AH-1T, AH-1W, and AH-1Z used variants of the M97 series. The subsystem used on the AH-1T and AH-1W has a designation in the USAF's Aeronautical and Support Equipment Type Designation System (ASETDS), A/A49E-7. The turret in the system is also designated under the ASETDS system, as the GTU-1/A. How this system differs from its US Army counterparts is unknown. An amendment to the official Military Specification, MIL-F-85668(AS), put out by the United States Naval Air Systems Command on 15 November 1995, actually listed the "A/A49E-7(V4)" as inactive pending a new design, and listed the system as relevant only to the "AH-1T (TOW)." XM120 (Emerson TAT-140) A competing universal turret design to the M97 put forward by Emerson Electric, the XM120 could be fitted with a number of weapons including the M60C 7.62×51mm machine gun, M134 Minigun, M197 20 mm three barreled cannon, XM188 30 mm three barreled cannon, and was in fact tested with the XM140 30 mm cannon. AH-56 Cheyenne The Lockheed AH-56 Cheyenne got no further than operational testing of the ten prototypes before the program was cancelled. XM51 A nose turret with one M129 40 mm grenade launcher with 300 rounds. In light of the cancellation of the AH-56 was proposed as a replacement for the M5 system on the UH-1 helicopter. Designed to be interchangeable with the XM53. XM52 Belly turret with a single XM140 30 mm cannon. Use on other helicopters was also debated. XM53 A nose turret with one 7.62×51mm XM196 machine gun. Also said to be suitable for the UH-1 series of helicopters. Designed to be interchangeable with the XM51. AH-64 Apache M139 and Area Weapon Subsystem The only type classified subsystem for the Boeing AH-64 Apache series, the M139 is composed of the "Aerial Rocket Control System" which gives the aircraft the ability to fire members of the Hydra 70/Mk 66 2.75 in/70 mm rocket family, a dispenser interface controlling the M130 chaff/flare dispenser (also used on the AH-1 helicopter), and the Area Weapon Subsystem. The Area Weapon Subsystem is made up of a single M230 30 mm chain gun, turret and assembly, ammunition feed, and other electronic components for the functioning of the system. The unit is capable of 100 degrees of motion in azimuth left or right, 11 degrees of elevation and 60 degrees of depression, and feeds from an ammunition magazine with 1,200 rounds. RAH-66 Comanche Turreted Gun System