties into enemy territory taking full advantage of high speed using clouds or irregularities of the terrain for cover.
b. Night.-Night reconnaissance is habitual and is productive of a great deal of valuable information, particularly to the experienced observer who is familiar with the terrain.
Normal conditions will sometimes permit, without artificial illumination, the observation of activities which rely for their success upon the cover of darkness, such as troop and supply movements. Artificial illumination may permit closer examination when necessary. Even though information obtained by night reconnaissance may be meager, the moral effect on the enemy is considerable as he will be uncertain as to whether his movements have been discovered. (See FM 1-20.)
65. MISSIONS for INFANTRY-Missions; performed for infantry include the location of the opposing front lines, observation of the progress of combat, location of hostile resistance or enemy penetrations into our positions, and assembly of hostile troops for attack or counterattack. Commanders of all echelons of ground forces are interested in the progress of battle. It is the primary responsibility of the lower units of the ground forces themselves to furnish this information to their commanders. When these agencies prove inadequate, observation aviation may be called upon to assist in obtaining this information. 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. Frequently a single sortie may be able to determine the desired information, in which case the mission should not be burdened with requests for additional reconnaissance.
66. LIAISON missions.-Liaison missions are performed to provide the superior commander with information required in special situations and not obtainable through routine channels, or to transmit information or orders when such transmission can be more effectively accomplished by air messengers than by other means of communication. Where the situation permits, this mission may be performed by the liaison type airplane. However, all concerned must realize that this type airplane is extremely vulnerable to hostile ground and air fire; that normally it must be employed only over friendly territory; and that conditions of modern warfare may not provide a definite line of demarcation between hostile and friendly territory behind which such airplanes can operate. Additionally, while this airplane is designed to operate from small, unprepared fields, the latter may not be available.
67. ARTILLERY missions.-Due to the inability in many cases of ground observers to locate targets and observe artillery fire, aerial observation is necessary. The liaison type airplanes may operate over friendly territory for the adjustment of artillery. Due to its extreme vulnerability, even to ground fire near the front lines, this type airplane must be looked upon more as an elevated observation post rather than an observation airplane for the adjustment of artillery. Enemy air activity will more readily curtail the use of this type airplane than the high performance observation type. With the realization of these factors, observation and artillery units must depend upon the normal high performance observation airplane to some degree for adjustment of fire. Long range artillery fire, defilade, and poor visibility may require that such adjustment be carried out over hostile territory. Proper planning and prearrangement must be thoroughly considered for rapidity of adjustment to reduce to a minimum the time which the airplane spends over hostile territory. The use of suitable fire control photographs aids in such planning. For details concerning tactics and technique employed in artillery missions see.FM 1-20.
68. COOPERATION WITH CAVALRY.-Observation aviation does not replace or supplant Cavalry as a reconnaissance agency, but by proper cooperation increases the effectiveness of that arm by extending its radius of action and by directing attention to known or suspected hostile forces, thereby obviating useless marching and conserving men, horses, and materiel. Observation for Cavalry is particularly important in the initial phases of a strategic or tactical movement. During combat the observation aviation mission. with Cavalry is essentially the same as that with Infantry.
69. COOPERATION WITH ARMORED AND MOTORIZED FORCES.-The rapid movement of armored and motorized units calls for the use of observation aviation for distant and route reconnaissance, march liaison, observation for artillery, and normal liaison. Observation aviation is of vital importance in the operation of armored forces.
70. COOPERATION WITH SEACOAST ARTILLERY.-In the organization of air support commands no observation aviation is specifically provided to serve seacoast artillery but occasions may arise wherein such may be required, in which case it will be provided by the appropriate air support commander as directed by the theater or army commander. Long range reconnaissance at sea for the discovery of targets is beyond the realm of the function of observation aviation operating on such missions, but it may be used for short range reconnaissance and for the adjustment of fire on targets. (See FM 1-20.)
71. COOPERATION WITH COMBAT SUPPORT AVIATION.-On occasion, certain specified observation missions may be authorized to call directly to air support control, to airdromes, or to combat support aviation on air alert, for the purpose of reporting targets for combat support aviation. Observation missions may be dispatched primarily for the purpose of locating such targets. It should be noted that an observation mission authorized to make such requests for combat air support is in the same status as a ground air support party. After it files a request and receives an approval it will, if desired, remain in surveillance until the arrival of the combat aviation which it then "leads in" to the target.
72. Communication Methods,- a. Success of communication in observation aviation depends to a large degree upon constant use of the communication system involved by all personnel concerned. It is not sufficient that individuals be able to use the system but it is vitally important that all parties who are to communicate with one another constantly train and practice as a team. It must be recognized by commanders that responsibility for each complete communication system must be centralized rather than divided. Methods which necessitate cooperation between aircraft in flight and troops on the ground require constant practice and coordination to give any expectation of the success which will be necessary in operations.
b. There are a variety of methods of communication available to the observation team and ground units with which it is operating. Radio, while it is the most widely used, cannot always be considered reliable and must be supplemented by other means.
(1) Radio.-Radio is the normal means of communication for observation missions with artillery, armored forces, and combat support aviation and is relied upon generally in operations with other forces, particularly in higher echelons.
(2) Dropped messages.- The dropped message is an important and reliable means of communication which is particularly useful to deliver marked maps, photographs, or sketches, none of which can be transmitted by radio. This means may be used frequently on reconnaissance missions with more satisfactory results than radio; for communication with ground troops who have no other means available; to supplement radio on many missions; and as a satisfactory emergency means on others.
(3) Panels.-Simple prearranged codes may at times permit the use of panels as a valuable means of communication when others would not be practicable. Their use should be limited to single indicators as even moderately long messages are too time-consuming to be considered. They may be of particular value in special operatons such as those undertaken by parachute troops or detached raiding parties.
(4) Pyrotechnics.-These may sometimes be used for communication or identification.
(5) Airplane maneuver signals.--Simple signals may sometimes be transmitted by maneuvering the airplane in accordance with a prearranged code. Their primary use is for artillery missions but may be adapted to other uses.
(6) Pick-up messages-Messages may be picked up by liaison type airplanes but such is not generally practicable with high performance type aircraft.
(7) Miscellaneous.-Frequently the most satisfactory and rapid procedure for reconnaissance missions will be to require that the observation team land at the end of a sortie to deliver photos for processing and to be interrogated by intelligence officers.
SECTION III: PHOTOGRAPHY AND MAPPING
PHOTOGRAPHY
73. GENERAL. (See FM 1-35, 21-27, and 30-20).--a. Aerial Photography cannot of itself win tactical advantages, but the failure to use aerial photography properly may result in the loss not only of battles but of a war. Aerial photography forms the basis for a large part of all intelligence. It is therefore essential that air and ground commanders have a clear idea of the capabilities and limitations of aerial photography.
b. A major use of aerial photography in an active theater is to secure information for the purpose of intelligence. It should be the normal custom for these same photographs to be used for terrain studies and map correction. However, the vital function is to provide information, either positive or negative, concerning the location and extent of enemy installations, supplies, vehicles, and troops.
74. DISTRIBUTION OF AERIAL PHOTOGRAPHS.-All intelligence data, and particularly those obtained from aerial photographs, are of maximum value to the supreme commander and of diminishing value to his subordinates. However, to insure proper distribution in the minimum time, photographic units must distribute the information gained by aerial photographs to all interested headquarters simultaneously and not through the normal chain of command. The bulk of the photography will be primarily for intelligence purposes and the photographs themselves will not receive wide distribution. Furthermore the speed of production of aerial photographs is directly proportional to the number of prints made from each negative. If qualified liaison officers from the supported units are stationed with the photographic squadron of the command or with the G-2 with which that squadron operates, they may indicate the need for distribution of specific photographs to their units. It is the duty of these liaison officers to determine which of existing aerial photographs should be distributed to their units. It will usually be far more desirable to authorize the liaison officers to indicate the distribution desired in each particular instance, rather than set up hard and fast distribution. These liaison officers, being familiar with the immediate needs of their units, may also serve as a channel for the request for aerial photography.
75. OPERATIONS.-a. Day.-The performance of required aerial photography during periods when there is friendly control of the air presents no particular problem other than that presented by the weather. However, it must be constantly borne in mind by supported units that, in the face of active enemy aerial opposition, it is suicidal to attempt to photograph a specific objective at regular intervals. Photographic aviation will depend upon speed, altitude, and the element of surprise in order to secure desired photography in the face of strong opposition. The office in charge of photographic operations must employ a great deal of ingenuity in avoiding any pattern in photographic flight over specific areas. It is quite practical to secure a strip of photographs of enemy area, utilizing surprise, speed, and extreme altitudes. It is thus possible, by careful planning of successive photographic flights undertaken primarily for intelligence photography, to secure overlapping coverages of wide areas.
b. Night.-A general exposition of night aerial photography is found in FM 1-35. Excellent results are produced with artificial illumination under good visibility conditions although only a small area is covered with success, dependent upon the degree of accuracy in locating the desired area.
c. General.-Orders for photographic missions must be specific. At the altitudes at which missions are generally conducted in the face of active opposition, the photographic pilot cannot observe troops or installations upon the ground and then secure photographs. Instead, photography must be obtained on a specific strip of terrain without regard to the pilot's ability to see enemy installations, troops, etc. Photography secured in this fashion is capable of giving negative information as well as positive. While it is possible for a clever and ingenious enemy to camouflage and conceal his actions from visual observation, the camera cannot be fooled, particularly when a resultant photograph is studied by highly trained photographic interpreters.
MAPPING
76. MAPPING SQUADRONS.-Special mapping squadrons are constituted for the use of theater headquarters. (See pars. 47-57.) They normally perform the mapping of large areas. Their operations should be planned to cover all areas of possible military action to permit the production of accurate maps as far in advance of the needs of the troops as practicable. In order to provide for maps or for map revision a mapping squadron will normally be provided for each oversea theater. Proper anticipation of mapping requirements will generally permit greater coverage with more satisfactory results without enemy opposition than is possible under conditions of actual hostilities.
