The pilots flying a V-22 Osprey failed to recognize the effect of a strong tailwind on the tiltrotor aircraft and were unable to recover in time to prevent it from plunging into the ground during an April crash in Morocco that killed two crew members, the Marine Corps said Friday.
Marine Lt. Gen. Robert Schmidle, the deputy commandant for aviation who briefed reporters on the results of the investigation, said that to avoid structures and people in the area, the pilots rotated the V-22 to turn away from the headwind that is preferred during takeoffs, opting to fly with a tailwind.
The V-22 was unable to cope with the tailwind as it transitioned from helicopter mode into airplane mode, and the pilots had little stick space to pull the aircraft up, Schmidle said. He added that the pilots could have avoided the crash if they kept the aircraft in helicopter mode longer, to gain enough speed to support the flight transition. Wind gusts were ranging that day from 15 to 27 knots, he added.
The flight status of the pilots is under review, he said.
The results of the accident came as the Pentagon seeks to persuade the Japanese government that the V-22s are safe to operate. The Marines deployed 12 V-22 in Iwakuni, Japan on July 23, and they are eventually to be stationed at Marine Corps Air Base Futenma, which lies in a densely populated area of Okinawa.
The potential presence of the V-22s on the base has alarmed local residents concerned about their safety. The Japanese government has insisted on reviewing the results of investigations into the Morocco accident and a subsequent, non-fatal one in Florida involving an Air Force version of the aircraft before green lighting V-22 operations on Okinawa.
“The one thing that did come through (the investigation) loud and clear is there was nothing wrong mechanical with the airplane,” Schmidle said.
Pentagon officials have said the Ospreys, built by a partnership between Boeing [BA] and Textron [TXT] unit Bell Helicopter, have come a long way since being plagued by development problems in the 1990s that produced several fatal accidents and caused the program to be put on hold.
The V-22s are slated to replace legacy CH-46 Sea Knight helicopters in Japan. Marine Commandant Gen. James Amos said Thursday that a Japanese evaluation team in Washington had been briefed on the Morocco crash inquiry ahead of the public release.
“Historical data gathered from the past 10 years of flying proves that the Osprey is one of the safest aircraft flying in the U.S. inventory,” Amos said in a statement. “Having surpassed 100,000 flight hours last year and over 13 highly successful combat deployments to both Iraq and Afghanistan, the airplane has proven its mettle in some of the most demanding environmental conditions imaginable–including having been shot at and hit on several occasions during combat.“
The Pentagon wants the V-22s in Japan because of their enhanced capabilities suitable for the Asia-Pacific theater. V-22s are able to fly at higher altitudes, faster speeds and longer ranges and are a significant upgrade over the CH-46s for responding to military contingencies, disasters and for humanitarian operations.
The deployment was the subject of a meeting in Washington earlier this month between Defense Secretary Leon Panetta and his Japanese counterpart, Satoshi Morimoto. Morimoto, who flew on a V-22 during the visit, reiterated that his government wanted to assess the recent accidents before signing off on Okinawa operations.
“The United States will give us the report of the investigations with regard to what happened in Florida and Morocco as soon as possible, and until we confirm the safety of it the United States will refrain from flying the Osprey,“ Morimoto said through a translator.