ICAG Tactical School - US AAC/AAF Doctrine: FM-15, Air Fighting, 1942 - Part 2

CHAPTER 5: EMPLOYMENT OF PURSUIT AVIATION

        I. General --------------------------------------- 26--29

        II. Methods Of pursuit defense --------------------- 30-32

        III. Pursuit aviation in local defense ---------------- 33-39

        IV. Pursuit aviation in general defense -------------- 40-48

        V. Interception ------------------------------------ 49-55

        VI. Technique of interception ---------------------- 56-60

        VII. Support of air striking forces -------------------- 61-62

        VIII. Support of ground forces ------------------------ 63-67

        IX. Pursuit in night operations --------------------- 68-71

SECTION I: GENERAL

26. MISSION OF PURSUIT.-The mission of pursuit aviation is to deny to the hostile air force freedom of action in the air.

27. Denial OF FREEDOM of ACTION.-The denial of freedom of action to enemy air forces is accomplished in three ways:

a. Destruction.-Total destruction of the enemy formations by offensive action in the air, thereby depriving the enemy of weapons with which to continue air warfare.

b. Attrition.-Reducing the enemy air forces by casualties in air combat to such an extent that

(1) Their operations become expensive in personnel and materiel;

(2) Their morale is lowered; and

(3) Their will to continue air warfare is adversely affected.

c. Threat.-The mere fact that pursuit forces are present and are likely to attack at any time within their operating zones will limit the freedom of action of the enemy in those zones. This threat causes the enemy to carry defensive armament which reduces the load of offensive weapons or fuel, or both. Furthermore, it requires the enemy to fly in large formations for mutual support, thereby reducing their freedom to maneuver and restricting the number of targets that might otherwise be attacked.

28. CONTROLLING FACTORS.-The conduct of the pursuit forces in the execution of their mission is predicated upon the operations of the hostile striking forces. The disposition and size of pursuit units within the limits of the capacity of the force are dependent on many factors, chief among which are -

a. Extent of the area over which operations are to be conducted.

b. Method of operation of hostile striking forces.

c. Strength of pursuit force available.

d. Nature, extent, and efficiency of the aircraft warning service.

29. SPECIFIC Missions.-Pursuit aviation may be employed in the execution of one or any combination of the following specific missions:

a. Defense of an area or installations.

b. Support of air attack.

c. Support of ground forces.

SECTION II - METHODS OF PURSUIT DEFENSE

30. DEFENSE OF AREA OR INSTALLATIONS.-Pursuit aviation assigned to active air defense operates either in local defense of a single objective or in general defense of an area including many objectives. The type of defense to be provided will depend upon the nature and importance of the objectives requiring pursuit protection, the number of such objectives, their degree of geographic concentration, their locations with respect to frontiers, and the strength of the pursuit force available.

31. LOCAL DEFENSE.-a. Local defense by pursuit aviation is a form of active air defense for a single objective in which the defending pursuit force is limited to operations against hostile penetrations that directly threaten that objective. It is appropriately employed for the protection of vital objectives that are vulnerable to air attack and that cannot be effectively defended by other means.

b. A local defense is the most effective defense for single objectives that are highly vulnerable to air attack.

c. The purpose of local defense is the provision of immediate protection for the defended objective, and the operations of the defensive pursuit are based upon this mission. The greatest disadvantage of such employment is that no objective other than that to which it is assigned is afforded direct protection by the pursuit force. It does, however, provide incidental protection to those installations that are in the immediate vicinity of the defended objective, because of manner of operations by defending pursuit.

32. GENERAL DErENSE.-a. A general defense by pursuit aviation is that which is provided for a specified area or defended sector. It differs from the pursuit employment in local defense in that special security is not provided any particular objective but, instead, some measure of security is provided for all installations and possible enemy objectives, including important troop concentrations or movements, that are distributed throughout the defended area or sector. A general defense is instituted primarily to protect an area containing many undefended or weakly defended objectives.

b. A defended area may contain many objects protected by the local defense of antiaircraft artillery or pursuit aviation, or both. In such instances and when possible the pursuit aviation in general defense supports and cooperates with the local defense.

SECTION III -  PURSUIT AVIATION IN LOCAL DEFENSE

33. LOCAL DEFENSE.-a Doctrine.- lnterceptor units, force, or aviation must be so located on the ground or in the air that immediate protection can be afforded the defended objective with the maximum of the available force. All enemy air attack forces must be opposed prior to their assault on the defended objective. No enemy airplane or formation is permitted to conduct an unopposed attack against the defended objective.

b. Aircraft warning service~An aircraft warning service is essential for the employment of interceptor units, force, or aviation in local defense. The effectiveness of the defense is vitally dependent upon the nature and extent of the information provided by the warning service and the rapidity with which it can be transmitted to the interceptor units, force, or aviation. To assure interceptions, an accurate, timely, and continuous flow of information of the approach of hostile air forces must be furnished to the pursuit commander both prior to and after the pursuit leaves the ground to effect interception.

34. Pursuit OBJECTIVES~Pursuit aviation assigned to a local defense augments such other defenses as may be present. The pursuit force is employed only against forces that threaten the security of the defended objective.

35. COORDINATION OF DEFENSE MEANS-A local defense provides close protection for the objective with all available means. In all cases the defensive forces, air and ground, are disposed and employed in a manner that will give an all-around defense. All hostile air attack forces reaching the objective must be brought under maximum fire during the time of their sighting operations. The enemy force will not only be most vulnerable to antiaircraft artillery and pursuit during this period, but the maximum protection to the defended objective in such circumstances is assured by the influence of defensive fire upon enemy bombing accuracy. The tactical operations of pursuit are influenced by the character and strength of the antiaircraft artillery defenses. The interceptor command must have operational control over all antiaircraft artillery, searchlights, and barrage balloons in the defense area.

36. EMPLOYMENT OF PURSUIT.-Pursuit operations based upon the use of information made available by the aircraft warning service are conducted by the ground alert or air alert methods. In the ground alert method, interceptor units, force, or aviation are alerted on their airdromes, taking off and effecting interception of the hostile attacking force upon instructions and through information transmitted to the air commander by radio. In the air alert method, the interceptor units, force, or aviation are alerted at a station in the air and effect interception of a target through instructions and information received by radio. (For interception procedure see pars. 49 to 55, incl.)

37. GROUND ALERT DEFENSE.-The ground alert method of employing pursuit aviation should be used whenever the aircraft warning service is sufficiently extensive to permit the interception of the enemy force at a point that will allow time for effective air combat prior to the delivery of the enemy assault. In local defense no attempt is made to intercept the enemy at a considerable distance from the objective. The pursuit force maintains a position between the enemy and the defended objective during the approach to interception. Pursuit operating from an alert station on the ground is capable of utilizing all the available combat units against the enemy. For this reason it should always be employed when the warning service can provide information of the enemy approach in sufficient time to insure proper interception. Effectiveness of ground alert defense will vary with the distance between the pursuit alert stations and the objective.

38. AIR ALERT DEFENSE.-In local defense by the air alert method, pursuit takes up an alert station in the air over the defended objective. This method of using pursuit is employed in the local defense of objectives where the extent of the aircraft warning service is less than that required for ground alert defense. This form of defense is exhausting and uneconomical; it should be used only when the area requiring protection is small and when the need for the utmost measure of direct air protection is sufficiently important to justify its use.

39. COMBAT PATROLS.-a. An enemy air attacking force may be intercepted by using a pursuit force for conducting combat patrols over a particular objective or along a line on which it is desired to engage the enemy. The use of combat patrols ordinarily will be confined to the local defense of objectives where no aircraft warning service has been provided, or where the depth of the existing service is insufficient for other methods of employment. For air security the objectives that are located near front lines and frontiers must be defended by patrols.

b. Local defense by combat patrols requires the assignment of defense forces in excessive numbers if effective patrols are to be provided for prolonged periods of time. The method, therefore, should not be employed except in cases where a definite threat to the defended objective is present, and the importance of that objective justifies the diversion of strong pursuit forces to its defense.

SECTION IV -  PURSUIT AVIATION IN GENERAL DEFENSE

40. GENERAL.-A general defense is provided for the purpose of defending a number of objectives that are located within a specified area or defensive sector. It gives security to objectives that have no active defenses, or that are weakly defended, and supports all local defenses within the defended area. Although not as effective as a local pursuit defense in providing security for particular objectives, a general defense can provide a measure of security for many more objectives within a given force than it would be possible to defend by local defense.

41. CHARACTER OF DEFENSE.~. A general defense is an extended defense, consequently the probability of making an interception without the assistance of an aircraft warning service is remote. The distance from the alert station at which pursuit aviation operating with an aircraft warning service is capable of engaging the enemy in combat is determined by the extent of the aircraft warning service, the course flown by the enemy force, the relative performance of enemy and friendly airplanes, the altitude of enemy penetration, and the effect of wind.

b. Pursuit operates in general defense by ground alert, air alert, or patrol methods. Ground alert should be used whenever time and space factors will permit. If the situation precludes the use of ground alert pursuit, air alert, or a combination of air alert and ground alert methods should be adopted. Pursuit patrols are relatively ineffective in establishing a screen to resist enemy penetrations, and are employed only when an aircraft warning service is lacking or is so limited in extent that it does not provide time for effective interception by the air alert method, and the importance of the target makes it imperative that the defended objective be provided pursuit defense.

42. SCOPE of DEFENSE.-The course taken by the enemy force to an objective may be that which requires him to remain within the limits of the aircraft warning service area the minimum length of time. Any other course will ordinarily result in an advantage to the defender, inasmuch as it will allow more time for the functioning of the defense, which may result in the enemy being intercepted farther from his objective and by a larger pursuit force than would otherwise be possible. The location of the line on which the enemy can be intercepted from an alert station will vary with the speeds of the opposing forces and the outer limits of the aircraft warning service.

43. LINE OF RESISTANCE.-For a given set of operating conditions, a line of resistance is the outermost line on which the enemy can be intercepted in a general defense with a given disposition of the pursuit force. The distance to interception from a given alert station will vary inversely with the altitude at which the interception occurs, consequently a line of resistance will advance as the altitude at which the enemy conducts operations is decreased. For all practical purposes, a line of resistance must be established so that a defense can be provided against enemy operations at the highest altitudes from which he can deliver effective attacks. Lines of resistance are used by the pursuit commander in planning a general defense. By means of these lines, the locations of the pursuit forces and the methods of employment are determined.

B 44. EFFECT OF LINES of RESISTANCE.-The location of the line of resistance will determine the limits of the general defense. Defense, however, is not provided for objectives that are on this line, inasmuch as the pursuit forces will not have time to act against the enemy prior to the delivery of his attack. The distance, therefore, of a defended objective from the line of resistance governs the degree of defense that can be provided. A line of resistance does not constitute a barrier that exerts a continuing influence for the defense of all objectives within the line. The defending forces may be avoided by the enemy when he flies through clouds or above clouds or when he conducts operations in darkness. Thus objectives that are located a considerable distance away from the defending pursuit forces may be attacked by the enemy under some conditions with little or no opposition from the general defense. The lines of resistance in a general defense must be located so that maximum defense is given the most important objectives.

45. PLOTTING LINES or RESISTANCE.-a. In order to plot a line of resistance it is necessary to plot the lines of interception from each alert station based on the maximum speeds of opposing aircraft and the depth of the aircraft warning service. Where several alert stations are used to establish a line of resistance, the line will consist of a series of intersecting curves.

(1) Figure 1 (see back of manual) shows a plot of lines of interception for an air alert pursuit force stationed at 10½, 20, 30, 40, and 50 miles within the outer limits of the aircraft warning service; and lines of interception for a ground alert Pursuit force stationed at 52½, 60, 66½, 80, 100, and 150 miles within the outer limits of the warning service. The upper horizontal line of the chart represents the outer limits of the aircraft warning service. The points marked on the center line of the chart represent pursuit alert stations. The various curves indicate the limits at which interceptions may be expected with pursuit stationed at those alert stations under the conditions assumed.

GRAPHIC AUS DEM ENDE

(2) If figure 1 is drawn to the scale of a working map, it is possible to place the upper horizontal line on the general line representing the outer limits of the aircraft warning service, measure the distance from that outer limit to any alert station being considered, and determine how many places on the map can be afforded a defense from that alert station. The center line of the chart should be kept at right angles to the general line representing the outer limits of the aircraft warning service.

(3) If the outer limit of the aircraft warning service is not on a straight line but is, instead, in the form of a salient, then two curves should be drawn to indicate the line of interception. Place the proper point representing the alert station on the chart over that station on the map; swing the right-hand curve about that pivot until the center line is at right angles to the general line representing the outer limit of the aircraft warning service to the right of the alert station. Draw an arc on the map showing the line of interception to the right of the alert station. Next swing the lefthand curve about the alert station as a pivot until the center line is at right angles to the general line representing the outer limit of the aircraft reporting net to the left of the alert station, and draw an arc on the map showing the line of interception to the left of the alert station.

b. By following a procedure similiar to that outlined above, the pursuit commander should be able to dispose his forces in a manner that will provide for the most effective general defense of that area.

46. CONDUCT or DEFENSE.-a. Conduct of air striking forces.-The enemy may be expected to concentrate his offensive operations in a manner that will prevent the use of the majority of the pursuit defenses at any one time. By attacking all of the objectives within one sector simultaneously he need be concerned only with the pursuit forces in that sector. Areas that are unlikely to be covered effectively with an aircraft warning service, such as large bodies of water, swamps, or other terrain unsuitable for such installations, will offer favorable avenues of approach.

b. Defending pursuit limitations.-Defending pursuit forces must be prepared to resist enemy air operations regardless of where or when they occur. However, the combat endurance of the pursuit forces that can be brought to bear on a line of resistance at any one point may soon be exhausted, and the delay occasioned by the necessity of refueling and rearming these forces may leave a temporary gap in the defenses. Thus the inherent inefficiency of the pursuit defenses as a whole is apparent in the application of the general defense.

c. Defense in depth.-It is unlikely that a general defense can be provided that is strong enough to oppose successfully an enemy penetration in force at the outer limits of the defended sector. When sufficient force is available, the defense must be organized so that increasing resistance becomes possible as the depth of the enemy penetration increases. Where successive penetrations are made at the same point in a line of resistance, alerted pursuit forces covering other approaches may be employed to engage the enemy within the defended sector even at the expense of weakening the defense against penetrations at other points.

d. Necessity for defense mobility.-The pursuit forces available may be concentrated to cover the logical routes of enemy approach. Where the enemy is effectively opposed at these points he will undoubtedly select other routes of approach. A mobile general defense should be provided to meet such contingencies. Where satisfactory operating facilities are available, the mobility of pursuit will permit the character of the defense to change radically from day to day. A force that is concentrated and moved daily from point to point may result in the enemy receiving unexpected resistance, and thus cause him to resort to measures for security that he would not otherwise undertake.

47. INFLUENCE OF LOCAL DEFENSES ON GENERAL DEFENSE. Local pursuit defenses provide incidental defense to all objectives within the immediate vicinity of the defended objective. There is no certain method of determining which objective an enemy is about to attack. In local defense an enemy that threatens to attack is engaged at a limited distance from the defended objective. This distance will depend upon the depth of the aircraft warning service and the location of the alert stations. Within Its zone of operations a local pursuit defense will reinforce the general defense by resisting enemy Penetrations to the interior area. The enemy is unlikely to fly a course over objectives that may have local defenses when it is possible for him to avoid them. This fact should be considered in planning the general defense.

48. DISPOSITION OF PURSUIT DEFENSES.-The disposition of the pursuit defenses within an area will vary with the enemy capabilities; the size of the area; the size of the pursuit force available; the relative location of the area with respect to other defensive areas; the character and extent of the aircraft warning service; the availability and location of operating airdromes; and the number, character, and location of the objectives within the sector that cannot be provided adequate security by other means of defense. If an adequate local defense could be furnished for all important objectives there would be no need for general defense. Inasmuch as this condition probably will not be realized, a general pursuit defense usually will be necessary. With limited pursuit forces, the assignment of pursuit to local defenses, although greatly increasing the security of individual objectives, will decrease the security of other objectives within the sector.

SECTION V: INTERCEPTION

49. GENERAL.-a. In order to alert pursuit defense units and effect interception of hostile aircraft penetrating a defended area, information of the approach and progress of the enemy is necessary. The technique of interception for either local or general defense is similar except that in general defense no restriction is placed on the allowable distance at which interceptions are made whereas, in local defense, operations are limited to the immediate vicinity of the defended objective. The technique of interception in local defense is described below.

b. Information required by the pursuit force commander in order to intercept and attack a hostile air force include

(1) What.-Type, strength, and disposition of hostile aircraft.

(2) Where.-Location, altitude, direction of flight, and speed of the enemy.

(3) When.-Time of the observation.

50. OBSERVATION STATIONS.-A continuous watch must be kept in a large area surrounding the defended objectives. Such a watch performed by airplanes on patrol would require the use of an enormous number of aircraft which would consequently not be available for combat use. Therefore, a net of ground observation stations must be established about the defended objective.

51. EXTENT OF WARNING SERVICE.-The distance to which the net of observation stations must extend outward from the airdromes of defending pursuit forces is governed by time and space factors. These in turn involve the time required for the transmission of information, operation and movement of the defending pursuit forces, air combat, and for the movement of the hostile aviation force.

52. DESIRED LINE OF INTERCEPTION.-. The technique of interception is based upon the requirements that friendly aircraft intercept the enemy aircraft while the latter are still at a distance from the objective. In local defense the line connecting points at which interception is desired is called the "desired line of interception" and is abbreviated and referred to as the "desired L. I." A schematic presentation of a defended objective and the desired L. I. about that objective are shown in figure 2.

b. The distance (shown in fig. 2 as d) from the defended objective to the desired L. I. Is governed by the desired "combat time" of the defending pursuit and by the speed of the enemy aircraft. The combat time is the period required for the effective delivery of fire by the intercepting aircraft and varies with aircraft of different characteristics and with different situations. For any particular aircraft the combat time will not vary between wide limits, and an estimated average time for the effective delivery of the entire fire load carried constitutes a satisfactory basis for purposes of computation.

c. The distance from the defended objective to the desired L. I. is determined by computing the distance the enemy aircraft will travel during the combat time. Information of the performance of enemy aircraft will usually be available. By assuming the enemy speed to be the highest which can reasonably be expected, a safe basis for computation is assured. Assuming a situation in which the combat time is 10 minutes and the enemy speed is 240 miles per hour, the desired L. I. would be 40 miles from the defended objective. Under the conditions stated, d in figure 2 would be 40 miles.

53. POSSIBLE LINE OF INTERCEPTION.--a. (1) The location of the base from which the defending pursuit operates is important in its relation to the location of the defended objective. Aviation forces may operate with equal facility in all directions from a base. The line to which an aviation force can go in a given length of time in still air will be a circle whose center is the base. This circle is called the "possible line of interception" and is abbreviated and referred to as the "possible L. I."

(2) When wind is present the possible line of interception will vary with directions of approach. In practical operations the presence of wind will be normal. For this reason solutions for the possible line of interception for specific operations will always require the application of wind speed and direction factors.

b. The relation between the base and the defended objective and the relation between the possible L. I. and the desired L. I. are shown in figure 3. The desired L. I. should lie on or in the possible L. I. The minimum requirement is met when the possible L. I. is tangent to the desired L. I. at a point in prolongation of the line: base-defended objective. The only condition under which the possible L. I. and the desired L. I. coincide occurs when the base is the defended objective, or when the base lies over or within the defended objective.

54. ALTITUDE of INTERCEPTION-a. (1) The defending pursuit force must not only move outward a considerable distance but must also move upward to an altitude at least as great, and preferably greater, than that of the approaching hostile aircraft. The movement outward may, therefore, consist of two components, the climb and level flight. The forward (horizontal) speed of an airplane is materially reduced during a climb. When climb is necessary, aircraft may proceed from the base to the possible L. I. at one rate of speed for a part of the distance and at another rate of speed for the remaining distance.

2) Thee distance which an airplane moves forward during a climb is a function of the time of climb and the rate of forward (horizontal) travel during the climb. Figure 4 shows the effect of differences in altitude on the forward distance traveled. The intercepting aircraft travel the distances c and c' at one speed and the distances f and f' at another and greater speed. The higher the altitude to which the aircraft climb, and the greater the time required to climb to that altitude, the greater will be the distance c or c'.

b. When the friendly aircraft utilize the ground alert method, the items of take-off and climb may be of considerable importance. The use of the air alert method serves to eliminate this delay and allows the friendly aircraft to reach the desired L. I. more quickly than can ground alert aircraft. When utilizing the air alert method, computations of time and space factors consider only the climb required to reach the desired altitude from the altitude at which the friendly aircraft are already flying.

55. ENEMY MOVEMENT.-a. If the friendly aircraft are to arrive at the desired L. I. at the same time the enemy aircraft arrive there, the enemy aircraft must be at a distance outward from the desired L. 1. which they can traverse in the time required for the friendly aircraft to move from the base to the desired L. I. It is essential, however, that the enemy aircraft be discovered and reported prior to their arrival at this point, to allow time for the transmission of the reporting message from the observer to the defending pursuit and for the necessary action to be taken prior to the starting of the movement from the base toward the desired L I.

b. ordinarily, It may be expected that messages reporting the presence and location of enemy aircraft will reach the information center a few minutes after the airplane has been observed. After the report reaches the information center time is required for initial instructions to be issued to the aviation force before it can proceed to the proper point on the desired L. I. When the ground alert system is being used, additional time must be allowed for the starting of engines and the take-off of the unit.

c. Figure 5 is a schematic representation of the relative positions of the friendly and enemy aircraft at various stages

of the operation, from discovery of the enemy aircraft to interception at the desired L. I.

SECTION VI -  TECHNIQUE OF INTERCEPTION

56. GENERAL.-Effective interception is dependent upon careful planning, rapid performance of all necessary functions, and accurate execution. The details of issuing orders, transmitting information, navigation, plotting, searching, and performing other essential functions will vary with different situations. In all situations, however, the critical factors are speed and accuracy. The time available in which to reach the desired line of interception is ordinarily very short, and all operations must be performed with the utmost rapidity but with accuracy.

57. CONTROL-a. Information and instructions are transmilled from the ground to aircraft in flight almost entirely by radiotelephony. A simple code system will serve to maintain secrecy and to decrease the length of messages. Routine messages, air-ground, or messages which are common should be listed and coded.

b. A grid system or a system of radial lines and concentric circles superimposed on a map of the area is a useful basis upon which to evolve the code for the transmission of navigation instructions and information of the enemy.

58. NAVIGATION.-a. Either pilotage or dead reckoning is employed to navigate the force to the interception. Pilotage is ordinarily used for short distances; when operations are being conducted over an area with which the personnel are familiar; or over an area containing landmarks which can be identified readily. Over water areas, unfamiliar terrain, or terrain on which landmarks are few, and under conditions where contact flying is impracticable, dead reckoning navigation may be necessary. Dead reckoning navigation may be performed by personnel in the aircraft or by personnel on the ground.

b. Navigation of pursuit units by ground control necessitates a procedure differing from that followed when navigation is directed in the air, as drift and actual speed cannot be determined by direct reading. Dead reckoning navigation from the ground must be based upon the wind data available and upon the known performance of the aircraft. The data required include

(1) Wind direction and speed at all operating altitudes throughout the area over which operations may take place.

(2) Rate of climb used to all altitudes.

(3) Airspeed (horizontal) of the aircraft during the climb.

(4) Airspeed of the aircraft in level flight at all altitudes.

(5) Weather conditions throughout the area over which operations may take place.

c. The navigation can be done on the ground only when the aircraft movements conform to a known standard. Knowing this standard, personnel on the ground are prepared to determine with considerable accuracy the direction in which the aircraft should fly, and the time which they should fly in that direction to make good a desired distance. The ground control is able by this means to determine the location of the friendly aircraft at any instant, and to direct the movement of those aircraft rapidly and accurately to the proper place at the proper time to effect interception. The accuracy of navigation is increased by position reports from the pursuit leader and from the aircraft warning service.

59. PLOTTING.-a. The information center receives information of the movements of enemy aircraft and relays this information to the unit in the air either in the form of navigation instructions or in the form of information of the enerny. The information center is equipped to receive and evaluate information of the enemy, to make decisions as to the action to be taken, and to transmit information and instructions to the flying echelon. In order to accomplish these functions, it is necessary that the movements of the enemy be plotted and future positions estimated. When navigation problems are being solved on the ground, It is also necessary to plot the position of the friendly aircraft and to forecast their future positions, as the solution of any interception problem involves a knowledge of the relative positions and speeds of the two forces.

b. (1) A satisfactory technique for plotting the movements of enemy aircraft, for plotting the movements of friendly aircraft, and for solving the interception problem has been evolved by the utilization of one large scale map of the area and a crew of four who work on the map. This crew is made up of the data keeper, target plotter, pursuit plotter, and intercept officer.

(2) The data keeper is charged with maintaining the latest available information on wind velocities, wind directions, weather conditions, and the performance of enemy aircraft. He is also responsible for the determination of the effect of wind on the movement of friendly aircraft.

(3) The target plotter is charged with the plotting of enemy movements and forecasting future enemy positions.

(4) The pursuit plotter is charged with the plotting of movements of the friendly aircraft and forecasting their future positions.

(5) The intercept officer is charged with the solution of the navigation features of the interception problem, and with directing the pursuit unit to a point in the air where interception with the enemy is assured.

c. When navigation is directed from the ground, an intercept officer of the unit usually directs the movements of the flying echelon. The flying echelon is retained under the tactical control of the commander on the ground until the enemy is sighted, at which time control passes to the formation commander. After the fight, the commander of the formation reports back to the commander on the ground, and again comes under the tactical control of the latter. When navigation is performed in the air, tactical control is vested in the formation commander throughout the entire operation.

NOTE.-Equipment has been developed for solving the interception problem by mechanical means that reduces the time involved in solutions and the number of operating personnel required at the control board. This reduction in time is of particular value when the hostile aircraft approach the defended objective on irregular courses. Under these conditions the saving in time should add to the probability of interception and reduce the time required. This will enable the defending pursuit to engage the enemy at a greater distance from the defended objective.

60. SEARCH~a. The technique of interception involves some search for the enemy regardless of the accuracy of the navigation. When contact with the enemy is imminent, the formation commander disposes his force for search. This disposition normally involves the detaching of special components to take position below, in front, and on the flanks of the main body. The main body spreads out to intervals determined by the space to be searched, the size of the force, the nature of the enemy force, and time required to assemble for the attack.

b. It is especially important that detachments always be sent to an altitude at or below the reported altitude of the enemy aircraft, unless the latter are flying at minimum altitude. Aircraft are more easily located against the background of the sky than against average terrain, and the searching personnel have but one hemisphere to scan.

SECTION VII - SUPPORT OF AIR STRIKING FORCES

61. GENERAL.-Support of air striking forces may be necessary when those operations are seriously threatened by hostile aviation forces. This support or security is accomplished by general or special support to those forces in flight and by protection of their ground bases.

62. METHODS OF SUPPORT.-a. General support.-Pursuit forces provide general support by gaining temporary or permanent air superiority throughout the area or sector of air attack operations. Any friendly pursuit forces operating in an area or sector provide a degree of general support to friendly aircraft operating in that area. When hostile fighter operations are so extensive that security provided by pursuit forces operating in general support is not effective, special support forces should be employed.

b. Special support.-Pursuit provides special support by escorting the supported formation through part or all of its mission, furnishing a screen against surprise and augmenting the defensive fire power of the supported force. Multiseater fighter aircraft having strong defensive fire power are normally assigned for these missions. When this type aircraft is not available, single-seater pursuit may be employed.

(1) Multiseater fighter aircraft having all-around defensive fire power take position relatively close to the supported force from which any hostile attack on the supported force may he met with maximum fire. Effectiveness of this support is dependent on the ability of the escorting force to concentrate fire in all vulnerable sectors.

(2) Single-seater pursuit forces furnish special support to friendly air attack formations by fire power controlled through maneuver. They normally operate above and to the rear of the defended formation from positions that guard vulnerable sectors and that facilitate immediate counterattack against any enemy force endeavoring to launch a direct attack on the defended formation. Distance from the supported force will be influenced by relative speeds, escort strength, and visibility conditions. Forces in special support counter attack immediately when hostile fighters make direct attacks on the defended formation. When possible, withdrawal from combat will be made when threat against the defended formation has been removed.

c. Protection of air striking force bases.-Support of the air force on the ground is accomplished by the same methods discussed in sections III and IV.

SECTION VIII - SUPPORT OF GROUND FORCES

63. GENERAL.--Operations of pursuit aviation in support of ground forces are based upon the needs of the ground forces and their supporting aviation. The pursuit  commander should be thoroughly familiar with the plan of operation of  the ground forces, the terrain over which they are operating, and the strength, disposition, and method of employment of enemy antiaircraft artillery so far as they may affect the success of supporting operations.

64. Missions.-Pursuit forces operating in direct support of ground forces may be employed in the execution of all of the following missions:

a. Antiaircraft security.

b. Protection of air support forces and organic aviation.

c. Counterreconnaissance.

d. Air attacks on ground troops and light materiel.

65. METHODS OF OPERATION.-Except for the attack of ground targets, pursuit executes its missions in direct support of ground forces by methods similar in character to operations previously treated in this manual. The specific application of these methods of operation is covered below.

a. (1) Pursuit provides antiaircraft security by operating in local or general defense. It operates by ground alert, air alert, or fighting patrol methods.

(2) When ground forces are in contact, antiaircraft security may best be obtained by offensive action, to gain temporary or permanent air superiority. This is accomplished by pursuit concentrations and/or offensively fighting patrols.

b. Pursuit aviation provides protection for air support forces by general or special support and by protection of their air bases as treated in section VII.

c. Pursuit aviation executes missions of counterreconnaissance by offensive or defensive fighting patrols. Counterreconnaissance is normally accomplished incident to other pursuit operations. Where enemy reconnaissance is extensive, special operations by fighting patrols may be necessary.

d. (1) Pursuit executes attacks on ground personnel and light materiel targets by employing light bombs and automatic weapons.

(2) So long as enemy air operations constitute a serious threat to successful ground operations, supporting pursuit forces will normally be employed against those forces and not diverted to attacks on ground objectives. However, in critical situations or when enemy air operations are relatively ineffective, pursuit aircraft can be employed effectively against ground personnel and light materiel, especially hostile antitank dispositions confronting friendly armored or mechanized forces.

66. FIGHTING PATROLS.-Operations should be conducted to provide a screen of offensive patrols so disposed as to deny the enemy air reconnaissance and observation and to assure interception of hostile aircraft before they can interfere with friendly air operations or attack ground objectives.

a. For these patrols to reap the full advantages of the initiative in air flghting and also be able to make the utmost use of surprise, they should be given as much freedom of action as is compatible with coordination of their operations with those of other patrols operating in adjacent areas.

b. It is inadvisable to restrict patrols more than is absolutely necessary in regard to the locality and altitude of operation. Orders should normally be confined to the definition of the task, leaving the patrol leader full latitude, within limits essential for coordination, in the execution of his task. The size of fighting patrols will be influenced by the methods employed by hostile aviation forces.

c. Owing to the ease of evasion in the air, it may often be necessary to augment these offensive patrols by establishing two or more lines at different altitudes. Even when large numbers of fighter aircraft are so employed, it may not be possible to prevent small enemy formations and single aircraft eluding the patrols or large formations forcing their way through them.

67. CONCENTRATIONS.--Certain critical operations of the ground forces may require local air superiority over a limited area for a definite period of time. Within the capacity of the pursuit force, such superiority is achieved through concentration of operations over the designated area for the period required. The need for such special support should be anticipated and proper provision made in preceding pursuit operations to insure the availability for the operation of the force required. Where the pursuit force is limited this will usually require that an appropriate force be conserved to accomplish this particular task.

SECTION IX - PURSUIT IN NIGHT OPERATIONS

68. GENERAL.-Pursuit operations at night will be limited by the availability of antiaircraft searchlights, suitable aircraft, and an effective aircraft warning service. There are two methods of making night interception:

a. By the combined use of pursuit and active searchlights.

b. By the joint use of air-borne and ground radio location devices.

69. NIGHT USE of AIRCRAFT WARNING SERVICE.-The aircraft warning service must function at night where pursuit conducts night operations.

70. SEARCHLIGHT COOPERATION.-The target must be illuminated for pursuit aviation to locate the enemy arid to attack. Searchlight illumination should be provided for pursuit operations beyond the operating range of antiaircraft guns and should provide for continuity of illumination for a sufficient time to permit pursuit to launch an assault.

71. NIGHT PURSUIT TACTICS.-a. Formations.-Pursuit will normally use reference lights except for those airplanes that are actually detached for the attack. The number detached will depend on the width of the bombardment formation as well as its depth. In general, it will not detach more than three at one time. The two-plane element is the normal unit for attacking at night. The three-plane element may be used when the hostile formation has sufficient width to justify the force.

b. Alerting pursuit.-Pursuit operating at night will be alerted on reports from the aircraft warning service. The force employed will be dispatched to an air alert station sufficiently distant from sound locators to insure noninterference. This air alert station should be along the most probable line of enemy approach.

c. Pursuit's position after location of enemy.-When radio or prearranged searchlight signals indicate the location of the hostile aircraft, the pursuit formation will proceed immediately to the indicated location. It will take its position outside of effective fire range from the bombardment formation and detach elements to attack.

d. The assault.-(1) The detached airplanes will extinguish their lights and maneuver quickly to effective range in rear of the hostile target and deliver the assault. Pursuit airplanes engaged in the assault will deliver their fire in long bursts. When the attack is completed, individual airplanes proceed directly to their airdrome and land.

(2) In the attack by two-plane elements the leader will be indoctrinated to attack always the right rear of the hostile formation, and the remaining pursuit pilot will concentrate simultaneously on the left rear of the formation. With three airplanes the leader will be indoctrinated to attack the rear center and the number two wingman the right rear, the number three, the left rear. Attacks are made simultaneously. The delivery of fire in one or two long bursts will insure that the attacking pursuit will finish at nearly the same time. In the event that several hostile formations or individual airplanes arrive at approximately the same time, the pursuit leader will detach the necessary units to attack according to his formation's strength. These detached elements will form small individual formations and proceed with the maneuvering and assault as described for the maneuver and assault of the parent formation.

e. Pursuit in artillery zone.-In night operations, which are coordinated with antiaircraft artillery, the pursuit personnel should know the limits of the zone of effective artillery fire. Normally the policy of the antiaircraft gun units will be to fire on unidentified airplanes within range. The interceptor commander of an area in which there are both pursuit aviation and antiaircraft artillery will prescribe instructions for the tactical coordination of pursuit and antiaircraft artillery fire.