CHAPTER 5

MUNITIONS FOR HELICOPTER WEAPON SYSTEMS

The training munitions discussed in this chapter should be available through the logistical system. Combat, or service munitions, may not be found in a particular theater of operations. The theater command or, in some cases, a specific geographical area may require different types of munitions and/or different packaging configurations. Some Department of Defense ammunition codes are listed with the munitions that are described. Additional identification codes may be necessary to distinguish the type of munitions, series, warhead and fuze combinations, grouping sequence, packaging, package quantity, and availability. Any munitions that cannot be positively identified will not be loaded onto an aircraft, into a weapon, or into the feed system. All munitions must be identified at the ammunition supply or transfer point prior to receipt and distribution to the unit.

Section I. Linked Ammunition

5-1. 7.62 MILLIMETER FOR M60/M60D/M240 MACHINE GUN

a. The 7.62 mm ammunition is percussion-primed; chamber pressure is 50,000 psi for both the ball and the tracer. Projectile weight varies from 142 grains (.32 ounce) for the tracer to 150 grains (.34 ounce) for the ball. Muzzle velocity averages 2,750 feet per second. Figure 5-1 shows all 7.62mm service and training ammunition described below.

(1) Ball (M80 or M59). The M80 or M59 ball is intended for use against personnel and unarmored targets.

(2) Tracer (M62). The M62 tracer permits observation of the projectile's trajectory to the point of tracer burnout or to the point of impact. It is also used for incendiary effect and signaling. Tracer burnout occurs at approximately 900-950 meters.

(3) Armor piercing (M61). The M61 armor piercing projectile is used against light armor, concrete shelters, and similar bullet resistant targets. It is not intended for use in a training environment.

(4) Frangible ball (M160). The M160 frangible ball can be used during initial training on the M60 machine gun. It can be fired on indoor ranges if the range is ventilated to prevent buildup of toxic "bullet dust".

(5) Blank (M82). The M82 blank is used for training exercises in weapons equipped with blank firing adapters.

(6) Dummy (M172). The M172 dummy is used for weapon loading practice and for testing the weapon mechanism.

Figure 5-1. 7.62mm munitions

b. DODACs for 7.62 mm. DODACs of linked ammunition for the M60 and M60D machine guns are shown below. TM 43-0001-27 lists only one type of metallic link (M13) for all 7.62mm linked ammunition.

• 1305-A143 M80 Ball, l00/linked belt.

• 1305-A146 M62 Tracer, 100/linked belt

• 1305-A131 M80 Ball and M62 tracer (4 to l mix), l00/ linked belt.

• 1305-A147 M160 Ball, frangible, l00/linked belt.

• 1305-A159 M172 Dummy, 100/linked belt.

• 1305-A111 M82 Blank, l00/linked belt.

5-2. .50 CALIBER FOR OH-58D(I) KIOWA WARRIOR

a. The .50 caliber ammunition is percussion primed; chamber pressure is 52,000 psi for the tracer and 59,000 psi for armor piercing ammunition. Projectile weight varies from 619 grains (1.36 ounces) for the AP to 662 grains (1.45 ounces) for the ball. Muzzle velocities vary from 2,700 feet per second for the M1 tracer to 3,400 feet per second for the M23 incendiary. Neither armor piercing nor incendiary ammunition is intended for use in a training environment. Table 5-1 shows the approximate time of flight and approximate ballistic drop with the M33 ball. Figure 5-2 shows .50 caliber service and training ammunition described below.

Range to Target (meters)	Time of Flight (seconds)	Ballistic Drop (mils)
1,000	1.5	9
1,500	2.7	18
2,000	4.3	33

Table 5-1. M33 projectile ballistic data (values are approximate)

(1) Ball (M2 and M33). The M2 ball and the M33 ball are intended for use against personnel and unarmored targets. Muzzle velocity of the M33 is approximately 2,910 feet per second; the M2 is 2,810 feet per second.

(2) Tracer (M1, M10, and M17). The M1, M10, and M17 tracers permit visible observation of the in-flight path or trajectory to the point of impact. The M1 is limited to training use in CONUS. The M10 exhibits a trace from approximately 100 meters from the muzzle to approximately 1,600 meters from the muzzle.

(3) Armor piercing (M2). M2 armor piercing ammunition is used against lightly armored or unarmored targets, concrete shelters, and similar bullet resistant targets.

(4) Incendiary (M1 and M23). Impact with a hardened or armored target will cause incendiary composition to burst into flame and ignite flammable material. The incendiary charge of M1 is 34 grains; the M23 is 90 grains.

(5) Armor piercing incendiary (M8). M8 armor piercing incendiary ammunition combines the function of the AP and incendiary bullet. The incendiary charge of the M8 is 15 grains.

(6) Armor piercing incendiary tracer (M20). The M20 combines the functions of the AP and the incendiary and adds a tracer element. The incendiary charge is 27 grains.

(7) Dummy (M2). The M2 dummy is used to practice loading and test the weapon's ammunition feed system and mechanical function.

(8) Blank (M1 and M1A1). The M1 and M1A1 blanks are used to simulate firing in training exercises. The M1A1 is used with the M2 machine gun and the M19 blank firing adapter.

(9) Target practice ball (M858) and plastic tracer (M860). The M858 ball and tracer are intended for scaled range training with the M2 machine gun. The maximum range of this ammunition is 700 meters. The tracer round provides trace from 20 to 150 meters. This target-practice ball and tracer round is constructed of molded, high-density polyethylene plastic.

Figure 5-2. .50-caliber munitions

b. DODACs for .50 caliber. DODACs for linked .50-caliber ammunition for the M2 machine gun are as follows (some may be discontinued and/or there may be a newer series of ammunition packaging applications):

• 1305-A555 M33 Ball, 100/linked belt.

• 1305-A572 M17 Tracer, 100/linked belt.

• 1305-A557 M33 Ball / M17 Tracer (4 to 1 mix), 100/linked belt.

• 1305-A576 M8 API / M20API-T (4 to l mix), l00/linked belt.

• 1305-A543 M20 AP-I-T, l00/linked belt.

• 1305-A598 M1A1 Blank, 100/linked belt.

• 1305-A602 M858 TP / M860 TP-T (4 to 1 mix), 100/linked belt.

NOTE: Only M2 and/or M9 closed loop links are used with the M2 machine gun.

5-3. 20 MILLIMETER FOR AH-1E/F

a. Twenty millimeter ammunition is electrically primed; chamber pressure varies from 60,500 to 61,500 psi. Projectile weight of the M56 HEI round is 1,543 grains (3.5 ounces); other 20mm projectiles are of comparable weight. Muzzle velocity for the types of 20mm ammunition discussed below averages 3,380 feet per second. Types of 20mm munitions available are discussed below and shown in Figure 5-3.

(1) Target practice M55A2. M55A2 TP ammunition is used for gunnery training and test firing in lieu of the service round. It has a hollow cavity projectile body without a fuze (inert). The nose of the round is constructed of aluminum and is swaged to the projectile body.

(2) Target practice tracer M220. Except for the addition of a tracer element, the M220 TPT is very similar physically and ballistically to the M55A2. Tracer burnout usually occurs at a range of approximately 1,500 meters (±100 meters).

(3) High explosive incendiary M56A3/A4. Functioning with both explosive and incendiary effect, the M56A3/A4 HEI is intended for use against ground targets, including lightly armored vehicles. This thin walled, steel projectile can produce casualties to exposed personnel within 2-meter radius. It has a base plate that prevents ignition of the incendiary mixture by propellant gases. The M56A3/A4 is assembled with a single action M505A3 point detonating fuze. The explosive charge is 165 grains (.37 ounce); the incendiary charge is 20 grains. The HE mix and the incendiary mix are combined into one pellet in the A3 HEI.

(4) Armor piercing incendiary M53. The M53 API is intended for use against lightly armored targets. It functions with a combined incendiary and has a penetrating effect. The body of the projectile is constructed of solid steel; the nose is constructed of an aluminum alloy. The incendiary charge is 65 grains (.14 ounce).

(5) High explosive incendiary with tracer and self-destruct feature (M246/M246A1). The M246/M246A1 HEI-T-SD is intended for use against aerial targets. It has an HEI charge, a self-destruct relay charge, and a tracer element. It is assembled with an M505A3 point detonating fuze. The tracer burns for about 5 seconds whereupon the relay charge ignites and detonates the HEI charge. If impact with the target occurs before self-destruction, the PD fuze causes the HEI charge to detonate. The M246 has the HE and incendiary mix combined as one pellet; the M246A1 has the HE and incendiary charge loaded as separate pellets.

(6) Dummy (M51A2/XM254). The M51A2 is an inert round of solid metal construction and is used for nonfiring system loading and system checkout. The XM254 is constructed of plastic. As with the M51A2, the M254 also reduces wear on gun components and feed mechanisms.

b. Twenty millimeter fuze functioning and penetration are affected by velocity and angle of impact at all ranges, particularly at ranges in the upper one third of the 2,000 meter value. However, this depends on the type of target that is engaged. Rounds with an R50 value, a 50-percent chance penetrating rolled homogeneous armor at the given condition and range, are as follows:

• M56 HEI: .25 inch (6.3 mm), RHA at 60 degrees, obliquity at 221 meters; .50 inch (12.5 mm), RHA at 0 degrees, obliquity at 104 meters.

• M53 API: .25 inch (6.3 mm), RHA at 0 degrees, obliquity at 1,000 meters.

• M940 MPT-SD: .25 inch (6.3 mm), RHA at 60 degrees, obliquity at 940 meters; .50 inch (12.5 mm), RHA at 0 degrees, obliquity at 518 meters.

For comparison, Table 5-2 shows the hull and turret thickness of some common armored vehicles.

Figure 5-3. 20mm munitions

Vehicle	Thickness of Hull		Thickness of Turret
BTR-70	.40 inches	10 mm	.28 inches	7 mm
BRDM 2	.56 inches	14 mm	.28 inches	7 mm
BMP	.76 inches	19 mm	.92 inches	23 mm
BMD	.60 inches	15 mm	1.0 inch	25 mm
ZSU 23-4	.37 inches	9 mm	.35 inches	9 mm

Table 5-2. Hull and turret thickness of selected vehicles

NOTE: Rechambering live ammunition is prohibited. The chambering action could loosen the projectile in the cartridge case and break the waterproof seal. A broken seal could contaminate the propellant and primer and cause a misfire or hangfire.

c. Table 5-3 shows the approximate time of flight and approximate ballistic drop with 20mm ammunition.

Range to Target (meters)	Time of Flight (seconds)	Ballistic drop (mils)
1,000	1.5	9
1,500	3	21
2,000	5	42

Table 5-3. Approximate time of flight/ballistic drop 20mm,

M56 HEI fired from hover.

d. DODACs FOR 20mm. DODACs for linked 20mm ammunition for the M197 cannon are as follows (some listed may be obsolete are no longer available):

• 1305-A896 M55A2/M220 TP/TP-T (4 to 1 mix), 100/linked belt.

• 1305-A652 M220 TP-T, 100/linked belt.

• 1305-A918 M53 API, 100/linked belt.

• 1305-A653 M56/M220 HEI/TP-T (4 to 1 mix), 100/ linked belt.

• 1305-A655 M56/M220 HEI/TP-T (7 to 1 mix), 100/ linked belt.

• 1305-A792 M246A1 HEI-T-SD, 100/linked belt.

• 1305-A919 M56A4 HEI, 100/linked belt.

• 1305-A781 M51A2 Dummy, 100/linked belt.

NOTE: The M197 cannon and feed system requires M14A2 linked 20mm ammunition.

5-4. 30 MILLIMETER FOR THE AH-64 M230 CANNON

The 30mm ammunition for the M230 cannon is electrically primed; chamber pressure has been measured at 40,600 to 44,950 psi. Muzzle velocity is 2,640 feet per second for both the TP and HEDP. Table 5-4 shows the approximate times of flight and approximate ballistic drop of the 30mm projectile. Types of 30mm munitions available are discussed below and shown in Figure 5-4.

a. Target Practice M788. The M788 TP is an inert projectile without a fuze and is used for gunnery training in lieu of service ammunition. Its three-piece assembly consists of a steel body with a cavity, a rotating band, and an aluminum nose. The cartridge case is aluminum. This round serves no other purpose than for target impact or penetration.

b. High Explosive, Dual Purpose M789. The M789 HEDP is an anti-materiel and anti-personnel round. The projectile body is steel and is loaded with a 340 grain (.76 ounce) explosive charge and a spin compensated shaped charge liner that has a PD (M759) fuze. The cartridge case is aluminum. The fuze arms while the projectile is in flight and initiates the projectile's explosive filler upon impact. The shaped charge liner collapses with detonation that creates an armor piercing jet. Fragmentation of the projectile body also occurs that can produce antipersonnel effects within a 4-meter radius. Estimated penetration performance was interpolated from a graph contained in a gun system effectiveness report. This report reflected penetration in excess of 2.0 inches (50 mm) RHA at 2,500 meters.

c. Dummy (M848). The M848 dummy is used for function checks of the weapon mechanism and to test the linking and delinking operations. It is an inert cartridge with an anodized aluminum case and a modified TP projectile. The primer and the propellant are replaced on the M848 with a threaded steel bolt to maintain the same weight as the TP round.

Range to Target (meters)	Time of Flight (seconds)	Ballistic drop (mils)
1,000	2	15
1,500	3.7	32
2,000	5.8	60
2,500	8.6	100
3,000	12.2	160

Table 5-4. Approximate time for flight and approximate ballistic drop

for 30mm ammunition (M789 fired from hover)

Figure 5-4. 30mm munitions

d. DODACs for 30mm. DODACs for linked 30mm ammunition for the M230 cannon are as follows:

• 1305-B120 M788 TP, 72 rounds linked.

• 1305-B118 M788 TP, 11 round carton pack.

• 1305-B130 M789 HEDP, 72 rounds linked.

• 1305-B129 M789 HEDP, 11 round carton pack.

• 1305-B134 M848 Dummy, 72 rounds linked.

• 1305-B133 M848 Dummy, 11 round carton pack.

Section II. Rockets

5-5. 2.75-INCH ROCKETS

a. Hydra 70 is the name associated with the family of 2.75-inch (70 millimeter) rockets. Hydra 70 refers to the Mark 66 rocket motor with any warhead/fuze combination. The MK 66 rocket motor was designed to provide a common 2.75-inch rocket for helicopters and high-performance aircraft.

The MK 66 Mod 1 can be inadvertently ignited by electromagnetic radiation, especially by radio frequencies found aboard Navy ships. Both the Mod 2 and Mod 3 have hazards of electromagnetic radiation to ordnance (HERO) filters, , and the Mod 2 filter may prevent the AH-1 rocket management system from inventorying. The Mod 1 and Mod 3 are the standard motor for Army use. The Mod 4 will be the standard motor for all services once it is fully fielded. Mod 4 motors will be similar in appearance to Mod 3 motors. Figure 5-5 shows MK66 rocket motors.

b. Table 5-5 shows rocket motor comparison data extracted from TM 430001-30.

c. M260 and M261 launchers are required to fire the MK 66 rocket. They have reduced system weight and provide remote set fuze interface capabilities. The M158A1 and M200 launchers are not compatible with the MK 66 rocket motor.

Figure 5-5. MK 66 rocket motors

CHARACTERISTIC	MK 66
Length without warhead	41.7 inches
Weight before firing	13.6 lbs.
Motor burn time (77F)	1.05 - 1 .1 sec.
Average thrust	1,300 -1370 lbs.
Average spin rate	9 - 10 rps
Motor burn out	1280 feet (397 m)
Velocity at motor burnout	2425 fps
Maximum range at QE 42 degrees (MPSM warhead ground launch)	8,700 meters

Table 5-5. Rocket motor data

5-6. ROCKET WARHEADS (TACTICAL AND TRAINING)

a. M151 High Explosive. The M151 HE is an antipersonnel, antimateriel warhead and is traditionally referred to as the "10 Pounder." The bursting radius is 10 meters; however, high velocity fragments can produce a lethality radius in excess of 50 meters. The nose section is constructed of malleable cast iron that is threaded to receive the fuze. The base section is constructed of steel or cast iron and is threaded so that it can be attached to the rocket motor. The base section and the nose section are welded (brazed) together. Total weight of the loaded, unfuzed, warhead is 8.7 pounds, of which 2.3 pounds is composition B4. The M151 can be used with M423, M429, and M433 fuzes. The body of the warhead is olive drab with a yellow band and yellow or black markings.

b. M274 Smoke Signature (Training). This training rocket provides a ballistic match for the M151 HE warhead. The casing is a modified WTU-1/B with vent holes or blowout plugs. A modified M423 fuze mechanism is integral to the warhead. A cylindrical cartridge assembly is in the forward section of the casing; it contains approximately 2 ounces of potassium perchlorate and aluminum powder that provides a "flash, bang, and smoke" signature. The M274 weighs 9.3 pounds. The body of the warhead is blue with a brown band and white markings.

c. M261 High-Explosive Multipurpose Submunition.

(1) The MPSM warhead provides improved lethality against light armor, wheeled vehicles, materiel, and personnel. It has a plastic nose cone assembly, an aluminum warhead case, an integral fuze, an expulsion charge, and nine M73 submunitions. The primary warhead fuze, M439, is remotely set with the ARCS, MFD, or RMS to provide range settings (time of flight) from 500 meters to approximately 7,000 meters. On the AH-1, the RMS is programmable only from 700 meters to 6,900 meters. The body of the warhead is olive drab with a yellow band and yellow markings.

(2) Initial forward motion of the rocket begins the fuze timing. The expulsion charge is initiated at a point before and above the target, approximately 150 meters, depending on the launch angle. The submunitions are separated by ejection, and arming occurs when the RAD (Ram Air Decelerator) deploys. The RAD virtually stops forward velocity and stabilizes the descent of the submunition. An M230 omnidirectional fuze with an M55 detonator is used on each submunition and is designed to function regardless of the impact angle.

(3) Each submunition has a steel body that has a 3.2-ounce shaped charge of composition B4 for armor penetration. The submunition is internally scored to optimize fragments against personnel and materiel. Upon detonation, the shaped charge penetrates in line with its axis and the submunition body explodes into high velocity fragments (approximately 195 at 10 grains each up to 5,000 feet per second) to defeat soft targets. The fuzed weight of the M261 is 13.6 pounds.

(a) Approximate target area coverage. Figure 5-6 shows the approximate target area coverage of one M261 warhead. At shorter ranges, the RAD takes longer to overcome momentum, increasing dispersion. As range increases, the rocket loses momentum, increasing the effectiveness of the RAD. This increased effectiveness reduces submunition drift and ground dispersion. Trees, rocks and other natural or man-made structures within the target area may cause the submunition to detonate or land in a dispersion pattern other than the one shown in Figure 5-6.

(b) Probability of impact angle. Aerodynamic forces affecting submunitions during vertical descent may prevent them from landing upright (0 degrees off center). Sixty-six percent of the time a submunition will land 5 degrees off center; thirty-three percent of the time a submunition will land 30 degrees off center.

(c) MPSM lethality potential. Each M73 HE submunition has a shaped charge that can penetrate in excess of 4 inches of armor. A submunition that lands 5 degrees off center has a 90-percent probability of producing casualties against prone, exposed personnel, within a 20-meter radius. A submunition landing 30 degrees off center has a 90-percent probability of producing casualties within a 5 meter radius.

Figure 5-6. Approximate target coverage of one M261 warhead

d. M267 MPSM Smoke Signature (Training). The M267 MPSM training warhead operationally, physically, and ballistically matches the M261. Three M75 practice submunitions and six inert submunition load simulators take the place of the nine HE submunitions in the M261 warhead. Each practice submunition contains approximately 1 ounce of pyrotechnic powder. An M231 fuze with an M55 detonator is used with practice submunitions. The body of the warhead is blue with a brown band and white markings.

e. M257 Illumination. The M257 illumination warhead provides one million candlepower for 100 seconds or more. It can illuminate an area in excess of 1 square kilometer at optimum height. A deployed main parachute descent is approximately 15 feet per second. An M442 integral fuze provides a standoff range of approximately 3,000 meters with the MK 40 motor and approximately 3,500 meters with the MK 66 motor. The weight of the M257 is 10.8 pounds, of which 5.4 pounds is magnesium sodium nitrate. The body of the warhead is olive drab with white markings.

f. M229 High-Explosive. The M229 HE warhead is currently in the inventory. It is an elongated version of the M151 and is commonly called the “17 Pounder”. The M229 filler consists of 4.8 pounds of composition B4 and has the same fuzes as the M151. Its unfuzed weight is 16.4 pounds. The body of the warhead is olive drab with yellow markings.

g. M156 White Phosphorous (Smoke). The M156 is primarily used for target marking and incendiary purposes. It ballistically matches the M151 and is of similar construction. Filler for the M156 is 2.2 pounds of WP with a .12-pound bursting charge of composition B. The approximate weight of the fuzed warhead is 9.7 pounds. The M156 uses M423 and M429 fuzes. The M156 is no longer in production but still may be found in the inventory. The body of the warhead is light green with a yellow band and red markings.

h. M264 Red Phosphorous (Smoke). The M264 smoke screen warhead contains 72 red phosphorous wedges that are air-burst ejected over the intended target area and immediately begin producing a nontoxic, high-density, rapid-spreading, yet persistent smoke screen. The smoke generated by the 72 red phosphorous wedges blocks the entire visual spectrum as well as much of the infrared spectrum. The smoke generated by 14 M264 rockets will obscure a 500 meter (1640 feet) front, in less than 60 seconds for a duration of 5 minutes, in support of ground forces. The warhead weighs 8.5 pounds, of which approximately 5.2 pounds are red phosphorous wedges. The warhead uses an M439 remote set electromechanical fuze. The body of the warhead is light green with a brown band and black markings.

i. M247 High-Explosive. The M247 is no longer in production; however, some of these warheads may still be found in war reserve stocks. With a shape charge for an antiarmor capability, the M247 employs a cone shaped charge like that of the M72 LAW. The point initiated detonating fuze (M438) is an integral part of the warhead. The weight of the M247 is 8.8 pounds, of which 2.0 pounds is composition B. The body of the warhead is black with yellow markings.

j. M255A1 Flechette. The M255A1 flechette warhead contains 1,179 60-grain hardened steel flechettes. It is designed for use with the M439 fuze and has possible air-to-air as well as air-to-ground application. Figure 5-7 shows all current production warheads. The body of the warhead is olive drab with a band of white diamonds and white markings.

k. M278 IR Illumination . This warhead was designed for battlefield target illumination in conjunction with night vision goggles (NVG). The flare warhead is assembled to the MK66 Rocket Motor in the field. The flare and rocket can be launched from either fixed-wing or rotary-wing aircraft. The M278 provides an average near IR light output of 222 watts/steradian and less than 1K candle power of visible light. The IR flare will provide IR light for 3 minutes. Time to candle ignition from launch is 13.5 seconds. The body of the warhead is black with white markings.

M261 High-Explosive Submunition

M267 Smoke Signature Submunition

M257 Illumination / M278 IR Flare*

M151 High-Explosive

M255A1 Flechette

M274 Smoke Signature (Training)

M229 High-Explosive

M264 Red Phosphorous (Smoke)

* The M257 Illumination and the M278 IR flare warheads utilize similar housings.

Figure 5-7. 70mm warheads in production

5-7. FUZES

a. M423 Point Detonating. The M423 PD is an oblique sensitive, point-detonating, superquick fuze used as a common component with the M151. The safety and arming device forward of the booster housing (explosive charge) contains an unbalanced rotor. Upon acceleration of the rocket at firing, a weight setback occurs in the unbalanced rotor assembly which houses the primer and detonator. This setback places the fuze into an armed condition when the rocket has traveled approximately 52 to 110 meters from the launcher.

b. M429 Proximity. Currently in inventory, the M429 proximity fuze is a transistorized, continuous wave, doppler device that provides air burst functioning for improved antipersonnel effectiveness. The arming mechanism of the M429 is similar to the one in the M423 except that it has been modified to include a battery and an electric detonator. Once it is armed and the reflected signals reach a specific intensity, the firing circuit is initiated through a capacitor to the electric detonator that provides the air burst function. A superquick impact switch serves as a backup to the air burst electronics.

(WARNING: Multiple firing of rockets with this fuze is not permitted [no pairs, no salvos, or ripple fire]. Fire in single rocket mode only. Radio frequency interference between fuzes can cause premature functioning.)

c. M433 Resistance Capacitance. The M433 RC is a nose mounted, multioption, time delay fuze with selectable functioning modes. A superquick setting is used for open terrain; a forest penetration mode permits a selectable time delay range (10 to 45 meters in 5-meter increments) set for the height of the forest canopy. After first contact with the forest canopy, a delay timer is activated to provide warhead functioning. The bunker or building penetration mode provides up to 10 feet of penetration before detonation. The target penetration RC timer is activated by a point mounted probe switch that is initiated by target contact. An umbilical assembly is positioned on the nose of the fuze for interface through the launcher and RMS or ARCS and the aircraft. When the trigger is pulled, aircraft voltage is supplied to the fuze and the time delay is initiated as selected by the pilot.

d. M439 Resistance Capacitance. The M439 RC is a base mounted, electronic variable, time delay fuze with an RC delay circuit. Designed for cargo and flechette warheads, the M439 allows the pilot to remotely set the fuze for air burst functioning at the desired range from 500 to 7,200 meters. A fuze capacitor is charged by the RMS, ARCS, or MFD through an umbilical assembly. The fuze has no internal battery, and the required voltage is supplied by the aircraft through the remote set fuze subsystem. When the rocket is fired and normal acceleration occurs, the fuze is armed and timing starts. If the fuze is set but the rocket motor fails to fire, the rocket should not be loaded into another tube and fired. When the fuze is set a second time, the function time will increase for shorter ranges and decrease for longer ranges. It should not be used for accurate measurement until 10 days has elapsed before resetting it. The detonator is initiated electrically, depending on the range setting (time of flight), and ignites the expelling charge. Figure 5-8 shows production fuzes.

e. M422/M446 Fuzes. The M442 and M446 fuzes are base mounted, air burst, motor burnout delayed fuzes. They are integral fuzes used with the M257/M278 illumination and M259 WP smoke rockets, respectively.

Figure 5-8. 70mm fuzes in production.

f. DODICs for Rockets. DODICs listed in Table 5-6 are for rockets (complete round with MK 66 motors) which are currently in the inventory. The DODICs listed in Table 5-7 include all warhead/motor combinations which are now available or which will be available in the near future. Also, note that the users are indicated.

Table 5-6 DODIC/NSN cross reference for selected HYDRA-70 2.75 inch rocket items which are found in current stocks.

COMPLETE ROUNDS DODIC		NSN		CONFIGURATION		PACK
	H154		1340-01-371-8611		M278/M442/MK66-2		3
	H165		1340-01-269-1447		M261/M439/MK66-3		4
	H181		1340-01-249-7721		M257/M442/MK66-1		3
	H182		1340-01-249-7720		M257/M442/MK66-2		3
	H183		1340-01-268-7175		M257/M442/MK66-3		3
	H184		1340-01-289-4719		M264/M439/MK66-3		4
	H462		1340-01-309-5799		M255/M439/MK66-3		4
	H463		1340-01-108-8849		M267/M439/MK66-1		4
	H464		1340-01-108-8850		M261/M439/MK66-1		4
	H582		1340-01-269-9122		M151/M433/MK66-3		4
	H583		1340-01-269-9123		M151/M423/MK66-3		4
	H642		1340-01-309-8300		M229/M423/MK66-2		4
	H973		1340-01-238-2068		M274/ N/A /MK66-2		4
	H972		1340-01-238-2067		M274/ N/A /MK66-1		4
	H974		1340-01-268-7174		M267/M439/MK66-3		4
	H975		1340-01-269-1446		M274/ N/A /MK66-3		4
	H163		1340-01-108-8851		M151/M423/MK66-1		4
	H164		1340-01-110-2672		M151/M433/MK66-1		4

Table 5-6 DODIC/NSN cross reference for selected HYDRA-70 2.75 inch rocket items which are found in current stocks.

Table 5-7 DODIC/NSN cross reference for all HYDRA-70 2.75 inch rocket items which are in the inventory presently or which will soon be fielded.

Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
H583	1340-01-379-6277	M151 HE/M423 PD	Mod 3	Fastpack	48	Army	48 per pallet
HA12	1340-01-446-7680	M151 HE/M423 PD	Mod 4	Fastpack	48	Army	48 per pallet
H583	1340-01-269-9123	M151 HE/M423 PD	Mod 3	Wood	4	Army	60 per pallet
HA12	1340-01-448-8889	M151 HE/M423 PD	Mod 4	Wood	4	Army	60 per pallet
H975	1340-01-379-7118	M274 Smoke Sig Prac	Mod 3	Fastpack	48	Army	48 per pallet
HA13	1340-01-446-4094	M274 Smoke Sig Prac	Mod 4	Fastpack	48	Army	48 per pallet
H975	1340-01-269-1446	M274 Smoke Sig Prac	Mod 3	Wood	4	Army	60 per pallet
HA13	1340-01-449-1240	M274 Smoke Sig Prac	Mod 4	Wood	4	Army	60 per pallet
H165	1340-01-379-7814	M261 MPSM HE/M439	Mod 3	Fastpack	48	Army	48 per pallet
HA14	1340-01-446-4095	M261 MPSM HE/M439	Mod 4	Fastpack	48	Army	48 per pallet
H165	1340-01-269-1447	M261 MPSM HE/M439	Mod 3	Wood	4	Army	60 per pallet
HA14	1340-01-448-8891	M261 MPSM HE/M439	Mod 4	Wood	4	Army	60 per pallet
H974	1340-01-379-7889	M267 MPSM Prac/M439	Mod 3	Fastpack	48	Army	48 per pallet
HA17	1340-01-448-7506	M267 MPSM Prac/M439	Mod 4	Fastpack	48	Army	48 per pallet
H974	1340-01-268-7174	M267 MPSM Prac/M439	Mod 3	Wood	4	Army	60 per pallet
HA17	1340-01-448-7507	M267 MPSM Prac/M439	Mod 4	Wood	4	Army	60 per pallet
H183	1340-01-268-7175	M257 ILL Flare/M442	Mod 3	Wood	3	Army	45 per pallet
HA18	1340-01-448-8890	M257 ILL Flare/M442	Mod 4	Wood	3	Army	45 per pallet
H184	1340-01-286-4719	M264 RP Smoke/M439	Mod 3	Fastpack	48	Army	48 per pallet
HA15	1340-01-446-4097	M264 RP Smoke/M439	Mod 4	Fastpack	48	Army	48 per pallet
Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
H154	1340-01-371-8611	M278 IR Flare/M442	Mod 2	Wood	3	SOF	45 per pallet
HA10	1340-01-446-2905	M278 IR Flare/M442	Mod 4	Wood	3	SOF	45 per pallet
H163	1340-01-108-8851	M151 HE/M423 PD	Mod 1	Wood	4	SOF
H583	1340-01-269-9123	M151 HE/M423 PD	Mod 3	Wood	4	SOF	60 per pallet
H642	1340-01-309-8300	M229 HE/M423 PD	Mod 2	Wood	4	SOF	60 per pallet
HA09	1340-01-446-2902	M229 HE/M423 PD	Mod 4	Wood	4	SOF	60 per pallet
H462	1340-01-309-5799	M255A1 Flechette/M439	Mod 2	Wood	4	SOF	60 per pallet
HA11	1340-01-446-2901	M255A1 Flechette/M439	Mod 4	Wood	4	SOF	60 per pallet
Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
H663	1340-01-014-5421	WTU-1/B		Wood	4	Navy	192 per pallet
H812	1340-01-338-6482	M257 ILL Flare/M442		Metal	4	Navy	80 per pallet
HA06	1340-01-412-9346	M278 IR Flare/M442		Metal	4	Navy	80 per pallet
HA03	1340-01-416-1878		Mod 2	Metal	4	Navy	80 per pallet
HA07	1340-01-424-5819		Mod 4	Metal	4	Navy	80 per pallet
Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
H812	1340-01-456-0978	M257 ILL Flare/M442		Wood	6	Air Force	90 per pallet
H872	1340-01-309-5799	M274 Smoke Sig Prac		Wood		Air Force	120 per pallet
HA06	1340-01-443-3583	M278 IR Flare/M442		Wood	6	Air Force	90 per pallet
J147	1340-01-154-1679		Mod 2	Wood	6	Air Force	90 per pallet
HA07	1340-01-446-4096		Mod 4	Wood	6	Air Force	90 per pallet
Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
HA12	1340-01-446-7680	M151 HE/M423 PD	Mod 4	Fastpack	48	Army	48 per pallet
HA12	1340-01-448-8889	M151 HE/M423 PD	Mod 4	Wood	4	Army	60 per pallet
HA13	1340-01-446-4094	M274 Sig Prac Smoke	Mod 4	Fastpack	48	Army	48 per pallet
HA13	1340-01-449-1240	M274 Sig Prac Smoke	Mod 4	Wood	4	Army	60 per pallet
HA14	1340-01-446-4095	M261 MPSM HE/M439	Mod 4	Fastpack	48	Army	48 per pallet
HA14	1340-01-448-8891	M261 MPSM HE/M439	Mod 4	Wood	4	Army	60 per pallet
HA17	1340-01-448-7506	M267 MPSM Prac/M439	Mod 4	Fastpack	48	Army	48 per pallet
HA17	1340-01-448-7507	M267 MPSM Prac/M439	Mod 4	Wood	4	Army	60 per pallet
HA18	1340-01-448-8890	M257 ILL Flare/M442	Mod 4	Wood	3	Army	45 per pallet
HA15	1340-01-446-4097	M264 RP Smoke/M439	Mod 4	Fastpack	48	Army	48 per pallet
Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
HA09	1340-01-446-2902	M229 HE/M423 PD	Mod 4	Wood	4	SOF	60 per pallet
HA10	1340-01-446-2905	M278 IR Flare/M442	Mod 4	Wood	3	SOF	45 per pallet
HA11	1340-01-446-2901	M255A1 Flechette/M439	Mod 4	Wood	4	SOF	60 per pallet
Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
HA03	1340-01-416-1878		Mod 4	Metal	4	Navy	60 per pallet
HA06	1340-01-412-9346	M278 IR Flare/M442		Metal	4	Navy	60 per pallet
HA07	1340-01-424-5819		Mod 4	Metal	4	Navy	60 per pallet
Dodic	NSN	Warhead/fuze	Mk66 Motor	Pack	Qty	User	Pallet pack
HA06	1340-01-443-3583	M278 IR Flare/M442		Wood	6	Air Force	90 per pallet
HA07	1340-01-446-4096		Mod 4	Wood	6	Air Force	90 per pallet

Table 5-7 DODIC/NSN cross reference for all HYDRA-70 2.75 inch rocket items which are in the inventory presently or which will soon be fielded.

NOTE: Due to the various models of rockets, warheads, and fuze combinations possible and the number of those that are undergoing classification or awaiting production contracts, a truly comprehensive list is not possible at this time. TM 43-0001-30 gives additional information on rockets and rocket systems, fuzes, and motors. To obtain additional information about the Hydra 70, 2.75-inch rocket, write the US Army Industrial Operations Command , ATTN: AMSIO-PM-RO, Rock Island, IL 61299-6000 and/or see their website at www.ioc.army.mil/sm/hydra.

Section III. Missiles

5-8. MISSILE CONFIGURATIONS

The Hellfire surface attack guided missile is currently available in three configurations: dummy, training, and tactical. There are two basic tactical missile types: Semi-active laser (SAL) and Radar Frequency (RF). All Hellfire missiles are 7 inches in diameter, and have a wingspan of 12.9 inches. The missile, depending on the model, weighs 100 to 108 pounds with an overall length of 64 to 71 inches. Color codes and data markings for the Hellfire missile are as follows:

• The basic color of missile is black.

• Data markings are olive drab.

• Markings on the aft end are four brown 3-inch squares 90 degrees apart (brown means solid propellent).

• Markings on the end of the warhead are four yellow 3-inch squares 90 degrees apart (yellow means HE).

• The basic color of container is olive drab.

a. Dummy Missiles. The M34 dummy missile has the same physical characteristics as the tactical missile. It is used to train armament personnel in loading and unloading and to simulate aircraft missile loads for training flights.

b. Training Missiles. The M36 training missile is used for captive flight training and cannot be launched. It has an operational laser seeker that can search for and lock on laser energy. The M36 has the same physical characteristics as the tactical missile but contains no explosives. It requires the same handling as a live tactical missile.

NOTE: If a training missile is on a launcher rail, live missiles cannot be launched.

c. Tactical Missiles.

(1) The AGM-114A tactical missile, DODIC number PA79 and NSN 1410-01-126-4662, is the originally designed Hellfire missile, which is no longer in production. AGM-114As in the inventory are released for live-fire training when they are replaced with AGM-114Cs.

(2) The AGM-114B, DODIC number PC9l and NSN 1410-01-146-9668, although primarily designed for Navy use, can be fired from Army aircraft. This missile has an additional electronic arm/safety device required for shipboard use.

(3) The AGM-114C missile, DODIC number PD68 and NSN 1410-01-192-0293, has an improved semiactive laser seeker with an improved low visibility capability. The AGM-114C has a low smoke motor and a lower trajectory than the 114A. Army missiles should be marked with either the A or C designation just behind the seeker.

(4) The AGM-114F missile, DODIC number PV29 and NSN 1410-01-332-2471, features two warheads, a seeker and an autopilot similar to the C-model missile. The 114F is designed to defeat vehicles equipped with reactive armor.

(5) The AGM-114K missile, DODIC number PV30 and NSN 1410-01-381-0715, features dual warheads for defeating reactive armor, electro-optical countermeasures hardening, semiactive laser seeker, and a programmable autopilot for trajectory shaping. The AGM-114K missile is capable of operating with either pulsed radar frequency or A-Code laser codes for those aircraft equipped with dual code capability.

NOTE: When A-Code is used with the AGM-114K, the missile counter-counter measure switch should remain OFF for both electronic counter measure and non-ECM environments. This procedure is not applicable if PRF coding is used.

(6) The AGM-114L missile, DODIC number PU55 and NSN 1410-01-399-7459, uses an active radar frequency signal to detect and track targets. It emits RF energy and homes-in on the reflected RF energy. It is an active (emitting) missile that is inertially guided and radar assisted.

(7) The AGM-114M missile, DODIC number WF15 and NSN 1410-01-464-9031, has a HE fragmentary warhead and is designed for naval use. This Hellfire model flies the same profile as the AGM-114K and its weight roughly equals the AGM-114F. At present, the U.S. Navy is the only branch which has this model in its inventory.

(8) For antiarmor roles, the AGM-114 missile has a conical shaped charge warhead with a copper liner cone that forms the jet that provides armor penetration. This high explosive, antitank warhead is effective against various types of armor including appliqué and reactive. Actual penetration performance is classified. It can also be employed against concrete bunkers and similar fortifications. The AGM-114F, 114K, and 114L use the same shape charge warhead as the 114C. In addition, they contain a small warhead mounted forward of the main warhead to provide enhanced performance against reactive armor.

(9) The tactical missiles are propelled by a single stage, single thrust, solid propellant motor. When thrust exceeds 500 to 600 pounds, the missile leaves the rail. Based on a 10g acceleration parameter, arming occurs between 150 to 300 meters after launch. Thrust duration is approximately 2 to 3 seconds and maximum velocity of the missile is 950 miles per hour (475m/sec or Mach 1.4). Figure 5-9 shows the Hellfire missile models with the exception of the AGM-114M.

Figure 5-9. Hellfire missile models.

5-9. SEMI-ACTIVE LASER (SAL) HELLFIRE MISSILE PERFORMANCE

a. Maximum Standoff Range. Maximum standoff range is a function of missile performance, launch platform altitude versus target altitude, visibility and cloud cover. The effects of cloud ceilings on maximum standoff ranges and the launch envelope for all lock on before launch (LOBL) shots are shown in Figures 5-10a and 5-10b. The effects of cloud ceilings on maximum standoff ranges and the launch envelope for lock on after launch (LOAL-Direct) are shown in Figures 5-11a and 5-11b. The effects of cloud ceilings and the launch envelopes for lock on after launch (LOAL-LO and HI) are shown in figures 5-12a, 5-12b, 5-13a and 5-13b respectively.

(1) Autonomous. The target should be designated by the launching aircraft when the aircraft can fire from a position close enough to the target to ensure accurate designation without extensive exposure of the launching aircraft to the enemy threat. On a clear day, target designation is limited by the capability of the designator to maintain the total laser spot on the target. Table 5-7 shows Hellfire laser designation times.

Range (meters)	Max Delay Time (sec)	Offset Lasing Time (sec)	Transition Time (sec)	On Target Time (sec)	Total Lasing Time (sec)	Temp (^OC) and Approximate TOF (sec) -32^O+21^O +52^O
2000	2*	0	0	4	4	7	6	6
3000	2*	0	2	6	8	11	10	10
4000	5	1	2	6	9	15	14	13
5000	7	3	2	6	11	21	18	17
6000	10	5	2	6	13	28	23	22
7000	12	8	2	7	17	36	29	27
8000**	15	12	2	8	22	45	37	34
All times are from missile separation. Add an additional second for time from trigger pull. * This is also the minimum time. It is not recommended to use delay times of less than 2 seconds (3 seconds from trigger pull) because this may allow the missile seeker to lock onto backscatter near the aircraft! ** Indirect only.

Table 5-7. SAL HELLFIRE Designation Times

Under some atmospheric conditions and aircraft-to-target positions, it is possible for an AH-64 SAL Hellfire missile to fly through the TADS FOV and for the missile exhaust to obscure the target. When designation is autonomous, this can cause the TADS to break lock and disrupt the missile flight. This phenomenon can be avoided by rotating the aircraft just before launch at least 3.0° to 5.0° in the direction of the missile to be fired so that the missile does not fly through the TADS FOV. If TADS break-lock should occur, continue to manually track the target until accurate TADS IAT is reestablished. For a high Ph the maximum effective autonomous engagement range that the missile can be launched from is limited by the TADS ability to accurately maintain the laser spot on the target and the seeker's ability to lock-onto the reflected laser energy. Refer to Table 5-7a below.

Sight	Track Mode	Max Autonomous Designation Range (KM)
Day TV	Auto Track	6.0
Day TV	Manual	4.0
FLIR	Auto Track	3.5
FLIR	Manual	3.0
DVO	Manual	3.0

Table 5-7a. SAL Hellfire Maximum Autonomous Designation Range

for High Probability of Hit (Ph)

(2) Remote. Remote designation allows the launch aircraft to stand off at greater distances from the target. This standoff range can be out to the maximum missile effective engagement range. Remote designation also allows the launch aircraft to be masked from the target using the LOAL-LO or LOAL-HI launch mode (Figures 5-12a, 12b, 13a and 13b respectively). Remote designation also allows a single aircraft to provide the weapons for several designators. Remote designators may include another aircraft, a ground or vehicle laser locator designator, or one of the various designators of other services or foreign allies. Remote designators must be within their maximum designation range from the target, as determined by their laser beam divergence and aiming errors (jitter and boresight). Range to target can vary from one type of designator to another.

This chart shows C model missile trajectories.

*F model flies approximately

100 feet lower than 114C.

K model LOBL trajectories: 3 Km = 300 feet above launch point.

5 Km = 500 feet above launch point.

7 Km = 600 feet above launch point.

Figure 5-10a. Minimum Cloud Ceiling – LOBL

Figure 5-10b. Launch Envelope – LOBL

Figure 5-11a. Minimum Cloud Ceilings – LOAL DIR

Figure 5-11b. Launch Envelope – LOAL DIR

Figure 5-12a. Minimum Cloud Ceilings - LOAL LO

Figure 5-12b. Launch Envelope – LOAL LO

Figure 5-13a. Minimum Cloud Ceiling – LOAL HI

Figure 5-13b Launch Envelope –LOAL HI

Figure 5-14. Maximum Designator Offset Angle for SAL Hellfire.

b. Remote Designator Location Offset. When the remote designator is located in an offset position in azimuth from the launch aircraft, care must be taken to ensure that the laser spot is on a section of the target that is visible to the missile. The remote designator should not be displaced more than ±60 degrees in azimuth from the launch aircraft to the target line.

c. Remote Designator Safety Zone. The crew of the designating aircraft should ensure that it is not inside the + 30 degrees designator avoidance area (Figure 5-15). If the designating aircraft is unable to designate outside of the avoidance area, the minimum laser delay time must be accurately computed and utilized. WARNING! Firers and designators must use this minimum delay time because a lesser delay time might cause a remotely fired missile to impact the designator resulting in needless loss of life and assets! The difference in time of flight for a missile launched from the designator's position and the launching platform site is the minimum delay that must be adhered to. Follow the guidelines shown in Figure 5-15. Units may be forced to use this method in constricting terrain, therefore careful engagement area planning must be utilized.

.

d. Minimum Engagement Range. Due to the SAL Hellfire missile's trajectory shaping and seeker scan pattern during LOAL mode, it will be necessary to increase the minimum engagement ranges as the launch altitude increases above the target altitude. As launch altitude increases the missiles ability to see the target at shorter ranges decreases. The minimum LOAL engagement ranges shown in Table 5-8 are for launch altitudes less than 50 feet above target altitude. Increase these minimum ranges by 0.5 KM for altitudes of 50-400 feet and by 1.0 KM for altitudes 401-800 feet above the target. Minimum LOBL target engagement ranges are shown in Table 5-9. Maximum missile altitude is shown in Table 5-10.

Warning! If unable to remain outside + or – 30 degrees, you must utilize the minimum delay time.

Remote designator should remain outside + or – 30 degrees (gun to target line)!

Figure 5-15. Designator avoidance area for SAL Hellfire.

MISSILE	AZIMUTH TARGET OFFSET (degrees)	MINIMUM LOAL ENGAGEMENT RANGE (KM) LAUNCH ALTITUDE < 50' ABOVE TARGET ALTITUDE LOAL - DIR LOAL - LO LOAL - HI
AGM-114A	0^O 7.5^O	2.0 2.5	2.0 3.0	3.5 4.5
AGM-114C	0^O 7.5^O	1.9 2.0	2.0 3.0	3.5 4.5
AGM-114F	0^O 7.5^O	2.0 2.5	2.5 3.5	3.5 4.5
AGM-114K	0^O 7.5^O	1.5 1.7	2.0 2.5	3.5 3.5
50' - 400' Increase minimum range by 0.5 KM. 401' - 800' Increase minimum range by 1.0 KM.
Table 5-8. Minimum LOAL target engagement range

MISSILE	MINIMUM RANGE (KM) 0^OTarget Offset in Azimuth	MINIMUM RANGE (KM) 20^OTarget Offset in Azimuth
AGM-114A	0.8	1.2
AGM-114C	0.8	1.2
AGM-114F	1.4	1.5
AGM-114K	0.5	0.7
Table 5-9. Minimum LOBL target engagement range.

MODE	LOBL			LOAL-DIR		LOAL-LO		LOAL-HI
TARGET RANGE (KM)	3	5	7	7		8		8
LASER DELAY (SEC)	0	0	0	2	12	4	15	4	15
MISSILE TYPE	MAXIMUM MISSILE ALTITUDE INCLUDING RANDOM TRAJECTORY (FEET)
AGM-114A	400	1000	1700	1700	1000	1900	1400	2300	2200
AGM-114C	500	1100	1800	1200	500	1500	900	1800	1500
AGM-114F	400	1000	1700	1200	300	1300	700	1600	1300
AGM-114K	400	600	700	600	500	900	800	1500	1500

Table 5-10. Maximum Missile Altitude

5-10. SAL HELLFIRE MISSILE PERFORMANCE DETRACTORS

a. Backscatter Backscatter is a term that applies to a portion of the laser beam energy reflected off atmospheric particles in the laser path back towards the designator while the remainder of the laser energy penetrates toward the target. Backscatter occurs even in clear weather so the operator must rely upon LOBL constraints box to know if the seeker is tracking backscatter. Obscurants in the laser-to-target line of sight can also cause backscatter (fog, haze, snow, smoke, dust, etc.). If a target return is not detected then the seeker may track the backscatter return. If the seeker is tracking backscatter, the seeker LOS and the designator LOS will differ by more than 2 degrees and the LOBL constraints box will be dashed.

(1) If an obscurant is between the designator and the target, it is possible for the seeker to lock on the reflected laser energy from the obscurant and "walk up" the laser beam toward the aircraft. When the seeker LOS is 2 degrees from the designator LOS and the seeker is locked on the autonomous laser spot, the symbology will indicate "OUT OF CONSTRAINTS."

NOTE: This symbology is only correct in this case if the aircraft is pointing directly at the target.

(2) Backscatter is best controlled by maintaining the true target in the seeker's instantaneous field-of-view. The seeker generally does not track backscatter after track has been established on the true target. Backscatter tracking is more likely to occur with autonomous lasing than with remote lasing because of the proximity of the seeker to the laser beam on the launch aircraft. Backscatter affects LOBL autonomous but can also affect LOAL autonomous if the designation commences before the missile has time to climb above and away from the laser beam.

b. Backscatter Avoidance Techniques.

(1) To eliminate a backscatter lock-on, lasing the target should be discontinued for a short period of time and the target redesignated. If a backscatter problem still exists, it may be necessary to discontinue lasing, move to another position, and redesignate the target.

(2) If the launching aircraft is designating the target and autonomous operation is properly set up, one seeker will be slaved to the designator LOS, such as pointed at the target when designator is tracking the target. This condition will generally result in proper seeker lock-on to the target. However, under some conditions that fail to produce a detectable target return, the seeker will lock onto the laser backscatter close to the aircraft. Generally, backcatter is caused by poor target reflectivity, collocated obscurants, or excessive designation ranges. If backscatter occurs, the seeker LOS will diverge from the designator LOS by two or more degrees, the LOBL constraints symbology will indicate "OUT-OF-CONSTRAINTS" and the missile should not be launched.

NOTE: If primary channel track is achieved and the symbology indicates "OUT-OF-CONSTRAINTS", the missile cannot be launched by pulling the trigger to the first detent but can be launched by pulling the trigger to the second detent. The missile should not be launched by pulling the trigger to the second detent when "OUT-OF-CONSTRAINTS" is indicated, because it will result in a low probability of hitting the target. If the LOBL constraints box is intermittently switching "in-and-out" of constraints, then a marginal target condition exists and the missile should not be launched.

(3) To eliminate a backscatter lock-on, stop lasing the target. Switch to LOAL-Direct and use a minimum of 2 seconds of delayed designation from separation (approximately 3 seconds after trigger pull).

(4) If time permits, an attempt to improve the target return could be made by reducing engagement range, improving aim point or employing offset designation onto the higher reflective terrain near the target. The laser must be turned off before the reengagement of any target to allow the seeker to unlock from the backscatter.

(5) It is possible for the seeker to switch to tracking backscatter during the first second after missile separation in the LOBL autonomous mode if the target return is lost before the missile has climbed above the laser beam. This condition can be created by image auto track break lock due to motor smoke in the TADS LOS. The aircraft should be rotated 3 - 5 degrees in the direction of the missile to be launched to ensure that the missile does not fly across the TADS LOS and create an IAT breaklock or degrade the TADS imagery.

c. Rules for Operation in Obscurants. Performance is reduced when obscurants degrade the seeker's lock-on range. The following rules indicate how to determine if the situation supports a missile launch.

(1) The designator operator must have a clear enough image of the target for accurate placement of the laser spot on the target without overspill or underspill.

(2) When the launch aircraft has a line-of-sight to the target, it must have a sufficient image in its day television or forward looking infared so that the general shape of the target is recognizable. If the launch aircraft is masked, the designating aircraft must have a sufficient image in its DTV or FLIR for the aircrew to recognize the general shape of the target. Otherwise, the seeker will probably not achieve a lock-on, even after launch.

(3) Laser range finder readings should be taken by the designating aircraft and the missile not launched until steady, plausible range readings are indicated. Erratic range readings are generally caused by smoke or dust near the target. The same erratic readings could also be caused by overspill or underspill onto foreground or background objects. If accurate designation does not fix the problem, then the only solution is to change to a different designator, a different target, or relocate the designating aircraft.

(4) For LOBL autonomous launches, constraints symbology must show "in constraints." Otherwise, the seeker is not tracking the true target.

c. Target Illumination.

(1) Only the target is illuminated by the laser spot. When the missile is in its last few seconds of flight before impact, the entire laser spot must be placed on the target. During the final few seconds of flight, even a momentary placement of laser energy on adjacent terrain can prevent the missile from hitting the target. Once the seeker is tracking, the designator should not be turned off before all in-flight missiles have impacted. The seeker will not initiate box scan once the laser energy is lost.

(2) The portion of the target that is illuminated must be "seen" by the missile. This requirement imposes a 60-degree limit on the angle between the gun target line and the remote designator-to-target line. The probability of killing a target depends on missile flight path at impact and target attack azimuth but generally is maximized if the laser spot can be held stable on the base of the tank turret.

(a) Boresight error. Boresight error occurs when the laser spot is not properly aligned with the TADS reticle, which produces an error in the location of the spot on the target. Boresight error can and will cause a SAL Hellfire missile to miss its intended target. If you eliminate boresight error, you have eliminated one of the most fundamental errors that crews make. Know how your unit plans to accomplish outfront boresighting. If there is no good plan, create one. Allocate time for internal and outfront boresighting in your mission planning and correctly complete both internal and outfront boresight procedures for your aircraft. Sharp knives cut the deepest! (Also, see note on trends in the preface.)

(b) Spot jitter. Spot jitter is the result of motion of the designator or the beam developed by the designator around the intended aim point. Spot jitter can give the laser spot a bouncing movement on the target, which will increase with designator distance from the target.

(c) Beam divergence. The further the laser designator is from the target, the wider the spot will be on the target. The amount of beam divergence will vary between different types of designators.

(d) Attenuation. Attenuation is a portion of the laser beam that is "scattered" by obscurants along the laser-to-target LOS and the missile-to-target LOS resulting in a reduced target pulse to the seeker. Also, low visibility attenuates the target return to the seeker. If the attenuation is severe, the seeker will not detect the laser energy from the target.

(e) Overspill. Overspill is caused by placing the laser spot too high on the target so that beam divergence and jitter cause the spot or a portion of the spot to spill over onto the object or the terrain behind the target. Overspill can cause intermittent background false targets, which become more severe at long designation ranges.

(f) Underspill. Underspill is caused by placing the laser spot too low on the target so that the spot or a portion of the spot spills onto the foreground. Underspill can cause foreground false targets, which become more severe at long designation ranges.

NOTE: Even a small number of overspilled or underspilled laser pulses can cause the missile to follow false signals. If either of these conditions occur just before missile impact, the probability of hit (Ph) is seriously degraded.

5-11. RADAR FREQUENCY (RF) HELLFIRE MISSILE CHARACTERISTICS AND

PERFORMANCE

Figure 5-16. RF Missile Operational Concept

a. The RF Hellfire missile uses an active radar frequency signal to detect and track targets. It emits RF energy and homes-in on the reflected RF energy. It is an active (emitting) missile that is inertially guided and radar assisted. The missile radar seeker transmits frequencies within the millimeter wave Ka-band, around 35 GHz. This frequency band was chosen for several reasons. A relatively narrow radar beamwidth can be developed using Ka-band frequencies while keeping the size of the radar antenna small. A narrow beamwidth is desirable because it concentrates more of the available transmit power on the target of interest while minimizing interference from nearby clutter. The use of Ka-band frequencies also takes advantage of a relative notch in the tendency of atmospheric water vapor to absorb radar signals which improves the missiles capability to operate in all weather environments as well as smoke.

b. The primary armament system of AH-64D is the Longbow Hellfire Modular Missile System (LBHMMS). Crews of the AH-64D can fire all variants of the Semi-Active Laser (SAL) missile and the Radar Frequency (RF) missiles. The Longbow RF missile is capable of engaging moving and stationary targets at ranges between 0.5 and 8.0 KM. The LBHMMS consists of M299 launchers mounted on any of the four wing stations. The M299 launcher is a modified M272 launcher that has the capability to launch both SAL and RF Hellfire missiles. The M299 launcher cannot be used on the AH-64A and the M272 launcher, cannot be used on the AH-64D. The M272 cannot launch the RF missile.

Figure 5-17. RF Radiation Hazard Areas

c. During missile operation, the RF radiation hazard area should be avoided. This area extends from the missile nose outward one meter and 45° polar from the missile centerline.

d. The RF Missile operates in three modes; Standby, Prelaunch, and Postlaunch.

(1) Standby Mode: After the missile completes power-up and PBIT, it will enter and remain in the standby mode until it receives target data (handover) from the WP.

(a). On aircraft power up, the missiles begin a startup process. During startup, the missiles initiate a power up sequence, initialize in the standby mode, perform BIT, and inform the WP that startup is complete and it is in the standby mode.

(b). A Transfer Alignment (TA) is completed immediately after the power-up BIT sequence. TA allows the missile to receive continuously updated inertial position, acceleration, and velocity data from the aircraft to align its own Inertial Navigation System (INS).

(c). The TA process accounts for known mechanical alignments between the systems, pylon articulation and communications delays.

(d). The attitude and velocity of the missile are maintained during the TA function. While the missile is in the standby mode and ready, it will display an “R” in its missile icon.

(e). TA compares attitude and velocity measurements from the Longbow EGI to the missile INS, and updates it to the aircraft reference. Items included in the TA message are:

Pitch and roll angle

True heading angle

Aircraft longitudinal, lateral, and vertical velocity

INU time tag

Pressure and density altitude

Static temperature

Pylon position relative to ADL

Pylon position time tag (articulation with ACFT pitch and roll rates)

Aircraft pitch, roll, and yaw rate

Aircraft estimated heading error

(2) Prelaunch Mode. Actioning the missile system with acceptable target data (Target Handover) will initiate the missile prelaunch mode. Prelaunch mode occurs from the time the WP transfers target data to the missile until the missile is either launched or returns to the standby mode.

(3) Postlaunch Mode. The postlaunch mode is initiated when the firing command (weapon trigger pull) occurs. The WP verifies launch conatraints (saftey and performance inhibits, launcher and missile BIT status, missile gimbal angles, and RF tracking status for LOBL missiles) and, if no constraints are active, issues the release consent message to the launcher. Upon reciept of the release consent message, the launcher issues the launch command to the designated missile and, at the same time, issues commands to enable the missile battery and pneumatic actuator control system. When the launch commands are received by the missile, the system mode transitions to postlaunch. The launcher verifies battery power and, if valid, the digital communications with the missile ceases and the motor fire command is sent to the missile. The missile acheives umbical separation and leaves the rail approximately one second after the launch command is issued. The warhead is armed when the missile achieves 10 g’s acceleration (150 to 300 meters).

Figure 5-18. Target Handover

e. The missile receives a target handover three ways, either directly from the aircraft’s own FCR or from the WP based on TADS information or data received via the IDM.

The target handover message defines the target position and velocity vector, current at the time of the assignment. The launcher receives the target assignment from the acquisition sensor or WP. The launcher then forwards the data to the priority missile. The missile remains in the standby mode until a handover message is received and then immediately transitions to the prelaunch mode. The target handover contains the following information:

Target status- ID, target type (air/ground), LOBL inhibit (on/off)

Tgt detection time- time from initial detection until current update

Tgt update time- time since last update

Tgt NED position- NED at time of detection

Updated NED position- NED position at update time

Tgt NED velocity

Cross-range- handover data for cross-range

Height- handover data for height

Range- handover data for range

Range rate- handover data for radial velocity

Cross-range- handover data for cross-range velocity

Aircraft time at request

The three types of target handovers are:

(1) FCR. When the selected sight is FCR, and the 2ND TARGET INHIBIT mode is not selected, the WP transfers target data for both a primary and secondary target when the targets are detected. If the primary target is stationary, a second stationary target may be supplied to the missile. This is the only mode of the three that supplies a secondary target.

If the Hellfire system is actioned prior to an FCR scan the WP initiates the target handover at the completion of the scan. If the Hellfire system is actioned during an FCR scan, the WP initiates handover of the NTS target immediately based on the targets detected up to that point, with subsequent ANTS target handovers occurring after completion of the first far bar scan.

(2) TADS. When TADS is the selected sight and the actioned missile type is RF, the “TARGET DATA ?” performance inhibit will be displayed. The target must be designated for approximately 3.0 seconds to receive the target handover and remove the “TARGET DATA ?” message. If the laser data is erratic the message will not be removed and the handover will not occur until valid range is acquired.

(3) IDM. When the target handover is received via the IDM (RFHO), and the mission is accepted the RF handover data represents the target NED coordinates relative to the receiving aircraft. To receive an IDM target handover in an aircraft with or without radar, you must have the FCR as your selected sight and the missiles WAS’d. You must press rec button, prior to selecting FCR as sight (w/o).

Moving Stationary	LOBL
	LOBL	LOBL/LOAL	LOAL
0.5	1.0	2.5	8

Table 5-11. Target Range in KM

f. After the WP transfers target NED data to the missile, the missile determines the launch mode; either LOBL or LOAL based on target velocities (moving or stationary) and range to target. The FCR target symbols that are displayed do not determine the type of missile mode for launch (i.e. LOBL/LOAL). Therefore, it is possible to launch a LOBL missile at a LOAL target symbol and vice versa. During prelaunch LOBL operation, if the missile radar fails to acquire the target after three attempts the radar will transition to standby but the inertial tracking of the target will continue. If the missile determines the target requires a LOBL acquisition, it will try to acquire it by radiating three consecutive times for approximately 3.0 seconds each. Actioning the missile system again would allow for three more scan attempts on the same priority target.

g. The Longbow RF missile is capable of engaging moving and stationary targets at ranges between 0.5 and 8.0 KM. The resulting missile performance against these targets is a function of many factors; the most important of which is the target handover error at the start of the target acquisition process. The target handover error grows as the time between FCR detect and the missiles receipt of the target handover increases. In the example above, the time between accepting the IDM RFHO and the time the actual target handover occurs (WASing) could cause an acquisition attempt in the wrong area. It is very important to minimize this handover latency for best performance, however, the missile does optimize its performance by selecting the appropriate acquisition mode and sub-mode for best target detection and tracking performance based on handover latency and initial target handover error.

Figure 5-19. Moving Target Handover Delay

h. RF Missile Trajectories. The Longbow Hellfire missile flies a trajectory that is optimized for radar performance while maintaining lethality. The LOBL and LOAL elevation flight profiles are similar.

Figure 5-21. RF Missile Elevation Flight Profiles

Figure 5-22. Direct Trajectory for RF LOBL

Moving (LOBL) target azimuth flight profiles. The missile flies a very direct azimuth flight profile for LOBL operations. If the target becomes stationary after launch, an off-axis trajectory is possible. See figure 5-22 on page 5-43.

Figure 5-23. RF Missile Moving Target Azimuth Flight Profiles

Figure 5-23 shows the moving target azimuth profiles for a 20° offset angle. As the offset angle decreases, the trajectory is closer to the armament datum line.

Figure 5-24. RF Missile Stationary Target Azimuth Flight Profiles w/1.0º Offset Angle.

Figure 5-24 shows the stationary (LOAL) target azimuth flight profiles. The LOAL azimuth flight profile is driven by a Doppler Beam Sharpening (DBS) trajectory, which is used for medium to long range stationary targets. This illustration shows trajectories with a 1.0° offset angle.

Figure 5-25. RF Missile Stationary Target Azimuth Flight Profiles w/20º Offset Angle.

Figure 5-25 shows that increasing the offset angle will increase the distance of the trajectory from the armament-datum line.

Figure 5-26. RF Missile Modes.

i. RF Missile Radar Modes. The target acquisition and tracking modes are terms used to explain the different ways the missile seeker improves its chances of locating and hitting LOBL and LOAL targets. The missile radar has three target acquisition modes tailored to specific target characteristics. All modes require a target handover from the WP. Terminal Track Acquisition (TTA) for short-range stationary targets (LOAL and LOBL). Preterminal Track Acquisition (PTA) for long range stationary targets (LOAL). Moving Target Acquisition (MTA) for moving targets (LOBL). The missile has two tracking modes, Preterminal Track (PTT), and Terminal Track (TT). The two stationary target acquisition modes (PTA, TTA) use different types of processing to separate targets from the surrounding clutter based on range. Terminal Track Acquisition (TTA): The TTA mode utilizes High Range Resolution (HRR) to process targets from 0.5 to 2.5 KM for both LOBL and LOAL short-range targets. The missile can not perform Doppler Beam Sharpening (DBS) trajectory on short-range targets under 2.5 KM. HRR is utilized to detect stationary targets in ground clutter by providing much tighter range bins per range gate. This technique produces a much better resolution of the designated target. With smaller range bins this mode assist target detection by measuring the size of the radar return for comparison with target handover classification. The LOAL mode is exercised at ranges greater than 1.0 KM to meet performance requirements for longer-range HRR operations and reduced RCS targets. For targets between 1.0 and 2.5 KM a LOAL status will be supplied to the launch platform; however, the radar will immediately attempt to acquire and track the target (LOBL). This is why between the ranges of 1.0 and 2.5 KM the missile mode can be either LOAL or LOBL. Preterminal Track Acquisition (PTA). PTA is designed to acquire long-range stationary targets in the LOAL mode at ranges between 2.5 to 8.0 KM using a technique called Doppler Beam Sharpening (DBS).

Figure 5-27. Doppler Beam Sharpening.

j. Doppler Beam Sharpening (DBS). DBS uses a curved trajectory to induce relative motion between a stationary target and its background by flying an off-axis flight path to the target. DBS significantly enhances the probability of detection and tracking stationary targets at long ranges. Standard doppler processing (missile flying direct to the target) would cause a stationary target to be included in the same doppler bin as all of the mainlobe clutter return since both types of return exhibit the same relative range rate. DBS, due to the angular difference between the missile’s forward velocity vector and the target LOS, causes the relative range rate of the target to be different than that of the background, spreading the return over many doppler bins. The resulting spread increases the target signal to clutter ratio in the target doppler bin, enabling the radar to identify and locate the target. DBS is selected for ground clutter rejection during stationary target Pre-Terminal Track (PTT) or when a target that was initially an MTI has become an STI during flight. If this occurs the missile would switch from a straight trajectory to a DBS trajectory in-flight. There are two constraints involved when evoking the in-flight DBS switch option. First, the switch is not allowed near the terminal phase where missile kinematics cannot support the trajectory switch. Second, the trajectory will not switch from DBS back to a straight trajectory. The probability of an in-flight DBS is very low.

Figure 5-28. DBS Trajectory.

k. DBS Trajectory. The missile does not always turn in the same direction when DBS occurs. The direction of the turn is determined at umbilical separation as a function of the LOS to the target. Missiles launched from either side of the aircraft will follow the same trajectory based on the following data. If the target is right of the missile centerline the missile trajectory curve will be a left DBS trajectory to the target. If the target is left of the missile centerline the missile trajectory curve will be a right DBS trajectory to the target. Targets close to the zero bearing may yield either a left or a right DBS trajectory. In the event the missile loses radar track of the target, it will shift to DBS in an attempt to re-acquire the target. The primary parameters used to determine the extent of the DBS trajectory are the inertial guidance data of the missile (where it is at that instant), the last known point of the target (point the missile is tracking to), and, for moving targets, the last known velocity of the target. In the event the missile does not re-acquire the target, it will use inertial guidance to fly to the calculated target location.

5-12. TOW MISSILE

a. The TOW surface attack guided missile is an antitank weapon that may also be used against bunkers and similar fortifications, depending on the tactical situation.

(1) When the trigger is pulled, three batteries are activated that provide power to the electronics, the Xenon or thermal beacon, and the actuator subsystem. When the missile is fired, the launch motor develops initial thrust to accelerate the missile to approximately 250 feet per second when it exits the tube. The wings on the missile extend as it exits the tube and completes the circuit to activate the flight motor about 7 meters from the launcher. The warhead becomes armed between 30 and 65 meters from the launcher. Acceleration provides peak velocity at approximately 350 meters.

(2) Upon capture, the TOW missile becomes a closed loop system. The Xenon beacon and thermal beacon (TOW 2/TOW 2A) are installed in the rear of the missiles and are detected by the Xenon detector or thermal tracker located in the telescopic sight unit. Two wire dispensers are mounted on the rear of the missile at the 90- and 270-degree positions. These dispensers contain 3,750 meters of single strand wire. Control surface flippers respond to signals from this wire command link. Helium powers the control actuators; the attitude gyro, which limits yaw and roll, is driven by nitrogen.

(3) Once the missiles are launched, the I-TOW, TOW 2, and TOW 2A have extensible probes that provide standoff detonation. The TOW 2A also has a small warhead in the probe that detonates the explosives in a tank's reactive armor. The warhead consists of an aluminum shell, an ogive crush switch, a safety device, electrical wiring, and an explosive filler. Impact and detonation of the conical shape filler concentrate the force of the explosive into a hot jet at approximately 25,000 feet per second, which can penetrate more than 17 inches of RHA.

(4) At the maximum range, the missile slows to one third of its peak velocity. The nose high position of the missile at this range may not produce the best impact angle of the warhead. Basic characteristics of the TOW missile family are shown in Table 5-12. Table 5-13 shows the color codes of the encased TOW missiles.

CHARACTERISTICS	BASIC TOW	I-TOW	TOW 2	TOW 2A	TOW 2B
Missile weight (lb)	41.5	42	47.3	49.9	49.8
Weight in container (lb)	56.3	56.5	61.8	64	64
Prelaunch length (in)	45.8	45.8	45.9	45.9	46
Standoff probe (in)	NA	14.6	17.4	17.4	NA
Max velocity (fps/mps)	981/299	970/296	1079/329	1079/ 329	1010/309
Warhead diameter (in)	5	5	6	5	5(2x)
Explosive filler (lb)	5.4	4.6	6.9	6.9	-
Max range (m)	3000	3750	3750	3750	3750

Table 5-12. Characteristics of the TOW missile family

	HE (BGM)	Training (BTM)
Basic color	Olive drab	Olive drab
Data markings	White	White
Code on aft end	Four brown 2 inch squares 90 apart or 2 inch brown stripes	Same as HE
Code on warhead end	Four yellow 2 inch squares 90 apart or 2 inch yellow stripes	Four blue 2 inch squares 90 apart or 2 inch blue stripes

Table 5-13. Encased missile color codes

(5) The TOW 2 and TOW 2A have an improved propellant in the flight motors, and the guidance links have been hardened with a thermal beacon which improves operations in dust, smoke, and other obscurants. The thermal beacon is compatible with aircraft with the C-NITE system.

(6) The TOW 2B is the newest version of the TOW missile. The TOW 2B entered production in late 1991. The TOW 2B was designed to attack targets from the top. The missile's trajectory places the missile slightly above the target when its two warheads explode downward. Figure 5-29 shows the TOW velocity, time, and range profile.

Figure 5-29. TOW Missile Flight Profile.

b. Approximately 30 different TOW missiles are listed in the conventional ammunition substitutability and interchangeability list published by the U.S. Army Armament, Munitions, and Chemical Command, Rock Island, IL 61299-6000. Your parent command ammunition logistics managers should have a current DODAC listing of TOW missiles.

5-13 AIR-TO-AIR STINGER

Figure 5-30. Air-to-Air Stinger (ATAS) mounted on an OH-58D.

a. The Air-to-air Stinger (ATAS) was designed to destroy enemy aircraft. The ATAS uses infrared (heat sensitive) homing and an overpressure blast with some fragmentation for lethality. The ATAS can accept and function with the unmodified basic Stinger and the Stinger-RMP (Reprogramable Micro Processor). In the (RMP) version, the missile guidance and infrared IR counter-countermeasure (IRCM) functions are reprogrammable by means of a reprogrammable microprocessor in the launcher electronics assembly (LEA). This provides greater countermeasure and background immunity with improved detection characteristics. The RMP Stinger’s seeker dome cover is clear while the basic stinger’s seeker dome cover is cloudy.

b. The Stinger is 59 inches long and weighs 22.4 pounds. The warhead case is titanium with a 2.25-pound explosive filler of HTA-3 (HMX--49 percent, TNT--29 percent, and aluminum flake powder--22 percent). The impact fuze has a self-destruct feature. There are 3 modes of detonation: a low impact switch (LIS) allows warhead to penetrate a soft target before detonation, or a hard target sensor (HTS) allows warhead to detonate upon impact with a hard target or if the missile does not impact and detonate, it automatically explodes 17 seconds after it is launched. Range is predicated on target identification and acquisition and environmental conditions. The demonstrated range capability within favorable conditions is classified.

c. When the Stinger is fired, the launch motor begins missile movement within the launch tube. Before the missile exits the tube, the launch motor is expended and separation sequence is initiated. At a safe distance from the launcher, the launch motor falls from the missile. During this sequence, flight motor ignition takes place. Peak velocity of the Stinger is in excess of Mach 2. Table 5-14 gives the basic characteristics of the Stinger missile.

Figure 5-31. Stinger Missile (Basic) Sections.

	Basic Color	1 Inch Squares	Data Markings	2 1/2 Inch Squares
Shipping and storage container	Forest green		Yellow	Yellow
Missile round	Olive drab	Yellow
Field-handler trainer	Forest green		White	Bronze

Table 5-14. Characteristics of the Stinger missile.

Figure 5-32. The IR portion of the Electromagnetic Spectrum.

d. The missile senses IR radiation emitted from a target by optically focusing the radiation on the surface of an infrared detector cell within the seeker. The cell is cooled by argon gas in the coolant reservoir, i.e., argon gas is very sensitive to IR radiation. When the seeker acquires the IR energy emitted by a target, acquisition signals are produced which inform the pilot of target detection.

(1). The atmosphere is not completely transparent to IR radiation. Certain gases in the atmosphere, primarily carbon dioxide and water vapor, absorb energy in the IR radiation frequency spectrum. The amount of carbon dioxide in the air is fairly constant, and its effect on detection range is constant and need not be considered. Water vapor content varies widely with geographic location and local weather conditions. The amount of humidity in the air proportionately decreases the IR signature of an object. Other particles in the atmosphere such as dust, smoke, fog, and rain, also absorb and scatter IR radiation, and reduce IR acquisition ranges. Radiation types and sources include: Scattered - sun and fire. Emitted - clear sky, terrain, and clouds. Reflected - clouds, terrain, lake surfaces, and snow. NOTE: Clouds and terrain can be either emitting or reflecting sources, depending on the conditions.

(2). Intensity of emitted I-R radiation energy varies according to the size of an area and the source of the radiation. For example, clear sky or clouds cover a large area and emit low intensity radiation. Forest and desert terrain cover large areas and emit medium levels of infrared radiation. The sun represents a large area of high intensity infrared radiation, while an engine exhaust emits a small area of high intensity infrared radiation. These are also referred to as background radiation. NOTE: With the exception of the sun, the engine exhaust or tailpipe of the target is usually the smallest and hottest object in the environment.

(3). Techniques Of discrimination (clouds, haze, terrain reflections). When the target is approaching through clouds, haze, or close to the ground, the pilot must be aware that these and other obscurants can reflect, absorb, transmit and/or emit infrared radiation and a background lock-on could occur.

(a). If you cannot acquire the target due to background noise, continue tracking until the target burns through and acquisition is evident. Keep in mind launch boundaries and be ready to reposition if necessary.

(b). If you still cannot acquire the target, you may launch the missile using the Manual Uncage mode for missile launching. Follow the Manual Uncage procedures IAW TM 55‑1520‑228‑10.