Japan Osprey crash caused by cracks in a gear and pilot’s decision to keep flying, Air Force says

WASHINGTON (AP) — A deadly Osprey aircraft crash last November off Japan was caused by cracks in a metal gear and the pilot’s decision to keep flying, instead of heeding multiple warnings that he should land, according to an Air Force investigation released Thursday.

The CV-22B Osprey crash killed eight Air Force Special Operations Command service members and led to a monthslong military-wide grounding of the fleet. It’s among four fatal Osprey crashes in the last two years driving investigations into the Osprey’s safety record. It’s created a split among the services about the future role of the unique aircraft, which can fly like an airplane but land like a helicopter.

For months, the Air Force would only say an unprecedented component failure caused the crash. On Thursday, it identified that a toothed piece called a pinion gear — a critical part of the proprotor gearbox — was to blame. The proprotor gearbox serves as the aircraft’s transmission: Inside each gearbox, five pinion gears spin hard to transmit the engine’s power to turn the Osprey’s masts and rotor blades.

While the Air Force is confident it was the pinion gear that failed, it still doesn’t know why.

But Pentagon leadership in charge of the V-22 Ospreys knew that “total loss of aircraft and crew were possible” should those proprotor gearbox components fail, lead investigator Lt. Gen. Michael Conley told reporters Wednesday in a call ahead of the report’s release. In a rare move, the investigation also faulted that office, saying it did not share safety data that could have educated crews on the severity of the risk.

In an interview with The Associated Press, Conley said he believed it was the pilot’s instinct to complete the military exercise that drove