MH-47D Special Operations Aircraft (SOA)
The MH-47D Adverse Weather Cockpit (AWC) Chinook is a twin engine, tandem rotor, heavy assault helicopter that has been specifically modified for long range flights. The CH-47D Chinook has been specially modified to perform the special operations mission and has been tested in combat. It is equipped with weather avoidance/search radar; aerial refueling (A/R) probe for in flight refueling; Personnel Locator System (PLS) for finding downed aircrews; Forward Looking Infrared (FLIR); secure voice communications; Fast Rope Insertion Extraction System (FRIES) for insertion of personnel/equipment and extraction of personnel; defensive armament system consisting of two M-134 machine-guns and one M-60D machine-gun; and internal rescue hoist with a 600 lb. capacity.
A total of 12 MH-47D were introduced beginning in 1985. These were equipped with FLIR, and remain in service, mainly in the so called 'fat cow' role setting up FARP (Forward Arming and Refuelling Points) for other helicopters. In this role up to two aircraft up to 60 meters away can be fuelled, at 454 litres per minute.
The ability to configure the MH-47D with the refueling equipment provides the TF Commander increased mission flexibility by providing a highly mobile forward area fuel source. Many sites are unusable for MH-47D Fat Cow operations. Sites may be rejected due to excessive slope, uneven terrain, or simply that no open area exists as indicated by the map reconnaissance. This method delivers fuel to other aviation assets. The configuration allows each MH-47D to set up a dual Forward Area Refueling Point (FARP) within 10 minutes of arrival at the refueling location. The system has great versatility, allowing the MH-47D not only the ability to refuel other aircraft, but also if the situation dictated, to refuel itself. Refueling is inherently dangerous and requires extensive planning and safety precautions. Operational considerations dictate a need for site security to accompany each Fat Cow sortie. With the Forward Area Refueling Equipment (FARE) set up inside the MH-47D, combined with the support personnel required to conduct the refuel operation, limited space was available for security force personnel. Fat Cow mission elements should have enough security to defend against anticipated threat. Infantry can be used as site security during Fat Cow missions but limit the amount of available fuel for the mission. Inadequate security will degrade the refuel mission of its ability to protect itself long enough to move.
Eleven MH-47Ds remain in service, due to MH-47E acquisition cut-backs. Dramatic reductions in MH-47D operations and maintenance costs and improvements in performance were achieved by upgrading the T55 series engines with the incorporation of a full authority digital electronic control (FADEC) into the engine's existing hydromechanical unit. The Engine Air Particle Separator (EAPS) system installed on the engine inlets did a good job of keeping the engines clean and reduced damage due to foreign object ingestion. However, the EAPS prevented the crew from conducting a proper pre-flight of the engine inlet area.
The MH-47D provides long-range penetration, medium assault helicopter support to special operations forces. Depending on the version, it can be ferried 1,100 to 2,000 nautical miles unrefueled. The internal cabin is 9.14 meters long, 2.29 meters wide and 1.98 meters high. While it can carry two jeeps or a soft-top HMMWV, the HMMWV doors do not have enough clearance to open. The standard crew seating is 33, which can be increased to 44 with extra seats.
During Operation Just Cause, CH-47s conducted H-hour assaults to support other elements who were air-landing SOF to disrupt enemy responses and seize key facilities. During Operation Desert Storm, the CH-47 conducted infiltration and exfiltration of SOF and CSAR of downed pilots.
