Tuesday, February 1, 2011
Disputes Arise from Afghanistan CV-22 Crash Probe
Don Harvel, an airline pilot who as a Texas Air National Guard brigadier general led the eight-member Aircraft Investigation Board, concluded that one of 10 contributing factors was power loss in both the Osprey’s Rolls-Royce AE 1107C-Liberty engines. But AFSOC’s vice commander, Maj. Gen. Kurt Cichowski, declared in an addendum to the investigation that “the preponderance of evidence in this report does not support a determination of engine power loss as a substantially contributing factor.”
Harvel, who retired from the Air Force as scheduled three months before AFSOC released his report Dec. 16, told Rotor & Wing the disagreement couldn’t be resolved because the Osprey’s flight incident recorder (FIR), which records engine data and instrument readings, was never recovered, though searchers retrieved a variety of classified gear at the crash site.
“Nobody in operations knew the flight incident recorder existed, and very few maintenance personnel knew it existed,” Harvel said, because the fact that the CV-22B carried a FIR was somehow omitted when the Air Force Osprey’s manual was “translated” from the Marine Corps MV-22B manual. “The only ones who knew it was on the airplane were the ones that actually had to test and maintain it,” Harvel said of the FIR, and none of them took part in searching the wreckage. “I have a feeling it’s still out there,” he added.
Four hours after the crash, which occurred at 12:39 a.m. local time April 9, two Air Force A-10 “Warthog” aircraft dropped four 500-lb bombs on the wreckage, as an Army commander recommended, so it wouldn’t have to be guarded.
Even so, an Army unit from a nearby forward operating base later recovered the Osprey’s left engine and other parts, Harvel said. Harvel and other board members were flown over the site in a helicopter a month and a half later but were told they couldn’t land because of a risk insurgents had planted explosives there. Speaking after he left the Air Force, Harvel said he believed the FIR—built to withstand a crash—might still be intact but may have been buried by the A-10 bombing or taken by scavengers.
Brig. Gen. OG Mannon, who became vice commander of AFSOC last fall after Cichowski was promoted to lieutenant general and assumed other duties, told reporters in December that no search for the FIR had been made after the wreckage was bombed and, absent new evidence, none would be undertaken. Harvel signed the report, making the investigation complete, Mannon said.
The crash was the first involving the Air Force version of the Osprey, a tiltrotor transport primarily flown by the Marines that can swivel two wingtip rotors up to take off and land like a helicopter and forward to fly like an airplane. The CV-22B that crashed, the lead among three carrying Army Rangers on a night raid against an insurgent target, touched down a quarter mile short of its intended landing zone, a desolate area five kilometers east/southeast of the village of Qalat, at about 80 knots.
The Osprey hit with its landing gear down and rotors up at more than 80 degrees, or nearly the 90 degrees used to land like a helicopter. It raced across the flat, sandy earth in what some aboard thought was a fast roll-on landing, then its front wheels bounced, struck the ground and collapsed. The nose plowed into the soft soil, then hit a two-foot-deep gully, flipping the aircraft tail-over-nose onto its back, crushing the cockpit and slamming the fuselage into the ground upside down.
Killed in the cockpit were two Air Force 8th Special Operations Squadron crew members: pilot Maj. Randell D. Voas, 43, who was in the left seat, and Senior Master Sgt. James B. Lackey, 45, a flight engineer seated in a jump seat between Voas and the copilot. Cpl. Michael D. Jankiewicz, 23, of the 3rd Battalion, 75th Ranger Regiment, and an Afghan woman interpreter, whose name was withheld, died in the cabin. The copilot, thrown from the aircraft in his seat, survived. Also surviving were another Air Force flight engineer, 13 Rangers, and a male Afghan interpreter, all of whom had been kneeling in the cabin, wearing safety harnesses attached to the floor. Some were seriously injured.
Potential causes ruled out by the investigation included enemy fire, a “brownout” landing that disoriented the pilot or vortex ring state, the cause of the worst Osprey crash in history, in which 19 Marines died at Marana, Ariz. on April 8, 2000, during an operational test of the V-22.
Harvel and Cichowski agreed on nine contributing factors: inadequate weather planning, a poorly executed low visibility approach, an unexpected 17-knot tailwind, a “challenging visual environment” on a moonless night, crew “task saturation,” the copilot becoming distracted and spending too much time looking outside the aircraft instead of at instruments, the crew pressing to achieve their first combat mission in Afghanistan, and an “unanticipated high rate of descent.”
Harvel concluded that while Voas flew his approach too fast and was surprised by the tailwind, the highly skilled pilot most likely was attempting an emergency roll-on landing because he lacked enough engine power to fly around or land in helicopter mode, as opposed to accidentally flying the Osprey into the ground.
If so, the CV-22B must have lost power in both engines, Harvel said, as a driveshaft connects the rotors and a V-22 can land like a helicopter on one of its 6,150 shaft horsepower engines. The engines might have lost power due to compressor stalls caused by the right quartering tailwind combined with the high pressure altitude where the crash occurred—5,226 feet above sea level—or by mechanical failure, Harvel said.
In concluding that no power loss occurred, Cichowski cited a lack of any crew discussions or recorded warnings before the Osprey crashed as well as a Rolls-Royce study of the recovered left engine and analysis by the Naval Air Systems Command (NAVAIR), which runs the Osprey program. “The probability of an engine failure, less than two seconds prior to impact, was assessed as being highly remote,” Cichowski wrote. Rolls-Royce concluded that “the left engine was operating at time of impact,” he added, and NAVAIR’s analysis “indicated” that “a single engine failure was unlikely.” —By Richard Whittle
The complete report, including witness statements, is available at www.afsoc.af.mil/accidentinvestigationboard/index.asp