History of Flight
On January 16, 2012, about 1045 Afghanistan time (0615 UTC), a Bell 214ST helicopter, registration N5748M, crashed 7 miles south of Camp Bastion in Helmand province, Afghanistan. The helicopter was operated by AAR Airlift Group under contract to the Department of Defense Air Mobility Command. The flight was conducted under 14 CFR Part 135. Visual meteorological conditions prevailed. The three crewmembers, who were US citizens, died as a result of their injuries. The helicopter was destroyed by impact forces and postcrash fire. No hostilities were reported in the area at the time.
The accident helicopter was flying between forward operating bases with another Bell 214 (N391AL) to transport military personnel. Both departed Shindand Air Base about 0901, stopped at Camp Farah for refueling and passenger changes, then departed for Camp Bastion about 0934. They arrived at Camp Bastion about 1031, where passengers disembarked. Slingshot 72 (the accident helicopter) took no new passengers; Slingshot 71 took four. After walk-around inspections, both helicopters departed Camp Bastion about 1040 for Shindand on a heading of 190°, climbing to between 800 and 1,000 feet. Slingshot 72 was lead, about ¼ to ½ mile ahead and slightly above and to the right.
Slingshot 71's crew observed Slingshot 72 enter a sharp right bank (estimated 70°–80°), then begin to come apart. The tailboom separated and folded, and the helicopter pitched down about 75°–80°, impacted the ground, and burst into flames. No distress calls were made. Slingshot 71 circled the wreckage, coordinated with Camp Bastion tower for rescue, and later landed uneventfully.
The NTSB accepted full delegation of the investigation from Afghanistan on January 18, 2012. The wreckage was sent to the United States for examination.
Personnel Information
The three crewmembers were the pilot-in-command (PIC), second-in-command (SIC), and crew chief. The PIC, age 48, held an airline transport pilot certificate for BH-214ST and BK 117 helicopters, with about 7,250 total hours (480 in type). The SIC, age 51, also held an airline transport pilot certificate for BH-214ST, with about 4,170 total hours (120 in type). Both had current medical certificates and no prior enforcement actions. The accident occurred during the sixth flight of the day, about 4 hours into duty.
Aircraft Information
The accident helicopter, serial number 28102, was built in 1984 and had accumulated 12,346 total flight hours as of January 15, 2012. It was a Bell 214ST with a two-bladed semi-rigid main rotor, two-bladed tail rotor, two General Electric CT7-2A engines, and hydraulically assisted flight controls. It was equipped with a portable Garmin GPS that recorded the final flights.
Meteorological Information
At the time of departure from Camp Bastion, sky condition was clear, visibility unrestricted, and wind variable at 6 knots.
Wreckage and Impact Information
The accident site consisted of a primary impact area and a debris field measuring about 1,575 feet north-south by 656 feet east-west. The main fuselage was fully consumed by postcrash fire. The forward tailboom section was separated and found about 49 feet north of the impact area; the aft tailboom section (with vertical stabilizer and tail rotor) was found about 279 feet north. A main rotor blade was found about 426 feet southwest. Examination revealed that only the right collective lever arm was recovered; the left was missing. Impact marks on the idler link and swashplate support assembly were consistent with overtravel of the collective sleeve upward. Damage to the main rotor mast showed evidence consistent with mast bumping. Tail rotor drive and control continuity could not be confirmed forward of the aft tailboom due to breaks and fire damage, but no evidence indicated loss of tail rotor drive or control before separation. Both engines showed evidence of power at impact. Hydraulic actuators showed no abnormal operation.
Maintenance records indicated the collective torque shaft support bracket was replaced the day before the accident; installation appeared proper, and a functional check flight was completed with no defects.
Additional Information
DOD conducted oversight of AAR Airlift Group via evaluators in Afghanistan. Cockpit evaluations and a biennial survey from October 2011 showed satisfactory operations. The company's Part 135 certificate was held at the Orlando FSDO, and the principal and assistant operations inspectors reported no significant concerns.
Flight Recorders
The helicopter was equipped with a cockpit voice recorder (CVR), but chip-level recovery revealed all four channels contained unusable audio, consistent with the CVR being inoperative or misconfigured.
Medical and Pathological Information
Postaccident toxicology tests were not performed on the crewmembers.
Tests and Research
Bell Helicopter performed math model simulations of a collective flight control system failure. The results indicated that a reduction in main rotor collective pitch would cause a severe right roll and nose-down pitch attitude, and that, with or without pilot aft cyclic input, the main rotor blades would deflect downward and nearly contact the tailboom.