AGM-114 Hellfire Employment
There are different techniques for tactical employment of the Hellfire missile on the battlefield. These techniques are ultimately driven by the two engagement methods by which the missile can be controlled to the target: autonomous and remote. An autonomous engagement requires the aircraft launching the missile to guide it all the way to the target after the missile is away. In this method, a single aircraft and its crew will locate, identify, fire, and guide the missile until destruction of the target in the same way an M2/M3 Bradley crew employs its TOW missiles. In contrast, a remote engagement requires an aircraft to serve as a launch platform, providing a missile for another aircraft or a ground observer, designating with a laser, to guide the missile to its intended target. A ground designation station such as an FO or Combat Observation Lasing Team (COLT) accomplishes this with lasing devices like the G/VLLD or MULE.
With a remote engagement, the air crew is responsible only for delivering the missile toward the general location of the target, but is no longer responsible for its guidance once it leaves the external launch rails. This allows remote engagements to provide one distinct advantage over autonomous engagements. Using this technique, the launch aircraft is often able to remain masked behind terrain, greatly reducing its visible launch signature while delivering missiles toward the target array, thereby increasing aircraft survivability - a force protection consideration. Remote engagements, however, require a great deal more coordination and planning between the "shooter" and the "observer."
In addition to the two methods of engagement, there are four modes of delivery that aircrews can utilize when firing the Hellfire missile. These delivery modes are driven by three factors: distance to the target, the weather (primarily visibility and cloud ceiling height), and terrain conditions under which the missile will be fired. When a Hellfire missile flies through obscuration (fog, clouds, smoke) or if the designator fails to lase the target properly until impact, the missile loses laser lock and will be lost for good. Only one model of Hellfire missile, the AGM-114K, has a built-in system to assist in the reacquisition of the target after laser lock-on is lost. The AGM-114L, when fielded, will provide a true fire-and-forget capability.
The first delivery mode is known as the Lock-on Before Launch (LOBL) technique. In this mode, the missile laser seeker acquires and locks-on to the coded laser energy reflected from the target prior to launch. The advantage to using this particular delivery mode is that the air crew is assured that the missile has already positively locked on to the target prior to launch from the aircraft, thereby reducing the possibility of a lost or uncontrolled missile. The disadvantages of a LOBL delivery revolve around the trajectory of the Hellfire missile. To compensate for a low cloud ceiling, an aircraft may need to expose itself to threat weapons ranges in order to ensure a successful engagement.
One method to reduce the maximum altitude of the Hellfire's flight trajectory is to select the Lock-on After Launch -Direct (LOAL-DIR) delivery mode. This delivery mode results in the lowest of all trajectories during missile flight because it is employed using a laser designation delay. Overall, depending on the length of laser delay time, the maximum altitude reached during the flight trajectory is much lower; a distinct advantage over all other delivery modes. The downside to this method, however, is that air crew is not assured of positive lock-on prior to launch.
The last two delivery modes are unique in that they allow the launch aircraft to remain masked behind terrain to reduce its firing signature and increase aircraft survivability. These delivery modes are known as Lock-on After Launch - High (LOAL-HI) and Lock-on After Launch -Low (LOAL-LO). The first mode, LOAL-HI, allows the missile to clear a 1,000 ft. high terrain feature to front of the aircraft, provided the aircraft remains a minimum of 1500 meters away from that terrain feature. This technique is most effective in a remote engagement. The major disadvantage of employing the LOAL-HI method, however, is that the missile flies the highest trajectory of all delivery modes and is most susceptible to a break in missile lock due to penetration of low-lying clouds. Using the last delivery mode, LOAL-LO, will help to reduce the maximum altitude of the Hellfire trajectory somewhat, but will also limit the size of the terrain mask utilized by the aircraft for survivability.
Under most battle circumstances, the Hellfire is a restricted resource. Ammunition supply rates help commanders determine needs and plan allocations when inadequate amounts of missiles are available. The required supply rate (RSR) and the controlled supply rate (CSR) are the key statistics that drive the planning for use and resupply of Hellfires. The RSR is the amount of missiles a maneuver commander estimates he will need to sustain tactical operations without restrictions for a specific mission over a given period. The CSR is the amount of ammunition that the corps allocates to each unit based on the availability of ammunition, class V storage facilities, and transportation assets over a specific period. Both RSR and CSR are expressed in rounds per weapon system per day.
In Exercise Desert Victory in February 1999, the PK was 25 percent for stationary, dug-in targets and 35 percent for moving targets. A PK of 25 percent would require four times as much ammunition to destroy a target as a PK of 100 percent. A PK of 35 percent would require 2.9 times as much ammunition to destroy the target. In Exercise Urgent Victory, the PK was 70 percent for all targets, so fewer missiles were needed to accomplish the mission than in Desert Victory. PK may vary among units. Regardless of the PK, the important factor is the analysis, which develops the ammunition requirement.
If, for example, a regiment must destroy 3,500 targets over a 7-day period, it must destroy 500 targets each day. To destroy 500 targets with a PK of 25 percent, the regiment needs 2,000 Hellfires a day. The regiment expects to use 96 AH-64s; 2,000 divided by 96 equals 20.8. So the RSR is 21 Hellfires per aircraft per day. The S3 assessed the following weapons loads on the aircraft per troop: 5 AH-64s with 12 Hellfires, 0 rockets, 660 30-millimeter rounds, 1 auxiliary tank (60 Hellfires total for the troop); and 3 AH-64s with 8 Hellfires, 19 rockets, 660 30-millimeter rounds, 1 auxiliary tank (24 Hellfires total). Some units installed a Robertson fuel tank on their helicopters. The "Roby" tank provides the helicopter about 1 hour of additional flight time. When used, the "Roby" tank replaces the external auxiliary tank. This limits the 30-millimeter cannon to 90 rounds but allows all four wing stores to carry ammunition, providing space for an additional missile launcher or rocket launcher.
The first shots of Operation Desert Storm occurred on 17 January 1991 when eight APACHE helicopters used HELLFIRE missiles and HYDRA-70 rockets to destroy two Iraqi early-warning ground control radar sites. However, this was not the first time that HELLFIRE missiles had been fired in combat. Over a year before, US Army troops successfully used HELLFIRE against seven targets during Operation Just Cause in Panama. One of the Army's premier antitank weapons systems, an estimated 2,900 to 4,000 HELLFIRE missiles were fired during Operation Desert Storm, 80 to 90 percent of which were judged to have hit their target. The system proved itself to be very effective against a variety of moving and stationary targets, including tanks (APACHE helicopters destroyed over 50 Iraqi tanks in one battle alone), other armored vehicles, radar sites, bunkers, and other fortified positions. HELLFIRE missiles were also unintentionally involved in several "friendly fire" incidents during Operation Desert Storm. Of the 148 Americans killed in combat in SWA, 35 died as a result of fratricide. Because the Hellfire could operate at longer ranges than APACHE pilots can identify targets, pilots were unable at times to distinguish between Iraqi and coalition forces thereby increasing their chances of inadvertently causing the death of a fellow soldier.
On 27 February 1991, during an attack on the Al-Hammar causeway bridge, APACHE helicopter pilots from Fort Rucker, Alabama, watched in amazement as one HELLFIRE missile "...left its launch rail and streaked up into the afternoon sky until it disappeared.... Two other missiles left the launch rails in a crazy spiral and plowed into the sand a few hundred yards away." This seemingly erratic behavior was not the result of a problem with the missiles themselves. It was indicative of a backscatter situation. Backscatter is the term given to laser or light energy refracted for particulate matter in the air. The problem was intensified in SWA by the vast areas covered by fine sands and the need for the helicopters to hover at relatively low altitudes while locating and engaging targets. The HELLFIRE Project Office correctly diagnosed that the missiles were not behaving erratically after firing but were, in fact, following the laser beam they detected. Although all APACHE helicopter pilots had been taught to be alert for possible backscatter situations, the project office sent a contractor representative from Rockwell International Corporation to SWA to reemphasize backscatter countermeasures that would improve pilot and missile performance.
Also during ODS, there were a series of inadvertent launches experienced with the HELLFIRE missile system. The project office initiated a program to determine the exact cause of these unplanned launches as well as a modification program on the forward wiring harness of the electronic control systems processor, a major portion of the HELLFIRE launcher.
The HELLFIRE system, the first and last weapon fired during the war, was very effective during Operation Desert Storm. However, some problems with the system's readiness and use were encountered in conjunction with the Persian Gulf conflict. Between 9 November 1990 and 15 January 1991, the HELLFIRE Project Office offered equipment checkout assistance to units alerted for deployment to SWA. Findings from the assistance visits indicated serious readiness problems with the HELLFIRE/APACHE subsystem. Of the 54 aircraft checked by pre-deployment assistance technical represent- atives, 18 (or one- third of those checked) were found to have reduced missile launch capability; 10 launchers were found to be unserviceable. To address this problem, the project office dispatched a contractor technical representative contact team to SWA from December 1990 through January 1991. A total of 114 aircraft were checked out, with 41 HELLFIRE system defects and 14 aircraft electrical problems discovered. The team made the necessary adjustments and repairs to restore the units to a high readiness posture.
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