WASHINGTON (news agencies) — 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 media.
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 media 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 factors that caused the crash off Japan. The Air Force also faulted the pilot and crew, because the Osprey sent six warnings during their flight that the proprotor gearbox was in trouble.
But additional crash report documents obtained by the news agencies show this is not the first time this metal has failed in Osprey proprotor gearbox components, although it was the first time it failed in this specific gear. There have been seven previous cracking incidents in related gears that were likely caused by the same metal weakness, investigators reported.
It’s not clear if that information had previously been shared with the services, which could have led them to take a much more restrictive approach to how pilots were instructed to respond to any proprotor gearbox warnings.
In a rare move, as part of the accident report released publicly last week, the Air Force faulted the V-22’s program office for not sharing data that could have better informed crews of the severity of the risk.
