Weak spots in metal may have led to fatal Osprey crash off Japan, documents obtained by AP reveal

WASHINGTON (AP) — A gear crack that led to a fatal crash of a V-22 Osprey last year may have been started by weak spots in a metal used to manufacture that part, according to documents obtained by The Associated Press.

The November crash killed eight Air Force Special Operations Command service members. It was the second time in less than two years that a catastrophic failure of a part of the Osprey’s proprotor gearbox, which serves as its transmission, caused a fatal accident. In June of 2022, five Marines were killed when a different part of the proprotor gearbox system failed.

The crashes have led to an aggressive effort by the V-22 program office and manufacturer Bell Flight to find fixes for the critical system, which has had some components wear down earlier than the military expected. While investigators still don’t know for certain what caused either crash, this latest finding might hold some clues.

There’s no other aircraft like the Osprey in the fleet. It can speed to a target like an airplane then rotate its engines to land like a helicopter. Program leaders have pointed out that the Osprey has been vital in special operations and combat missions and has flown hundreds of thousands of hours successfully.

But the aircraft also has a troubled crash history, and the proprotor gearbox has been a persistent problem.

Data gathered by The Associated Press through the Freedom of Information Act shows 609 proprotor gearboxes have been removed for repair in the past 10 years. Over the last five years, the Marine Corps, Navy and Air Force have reported 60 incidents involving the proprotor gearbox.

Last week the Air Force identified cracking in a pinion gear, a part that’s about the size of a large jar lid, as one of two