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CHAPTER 7

ENGAGEMENT TECHNIQUES

Attack helicopters can be extremely effective if aircrews understand the techniques and standards associated with the employment of their weapons systems. This chapter discusses the terminology, procedures, and standards for helicopter fired weapons.

Section I. Modes and Types of Fire

7-1. TYPES OF FIRE

The two types of fire are direct and indirect. FM 101-5-1 defines direct and indirect fire as follows:

    a. Direct fire is "fire directed at a target that is visible to the aimer or firing unit."

    b. Indirect fire is "fire delivered on a target which cannot be seen by the firing unit."

7-2. MODES OF FIRE

Armed helicopters use three modes of fire--hover fire, running fire, and diving fire. Hover fire may be stationary or moving.

    a. Hover Fire. Hover fire is defined as any engagement conducted below ETL. For objectively scored gunnery ranges, hover fire is broken into two subgroups. When hover is specified on a gunnery task, the crew will conduct the task from a stationary hover. This definition is not intended to conflict with aircraft ATMs.

      (1) Stationary. Hover engagements occur with the aircraft at stationary hover. Both direct and indirect fires can be delivered during hover fire.

      (2) Moving fire. Moving fire is an engagement from a moving helicopter below effective translational lift. Horizontal movement may be in any direction, but some deliberate movement is present. Both direct and indirect fires can be delivered during moving fire.

    b. Running Fire. Running fire is an engagement from a moving helicopter above ETL. Both direct and indirect fires can be delivered during running fire. The forward airspeed adds stability to the helicopter and increases the delivery accuracy of weapon systems, particularly rockets.

    c. Diving Fire. Diving fire is a direct fire engagement from a helicopter that is in a diving flight profile according to the aircraft ATM. The airspeed and altitude of the aircraft improve the accuracy of engagements, particularly for rockets. The advantages of diving fire are as follows:

      Decreased vulnerability to small arms fire.

      Increased armament loads because of decreased power requirements.

      Increased accuracy due to less rotor downwash effects on munitions and a more stable launch platform.

      A smaller beaten zone in the target effect area.

7-3. TARGET EFFECT STANDARDS

The three target effect standards for armed helicopter engagements are suppression, neutralization, and destruction.

    a. Suppression. Popular definitions of suppression include--

      "Shoot enough to get their heads down."

      "Make those tanks button-up."

      "Shoot enough to cover my break."

      (1) However, FM 101-5-1 defines suppression as, "direct and indirect fires, electronic countermeasures, or smoke brought to bear on enemy personnel, weapons, or equipment to prevent effective fire on friendly forces."

      (2) Suppression for the individual aircraft is normally unplanned, is defensive in nature, and executed as a self-defense engagement. A suppression engagement is a hasty engagement to prevent, modify, or stop an enemy engagement. Aircrews should use suppression to break contact and gain maneuver time and space.

      (3) Suppression is not a decisive engagement. FM 101-5-1 defines a decisive engagement as, "an engagement in which a unit is considered fully committed and cannot maneuver or extricate itself. In the absence of outside assistance, the action must be fought to a conclusion and either won or lost with the forces at hand."

      (4) The crew firing the suppression engagement may not be able to observe target effect.

      (5) Aircrews may attempt suppression against virtually any target for self-defense. For example, a crew may have to engage an armored target with cannon at close range to gain time and situational awareness for egress.

      (6) Training suppression on live-fire gunnery ranges provides limited training value. The amount of ammunition required to suppress a target is not definable. In addition, all weapons mounted on armed helicopters have the capability to suppress targets.

    b. Neutralization. Neutralization knocks a target out of action temporarily. Neutralization of a target occurs when it suffers 10 percent or more casualties or damage.

      (1) Neutralization is the standard for rocket engagements. Neutralization is a deliberate engagement in which the crew fires a minimum of two pairs of adjustment rockets, senses the impacts, makes adjustments, and fires for effect with at least five pairs of rockets. This standard applies to both MPSM and PD rockets.

      (2) The crew selects a central aimpoint for multiple targets covering a large area and adjusts the aimpoint on observed impacts. Crews must observe the impacts of the sensing rockets to adjust for the fire for effect.

      (3) Rockets are most effective when fired in mass. For neutralization training, resource constraints do not allow aircrews to fire rockets in mass for fire for effect. The training strategy for neutralization is to teach and evaluate crews on their ability to select a central aimpoint (target center-of-mass) and adjust rockets onto the target without completing a decisive fire for effect.

      (4) The optimal solution for training and evaluating neutralization is for units to set-up an assembly area complete with tents and vehicles in the range impact area and allow the crews to engage the area with rockets. When a crew completes the engagement, the master gunner goes to the target area and counts impacts. While it would be interesting to watch, this level of targetry is totally impractical. Because of this, the neutralization standard for training is to use single (may be several) silhouettes on the range as central aimpoints. The crew adjusts the rockets onto the individual targets. The limits of the target effect area is defined by the AWSS.

      (5) All aircrews will train to the neutralization standard. Although commanders may consider suppression a more relevant rocket mission for his unit, neutralization will provide the maximum training value per trigger pull for basic and intermediate gunnery training.

      (6) Paragraph 7-5 contains more information on the employment of 2.75-inch rockets.

    c. Destruction. Destruction puts a target out of action permanently. Direct hits with high-explosive munitions are required to destroy hard materiel targets. Do not confuse destroying a tank with a destruction mission. Destruction often requires large expenditures of ammunition.

      (1) Destruction is a deliberate engagement.

      (2) Precision guided missiles are used against hard targets during destruction missions. While other weapons may be used for destruction, mission planning will normally focus on the standoff capability of TOW and Hellfire missiles.

Section II. Terminology and Information on Weapons

7-4. EFFECTIVE RANGE

FM 101-5-1 defines effective range as, "That range at which a weapon or weapons system has a 50 percent probability of hitting a target."

    a. A weapon's effective range extends from the minimum effective range to the maximum effective range. Maximum effective range is the longest range at which a weapon has a 50-percent probability of hitting a target.

    b. The standard target used in determining effective range for cannon are 3 x 3 meter plywood silhouettes. It is a "vehicle sized" target.

    c. The training tables contained in this manual require aircrews to engage targets within the effective range of the weapon with target-practice ammunition. However, crews may have to shoot long range engagements in combat using service ammunition.

7-5. 2.75-INCH ROCKETS

Whether fired from an AH-64, AH-1, or OH-58D (KW), the 2.75-inch rocket system displays similar characteristics. The intent of the following paragraphs is to provide general information applicable to all armed helicopters.

    a. The rocket system mounted on attack helicopters is a unique weapon system. Rockets fired from an attack helicopter possess characteristics of both direct and indirect fire weapons. Like indirect artillery fire, 2.75-inch rockets are most effective when fired in mass. In addition, helicopter crews can fire rockets in the direct fire and indirect fire mode.

    b. Crews can expect 7 to 12 mils of dispersion from rockets fired from helicopters. The MK 66 rocket motor spins clockwise up to 30 revolutions per second to motor burnout due to the flutes on the motor nozzle. As the motor burns out the rocket's clockwise rotation zeroes out and the wrap-around fins cause the rocket to begin a rapid counterclockwise rotation. Engineers designed this reversal of rotation for the following reasons:

      (1) The rocket's high rate of rotation may keep the warhead's set-back fuze from arming due to the centrifugal force of the spinning rocket.

      (2) The MPSM warhead's submunition ejection pattern is disrupted by high rates of rotation. The pattern of submunition impacts is inconsistent and provides poor target coverage without proper submunition ejection.

    c. Live-fire testing shows that rockets are most effective between 3,000 and 5,000 meters. These test results apply to both MPSM and unitary warhead rockets.

    d. Crews must select the proper weapon for the target to be engaged. The targets most suited for rockets are large target areas with high concentrations of enemy personnel and materiel. Figure 7-1 shows an example of a rocket target. The targets best suited for neutralization with rockets include--

      (1) Troops in the open.

      (2) Tactical assembly areas.

      (3) Command, control, and communications facilities.

      (4) Motor parks and vehicle marshalling area.

      (5) Convoys of thin-skinned vehicles.

      (6) River crossing sites.

      (7) Deployed artillery or air defense sites.

Figure 7-1. Example rocket range

7-6. BORESIGHTING AND DYNAMIC HARMONIZATION

    a. Armament personnel and aircrews must adjust each weapon system to ensure that the aiming point and impact point of the projectile are the same. Boresighting is the first step in this process. It involves adjusting the boreline axis of the weapon and the optical axis of the sight. Boresighting does not compensate for deviations caused by the ballistic characteristics discussed in Chapter 4.

    b. Normally, armament personnel are responsible for boresighting prior to range training. However, aircrews should be knowledgeable in the procedures for boresighting weapon systems. The publications in the references section describe boresighting procedures for specific helicopters and weapon subsystems. Table VI shows the ammunition for weapons calibration and verification.

    c. The dynamic harmonization procedure is for AH-64 units only. It is conducted during Table VI and greatly improves the accuracy of the 30mm cannon. This procedure in conjunction with the improved pylon and rocket launcher boresight procedure will greatly enhance the accuracy of the Apache's weapon systems. Unit crews must know the proper procedures for each task before attempting them.

    d. The range specified by the dynamic harmonization procedure, 1,000 meters, is selected to negate impact of environmental conditions. Additionally, the FOV diagrams and the correctors are scaled to that range.

NOTE: This procedure is not a replacement for the CBHK ground procedure.

Section III. Crew Techniques

7-7. FIRING TECHNIQUES

Firing helicopter weapons systems requires a great deal of skill by the pilot and CPG/CPO. These skills require development and sustainment. They include aircraft control and burst on target.

    a. Aircraft Control. Aircraft control is most critical when engaging targets with rockets. Rockets are affected by changes in pitch attitude and relative wind as they leave the launcher. Regardless of the engagement technique used, aircrews should use a consistent sequence. This sequence is known as the 4 Ts (target, torque, trim, target). The use of this sequence, regardless of your aircraft type, will assure a consistent launch. The following is a description of the sequence.

      (1) Target. Verify that the correct target is being engaged. Verify the correct azimuth. The pilot may select key terrain to assist in lining up on the target.

      (2) Torque. Verify that the torque required to maintain altitude and DO NOT CHANGE IT. Any torque changes during the firing sequence will affect the distance the rockets fly based on the changed induced flow from the rotor system.

      (3) Trim. The trim of the aircraft includes both horizontal and vertical trim. During hovering fire, the pitch attitude (vertical trim) should be verified for the range and adjusted with the cyclic. During running fire the trim of the aircraft (horizontal trim) should be verified and adjusted for with the pedals prior to firing. An out of trim condition will cause a deflection of the rockets on the opposite side the trim error occurs.

      (4) Target. Finally, reverify the correct target and azimuth prior to firing.

    b. Burst on Target. BOT is the technique used to adjust fires on target. This technique requires the crew member firing the weapon to sense the impacts of his engagement and use proper technique to adjust the rounds on target. BOT is used with cannon, machine gun, and rocket engagements. There are several techniques for applying BOT. They include--

      (1) Laser range finder method.

        (a) Select a narrow field of view on the helicopter's optics. Lase the target. Note the range to the target.

        (b) Fire a burst of cannon fire at the target.

        (c) Immediately select a wider field of view on the optics.

        (d) Note the impacts of the bullets.

          Lase the impact. Note the range to the impacts. The difference between the laser range to target and the laser range to the center of the bullet impacts is the range error.

          Note the azimuth to the impact. If impacts were right or left of target, make minor corrections in the aimpoint to the opposite side of the target to adjust bullets on the target.

        (e) Change the range.

          Add/subtract the range error to the original range to target and manually entering the corrected range into the aircraft.

          Add/subtract the range error from the original range to target and lasing either short or long of the target to get the corrected range.

        (f) Continue the engagement.

      (2) Mil relation method.

        (a) Select a narrow field of view on the helicopter's optics. Estimate the range to the target using mil values. Input or adjust the range manually, noting the range to the target.

        (b) Fire a burst of cannon fire at the target.

        (c) Immediately select a wider field of view on the optics.

        (d) Note the impacts of the bullets. Measure the distance between the impacts and the target using the symbology in the helicopter's optics. Using the mil values in Section III, Chapter 6, determine the distance (both in range and azimuth) from the target the impact occurred.

        (e) Change the range by adding or subtracting the range error to the original range to target and manually entering the corrected range.

        (f) Continue the engagement.

      (3) Recognition method. The recognition method is also known as "Kentucky Windage." This technique's effectiveness is directly proportional to the experience of the crew member making the corrections. To use this method, the crew member fires a burst, senses its impact, and estimates the amount of correction needed to adjust rounds on target. He adds or subtracts the adjustment from the original range and continues firing.

7-8. TTP FOR THE MODES OF FIRE

    a. Hover Fire. Hover fire is fire delivered when the helicopter is below effective translational lift, either in ground effect or out of ground effect. It may be stationary or moving, but movement during hover fire is always below ETL airspeed.

      (1) The "4 Ts" from paragraph 7-7 above apply to hover fire. Vertical and horizontal trim are important when engaging from a hover. Depending on the environmental conditions, many aircraft hover OGE very near their maximum torque available limit. The narrow power margin held by a loaded aircraft makes smooth, deliberate pilot inputs critical.

      (2) When firing at a hover, verify proper torque control by setting the collective and verifying that the vertical speed indicator is steady. Pitch of the aircraft should be confirmed with the attitude indicator or pilot symbology. Keep the aircraft stable for the most accurate shots. Drift with the wind if the threat situation and terrain permits.

      (3) AH-64 and AH-1F pilots can check the speed of the real wind around the aircraft. If a crew is shooting rockets on a windy day, a technique is to watch the true airspeed display and let it become stable, or "constant" prior to firing the rockets.

      (4) When firing from a hover, the attitude of the aircraft may prevent the pilot from seeing directly over the nose of the AH-1 and AH-64 aircraft. The pilot should select reference points identifiable from the aircraft to maintain aircraft alignment and position over the ground during the engagement.

    b. Running Fire.

      (1) The crew selects an initial point about 8 to 10 kilometers from the target. The IP should be an identifiable terrain feature. The IP is selected primarily as a function of the desired route to the target.

      (2) The aircraft departs the IP toward the target flying contour, using terrain to mask the approach.

      (3) Approximately 6 km from the target, the pilot starts a climb to achieve intervisibility with the target. Once the crew acquires the target, the pilot levels the aircraft.

      (4) At 5 km (rockets) or 1500 m (cannon) from the target, the pilot starts a shallow 3-to 5-degree dive angle and the crew begins engaging the target.

      (5) At 3 km (rockets) or 1 km (cannon) from the target, the pilot begins his break and uses terrain to cover his departure from the target area.

      (6) The crew returns for an immediate reattack on the target or returns to the IP and holds.

NOTE: The crew does not fly over the target in running fire.

    c. Diving Fire. Figure 7-2 shows diving fire. Use diving fire when--

      Line of sight to target from hover is obstructed and direct fire is required on target for destruction or neutralization mission.

      High volume of accurate rocket and cannon fire is required on the target and there is minimal air defense threat.

      High gross weight or environmental conditions prevent hover fire.

Figure 7-2. Diving fire

      (1) Both the AH-1 and AH-64 ATM address diving flight. TC 1-213 (Task 2069) and TC 1-214 (Task 2069) give specific performance standards for diving flight.

      (2) Techniques for firing weapons during diving flight are discussed below.

        (a) Use the 4 Ts in paragraph 7-7a (target, torque, trim, target). Proper aircraft control will greatly enhance the accuracy of the aircraft weapon systems, primarily with rockets.

        (b) Engage targets with rockets and cannon similar to techniques used in running fire. Use rockets employing point detonating fuses and used "fixed gun" for cannons during the engagement.

        (c) Use a careful cross-check because target fixation may cause the pilot to fly the aircraft into the ground. The pilot should complete the recovery from the dive no lower than 500 feet AGL for training.

        (d) Be aware that pitch cone coupling in the AH-1 and transient torque are more pronounced during diving fire and must be recognized by the pilot. Pilots must monitor rate of closure, rate of descent, and torque.

        (e) Understand that high rates of descent coupled with high flight path speeds require that the pilot closely monitor rate of closure and terrain features. The pilot must plan the dive recovery in time to avoid abrupt recovery maneuvers. If an abrupt recovery is attempted at high airspeed, "mushing" may occur. When the pilot tries to recover from a dive, the high rate of descent and high power setting cause the controls of the helicopter to become less responsive. Mushing may prevent the pilot from recovering the aircraft from the dive.

NOTE: The crew should avoid flying over the target in diving fire.

Section IV. Night Gunnery for Non-C-NITE AH-1

7-9. AH-1 NIGHT FIRING

    a. USAAVNC's position on AH-1 night gunnery is that only C-NITE equipped Cobras have a night gunnery qualification requirement. This was a Command Group decision made in 1989 based on the following facts concerning non C-NITE Cobras:

      Night vision goggles are not compatible with artificial illumination.

      AH-1 telescopic sight unit is not compatible with NVGs.

      Maximum range of the NVGs is approximately 800 meters, which restricts operational employment. This includes target acquisition and direct fire engagements.

      AH-1 units are not funded for illumination, neither internal with illumination rockets nor external with artillery or mortar illumination.

    b. The requirement to conduct AH-1 night gunnery should be based on the unit's METL. Considerations for firing the 20mm, 2.75-inch FFAR, and TOW missile while wearing NVGs are addressed in TC 1-204. Additionally, the new TC 1-213 requires aviators to perform gunnery tasks as part of NVG qualification and annual evaluation. The tasks, conditions, and standards outlined in the ATM gunnery tasks apply to NVGs as well. Night firing tactics, techniques, and procedures with illumination are similar to day-firing techniques.

    c. If an AH-1 equipped unit has the mission to fight at night, then the command that the unit belongs to has the responsibility to provide the resources and training for night fighting.

7-10. ISSUES WITH NIGHT AH-1 GUNNERY

    a. Because of the range limitations of the NVGs, indirect rockets are the only rocket engagements considered reliable with NVGs.

    b. NVGs mounted on the HSS helmet provide the AH-1F crew with the capability to place cannon fires on short range targets. When the cannon is not in coincidence with the pilot's or gunner's HSS, firing voltage is inhibited to the cannon. However, a trigger pull will dump live 20mm rounds overboard. Great care should be exercised with this technique. Based on the limitations of the NVGs, this technique is most useful at ranges between 300 and 800 meters.

    c. Suppression is a viable mission for the AH-1 not using artificial illumination. For example, using cannon to break contact during a night movement.

    d. Non-C-NITE AH-1 units have ammunition allocated for night sustainment gunnery, not qualification.

Section V. Air Combat Weaponeering

The purpose of this section is to provide information on helicopter weapons and their employment against airborne targets. The objective of air combat weaponeering techniques is to increase the survivability of the aviation force.

NOTE: When discussing sighting systems for air-to-air firing, the pilot needs to understand that it is far more important to know where the bullet is in relation to the sight at different ranges than it is to know how far the bullet can go.

7-11. WEAPON SYSTEMS ENGAGEMENT RANGES

    a. 20mm Cannon, AH-1F.

      (1) When fired FIXED GUN using the HUD sighting system, the 20mm cannon is boresighted to cause the bullet to pass through the center of the sight reticle at 1,351 meters and has a TOF of 2.41 seconds.

      (2) Recommended range switch setting is SHORT (1,000 meters). Elevation mil corrections for air combat engagement from 500 to 1,500 meters is minimal. Therefore, Kentucky Windage adjustments are easier and faster than range switch adjustment.

      (3) When using the range switch to set range to target and the target is closer or farther away than the range set, use Table 7-1 to improve accuracy for elevation.

Table 7-1. Range switch setting 20mm cannon

SWITCH SET

RANGE TO TARGET

MILS

SHORT

500

-25.53

SHORT

1000

0.00

SHORT

1500

+16.78

SHORT

2000

+38.04

      (4) Since the speed of the bullet is greatly reduced beyond 1,500 meters, detonation of HEI and/or API rounds are not guaranteed. Therefore, engagements beyond 1,500 meters using these rounds are not recommended.

      (5) Variations in altitude have a much greater effect on bullet deceleration than does the shooter's true airspeed. Projectile speed decay is directly proportional to air density. If you are shooting at an altitude above 6,000 feet MSL, the speed of the bullet would not decay as fast, resulting in slightly less drop of the bullet compared to a bullet shot at sea level.

      (6) By the time a 20mm projectile is 500 feet in front of the muzzle, it has effectively stabilized from all pitch and yaw moments.

    b. 30mm Cannon, AH-64.

      (1) The 30mm cannon when fired FIXED GUN has a bullet impact at 1,575 meters and a TOF of 3.9 seconds.

      (2) Recommended range setting is 1,000 meters. Elevation mil corrections for air combat engagement from 500 to 1,500 meters is minimal. Therefore, Kentucky Windage adjustments are easier and faster than readjustment for range. Use the information below to adjust your aim for elevation.

Table 7-2. Range adjustment for 30mm cannon

RANGE

AIM ADJUSTMENT

500

-29.0

1000

0.0

1500

+23.3

    c. TOW Missile System, AH-1.

      (1) Due to tracking limitations of the TOW missile system (35 mils per second), the minimum standoff range required to allow the missile to track its target increases as the speed of the target increases. Table 7-3 shows the minimum and maximum ranges required to engage a target at varying speed with an aspect of 90 degrees.

Table 7-3. Minimum and maximum ranges for TOW engagement

TARGET SPEED (KNOTS)

MIN RANGE IN METERS

MAX RANGE IN METERS

34

500

3750

68

1000

3750

102

1500

3750

136

2000

3750

170

2500

3750

204

3000

3750

238

3500

3750

255

3750

3750

      (2) When using the TOW missile to engage an aerial target, the amount of distance the target will travel during the missile's time of flight becomes very important. Table 7-4 shows the relationship between the target speed, range to target, and distance the target travels.

Table 7-4. Aerial target, TOW engagement

TARGET
SPEED (KNOTS)

RANGE TO TARGET

DISTANCE TARGET TRAVELED
(IN METERS)

34

500

3750

35

359

68

1000

3750

137

718

136

2000

3750

602

1435

204

3000

3750

1554

2153

255

3750

3750

2691

2691

    d. 2.75-Inch Rockets.

      (1) The MK 66 rocket motor reaches its maximum velocity within 400 meters after launch. For the purpose of air combat, the rocket warhead of choice is the flechette, followed by the MPSM and HE-PD.

      (2) The flechette warhead detonates 150 meters before the predetermined range set by the rocket management system. After detonation of the warhead, the flechettes are deployed at a 12-degree angle and create a flechette cloud that becomes a cylinder after 150 meters. The size of this cylinder is 15.7 meters (49.7 feet) in diameter.

      (3) Analysis of the firing characteristics of the flechette warhead indicates that firing three pairs of rockets at a range of 2,000 to 2,500 meters will result in a 75 to 82 percent probability of hit.

      (4) Table 7-5 shows range, TOF and velocity for the flechette and MPSM MK66 rockets for air combat engagements.

Table 7-5. Air combat engagement with rockets

RANGE
(METERS)

TIME OF FLIGHT
(SECONDS)

VELOCITY
(METERS PER SECOND)

1000

1.96

510

2000

4.38

413

3000

7.41

330

4000

11.0

278

5000

15.17

240

6000

19.93

210

7000

25.06

195

    e. Hellfire Missile. The maximum effective range of the Hellfire missile is over 8,000 meters. With an onboard laser designator, aircrews can engage targets at ranges up to the maximum effective range. Ideally, aircrews should engage enemy helicopters indirectly with the Hellfire. The target can be designated by OH-58D or ground lasers. This designation capability enables aircrews to fire the missile from concealed positions behind masking terrain.

    f. Stinger Missile. The Air-to-Air Stinger should be used at or near maximum range before the enemy can detect the friendly aircraft. In extended range firing where the friendly aircraft has not been detected, the aircrew should be aware that the ATAS has a detectable smoke signature under certain atmospheric conditions. The ATAS may be used in short-range firings of less than 1,000 meters. However, the minimum arming range may affect its lethality.

7-12. TARGET ENGAGEMENT FACTORS

    a. Range. Inaccurate range estimation results in rounds missing the target and reduces the element of surprise by alerting the enemy to an impending attack. Therefore, aircrews must train to estimate the range accurately. The following methods are recommended:

      Visual range estimation.

      Tracer burnout.

      Maps and photomaps.

      Electronic devices.

      Sight mil values.

Laser range finders are the most accurate of all of these methods.

    b. Target Motion. If a target is not stationary, it becomes necessary to aim the gun ahead of the target to compensate for motion. The lead requirements for a target's motion occurs because the target has a velocity and sometimes an acceleration.

      (1) The lead component compensating for the target's velocity is generally 85 to 90 percent of the total lead requirement and is a function of the target's true airspeed and aspect. The lead component compensation for target acceleration comprises the remaining 10 to 15 percent of the total lead requirement.

      (2) The lead for target velocity is a function of the target's TAS and aspect. The velocity of the target is not nearly as important as the LOS motion rate that it creates. The magnitude of that LOS rate is a function of the magnitude of the target rate of motion and distance. At longer ranges, a smaller LOS rate is required to match the target's rate of movement. As the range decreases, LOS rate will proportionally increase. To determine the amount of lead required to compensate for target velocity--

        Determine the amount of target movement in degrees per second, then multiply that number by 17.45. This number will give you the rate of target movement in mils per second.

        Multiply this number by the TOF of the bullet to the target. The result is the amount of velocity lead required. For example, if your aircraft is turning at 10 degrees/second (10 degrees x 1,745 = 174.5 mils/sec) to match (track) the target's velocity normal to the LOS, and the apparent TOF of the bullet is 0.5 seconds, the required velocity lead would be:

    Velocity lead = (174.5 mils/sec) x (0.5 sec) = 87.25 mils

    c. Target Acceleration (compensation for target acceleration during tail chase engagement). The targets acceleration does not actually increase the target's LOS before firing the bullet. What is required, however, is an additional lead component to compensate for the change in the target's motion path during the TOF of the bullet. The additional lead component compensates for a turning situation where the target is turning after the bullet is fired. A miss distance has been generated due to the target turning after the bullet left the gun. The magnitude of acceleration is a function of the total "Gs" (crew station "G" force) that the target aircraft is generating. Gun control theory assumes that over the short TOF of the bullet, the target's speed remains constant. The amount of correction will depend on the amount of "Gs" pulled by the target aircraft and TOF of the bullet. (This amount would not be greater that 50 mils in most cases.)

    d. Lead Angle.

      (1) Shooting at a moving target is easy. Placing a killing burst on it requires a great deal of skill. One of the biggest problems to solve is how much to lead the target. Without a fire control computer that is capable of computing lead angles, the pilot and gunner have an increased workload.

      (2) "Lead the speed" refers to leading the target aircraft by the number of mils equal to the aircraft's maximum speed. For example if an aircraft's maximum speed is 120 knots, lead the aircraft by 120 mils in an engagement. The following are a few rules of thumb for tracking airborne targets and engaging them. This technique will get the bullets going in the right direction, but will probably require adjustment by the pilot or gunner.

        (a) 7.62mm: Lead the speed.

        (b) 20mm Cannon: Lead the speed minus 20 percent.

        (c) 30mm Cannon: Lead the speed.

        (d) Rockets: Lead the speed plus 10 percent.

        (e) TOW/Hellfire: Track the target.

        (f) ATAS: Track the target.

    e. Weapons Guide. Table 7-7 shows the recommended weapon system to use for air combat at various ranges to target.

Table 7-7. Recommended weapon system for air combat

RANGE TO TARGET (METERS)

WEAPON SYSTEM

0 - 1250

7.62mm

0 - 1500

20mm or 30mm

700 - 2500

2.75" Rockets

2000 - 3750

TOW Missile

2000 - 8000

Hellfire Missile

1000 - 8000

Air-to-Air Stinger

    f. Sight Reference. Mil values for sights are contained in the Chapter 6.



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