Sunday, August 19, 2012

Officials with the US Marine Corps have announced their investigation into the fatal crash of a Bell Boeing V-22 Osprey transport plane on April 11 has found pilot error was to blame. The probe found two marines died after the pilots lost control in a tailwind in Morocco.

The accident has triggered attention from Japanese media ahead of a planned deployment there, and officials at a press conference Friday were keen to stress no mechanical or structural defects were found. The pilots had opted for an unplanned 180-degree turn to avoid flying low over obstructions including people and vehicles. This move placed them into a strong tailwind.

This wind tilted the plane forward, but the pilots did not realise and began rolling the engines forward. The Osprey had been flying in helicopter mode, with the rotors pointed skywards; by pointing them forwards, it can be operated as a standard aircraft. Normal flight rules call for the aircraft being level, not tilted, when this switch is made.

These actions moved the center of gravity forward, which pitched the nose further down. Pulling on the flight column was insufficient to correct the problem, and the aircraft flew down into the ground. Two Marines in the back were killed, and both pilots were seriously injured. The investigation suggested leaving the aircraft in helicopter mode could have prevented the accident.

The wounded pilots are still recovering, and Marine Corps Aviation’s deputy commandant Lt. Gen. Robert Schmidle said that when they are well enough they will go before a panel to determine if they are fit to fly. He says their actions will be scrutinised then. Schmidle also said the model’s flight manual will be updated and training given to pilots in light of the crash.

“It’s an extraordinarily complex set of circumstances that caused this to happen”, he told reporters Friday. He called the plane a “solid, safe” model.