The Pentagon has grounded all of its V-22 Ospreys following a deadly crash in Japan that killed eight people. This isn’t the first time this has happened to the troubled aircraft, which has a long history of malfunctions, crashes, and death.
This most recent crash happened on November 29 during a training exercise in the waters off of Yakushima Island. A CV-22B using the call sign “Gundam 22” was flying eight U.S. service members between locations in the South China Sea when something went wrong and it crashed. The Pentagon has identified the service members aboard, but has only recovered six of the bodies.
The Japanese Defense Forces, which has 14 of its own Ospreys, grounded the vehicles after the crash and said that the U.S. wasn’t giving it enough information about what might have gone wrong. On Wednesday night, the Air Force, Marines, and Navy followed the JDF in grounding their Ospreys.
“Preliminary investigation information indicates a potential materiel failure caused the mishap, but the underlying cause of the failure is unknown at this time,” Air Force Special Operations Command said in a statement. “The standdown will provide time and space for a thorough investigation to determine causal factors and recommendations to ensure the Air Force CV-22 fleet returns to flight operations.”
A statement from the Naval Air Systems Command also said that a materiel issue was to blame. “While the mishap remains under investigation, we are implementing additional risk mitigation controls to ensure the safety of our service members,” the statement said, but didn’t elaborate on what those mitigation controls might be.
The V-22 has been here before. It’s common for the military to ground its fliers after an accident or series of accidents. The Army grounded all of its aviation units in April following multiple helicopter crashes. But this has happened multiple times to the V-22 since its deployment in 2007. The Pentagon last grounded V-22s in February.
The V-22 Osprey is a tiltrotor aircraft. It can take off and land like a helicopter, then its rotor tilts at a 90 degree angle and it can fly like a plane. It’s meant to provide the military with a vehicle that provides the best of both worlds. It can take off and land without a traditional runway, and all the logistical support a runway entails, while maintaining the cruising speed of a traditional aircraft.
The two main issues are dust and the clutch. When an Osprey lands in dirt, it kicks up a lot of debris into the air. That dust circulates through the engines which run so hot that, sometimes, the dust is turned into glass. The glass sticks to the engines and can cause mechanical failure. It’s so bad that there are policies in place that advise pilots to evacuate dust clouds as quickly as possible. The military has designed multiple engine filters to combat the issue, but it persists.
The other problem is what’s called a hard clutch. “A Hard Clutch Engagement event occurs when the clutch, driven by the engine, releases from the rotor system and suddenly reengages, sending an impulse through the drive train, potentially causing damage,” a Marine Corps statement on the issue said in February 2023, the last time it grounded its V-22s.
The Osprey crashes a lot, but not all the incidents are fatal. A Marine was injured in October in a crash. Three Marines died in an Osprey crash in August in Australia. In October 2022, an Osprey caught fire in California. In June 2022, five Marines died in an Osprey crash. An investigation later blamed the hard clutch issue. The list of fatal and non-fatal incidents involving the Osprey is long and it might be months before we know what exactly happened off the coast of Japan.