What happened
On 22 August 2023, a CV-22B Osprey, tail number 17-0077, crashed at the Melrose Air Force Range in New Mexico. The aircraft, assigned to the 20th Special Operations Squadron of the 27th Special Operations Wing, was conducting aerial gunnery training and supporting a joint terminal attack controller (JTAC) team.
Following the completion of training maneuvers, the crew raised the landing gear and began transitioning from a hover into forward flight. During this phase, a flight engineer moved to take their seat; however, excess slack in the night vision goggle (NVG) battery pack cable caused the cable to snag on the right engine control lever (ECL). The movement pulled the lever from the FLY position to the OFF position, resulting in an immediate shutdown of the right engine. Lacking sufficient power and altitude to maintain flight, the aircraft descended at a rate exceeding 1,200 feet per minute, impacting the ground with its landing gear retracted. The aircraft slid approximately 360 feet on its belly. One crew member sustained a head injury during the impact but was treated at a local hospital and released.
The investigation
The Accident Investigation Board (AIB) examined the mechanical state of the aircraft, the environmental conditions, and the actions of the aircrew. Investigators analyzed the configuration of the flight engineer's helmet and the management of the engine control levers. The board also reviewed weather data, noting that the aircraft was operating with a tailwind component that exceeded prescribed limits for the specific flight phase.
Findings
- Unintentional engine shutdown: The primary cause was the flight engineer unknowingly moving the right ECL to the OFF position via a snagged NVG battery cable.
- Failure to guard controls: The aircraft commander did not adequately guard the engine control levers during the transition.
- Environmental factors: The crew failed to perform an accurate real-time risk assessment regarding wind conditions, as the actual tailwind was significantly higher than the crew had estimated.
- Procedural gaps: There was a lack of standardized guidance for securing excess cables on helmets and no established procedure for guarding critical flight controls during seat changes in the cockpit.