For security reasons, the Pentagon has temporarily suspended the operations of its global fleet of V-22 Osprey tiltrotors again in recent hours, after some metal components had probably played a decisive role in an emergency landing at Cannon Air Force Base in New Mexico, on November 20. There are too many similarities, military authorities inform, with the causes that led to the tragic accident that occurred in Japan in November 2023 on the island of Yakushima, which caused the death of eight soldiers of the American Air Force Special Operations Command.

But there have been several safety-related cases reported in particular in the last five years, and highlighted by an in-depth investigation: at the root there would be the fact that some metal parts would be wearing out faster than expected. For starters. The results of the investigation were sent to Defense Secretary Lloyd Austin, along with a request to ground the fleet of V-22 Ospreys until solutions are implemented to address the safety and design issues identified by the investigation.

A grounding that was also recommended last week by Vice Admiral Carl Chebi, head of Naval Air Systems Command, which manages the Osprey program for the US Army.

In the Japan accident, inclusions -or weak points- in the metal used for critical gears inside the Osprey's transmission led to the gears failing in flight and causing a catastrophic failure. The crew did not realize the severity of the failure at the time and did not land immediately.

The metal in question is called X-53 VIMVAR. Investigators investigating the Yakushima accident found that the metal gear in question had multiple inclusions, or microscopic weak spots in the metal caused by foreign substances mixed in during the manufacturing process. Weak spots that can lead to fatigue cracking. Since November of last year, there have been seven more incidents attributable to cracks in the gears, likely caused by the same weakness in the metal. Including the latest emergency landing.

Today, Defense Secretary Austin met with Prime Minister Shigeru Ishiba and senior officials in Japan to reaffirm the importance of the alliance between the two countries and Washington's commitment to regional security as threats from China and North Korea increase. Japan had already been informed of the precautionary measure regarding the Ospreys in recent days, both because it has 15 units for its own Defense, and because several American examples are stationed there to support US forces in the country.

The Bell Boeing V-22 Osprey is known for its advanced architecture: it is equipped with steerable rotors that allow it to perform vertical takeoffs and landings similar to helicopters, but with the ability to transform and fly like an airplane. From the model's entry into operation until November 2023, it has been involved in twelve serious air accidents that have resulted in the deaths of 32 people.