The Marine Corps says that three Okinawa V-22 Ospreys that diverted from scheduled flight paths last week due to "caution indications" in the cockpit did not appear to suffer from a clutch issue that has plagued the service's fleet and caused at least one fatal crash.
"Currently, there are no indications that these events resulted from an MV-22 hard clutch engagement (HCE) malfunction. In each of these events, the aircraft sensors and monitoring systems performed as designed," Maj. Rob Martins, a spokesperson for the Okinawa-based 1st Marine Aircraft Wing, said in an email Monday night.
The clutch malfunction shreds components that power the Osprey's twin rotors, and appears to be a risk for both the Marine Corps and Air Force fleets. Last year, a crash caused by a hard clutch engagement killed five Marines in an Osprey incident near El Centro, California.
The cause of the warnings in the Osprey cockpits was not disclosed by the service.
The Marine Corps has said that it has significantly reduced the risk of hard clutch engagements following the crash of the "Swift 11" Osprey last year, though some families of the Marines who died in the incident remain skeptical.
Prior to the Osprey diversions last week, three Marines also died in late August after their Osprey went down during a routine multinational training event near the Northern Territory of Australia.
An investigation into the cause of that deadly Osprey incident in Australia is still ongoing.
Military.com reported last week that two Okinawa Ospreys made forced landings on the southern islands of Japan within two hours of each other. Two days later, a third Osprey diverted to Oita Airport on the southwestern part of the mainland, marking three total in two days.
"When a caution light appeared in each cockpit, the pilots and aircrew complied with safety procedures and diverted their aircraft, landing safely so each aircraft could be assessed," Martins said.
The first two Ospreys were diverted on Sept. 14 and returned to Marine Corps Air Station Futenma on Okinawa within the following few days "after completing necessary troubleshooting and maintenance actions," Martins said.
The third Osprey that diverted landed at Oita at around 4:35 p.m. local time on Sept. 16. The pilots and aircrew followed proper landing procedures and diverted "out of an abundance of caution." The aircraft was being examined Monday and was also set to return to Futenma when it was deemed safe to fly.
"We appreciate the support from our local communities and host-nation partners during the brief time needed at each airfield to ensure the safe return flights of each aircraft back to Futenma Air Station," Martins said. "We operate all of our aircraft in accordance with established standards and procedures, and remain fully committed to safety."
The past month has proved to be a perilous time for Marine Corps aviation.
On Monday, the Marine Corps finally found what it believed was the debris of a downed F-35B Lightning II -- a roughly $80 million fighter jet -- more than a day after it went missing over South Carolina. The pilot safely ejected from the jet on Sunday before it disappeared.
A F/A-18D Hornet crashed in southern California on Aug. 24, claiming the life of its singular pilot.
In total, the Marine Corps has experienced two deadly aviation crashes, one briefly missing jet and three known forced Osprey landings in about 24 days.
The top Marine Corps leader, Gen. Eric Smith, who is acting as commandant but has yet to be confirmed by the Senate, on Monday ordered a two-day safety stand-down for aviation units this week, where all operations are paused and commanders will discuss safety fundamentals with their troops.
-- Drew F. Lawrence can be reached at firstname.lastname@example.org. Follow him on Twitter @df_lawrence.