The 11 April, 2012, crash of a Bell-Boeing MV-22B Osprey tilt-rotor in Morocco belonging to the US Marine Corps's VMM-261 squadron was not due to a mechanical failure or and other safety defect.
Instead, the aircraft, which was participating in an exercise called African Lion alongside Moroccan forces, crashed due to pilot error. Two marines were killed in the accident, while the two USMC pilots flying the aircraft were severely injured.
Lt Gen Robert Schmidle Jr, the Marines' deputy commandant for aviation, says the aircraft took-off vertically with the wind coming from directly head-on relative to the aircraft. The aircraft climbed vertically to about two dozen feet into the air when the pilots decided to execute a pedal-turn to the right in order to avoid overflying some Marines on the ground.
As the pilots executed that turn, the wind was now coming from behind the aircraft. Moreover, the pilots had started to use a thumb-wheel on the MV-22's throttle/collective to rotate the aircraft's engine nacelles forward. That, Schmidle says, caused the Osprey's center of gravity to shift forward.
In the configuration, the pilot's control column did not have enough control authority to move the nose up. The aircraft subsequently flew into the ground, Schmidle says. An investigation found that the aircraft may not have crashed had the pilots kept the aircraft in helicopter mode.
Schmidle says that pilots were flying in a condition where the MV-22 Naval Air Training and Operating Procedures Standardization (NATOPS) manual advises caution-but there is no explicit prohibition on flying in that part of the envelop. But the manual could be clearer and it will be amended, he adds.
The MV-22 pilot community will also receive enhanced training and academics to better learn to recognize and avoid a similar situation if they should encounter the same conditions, the general says.
The MV-22 is a "solid, safe" aircraft, Schmidle emphasizes.