Wall Street Journal has a long article today (Tues Dec 19) about the latest V-22 Osprey crash in Japan.

After the article this comment was posted by a reader:

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The physics behind many of the crashes of the V-22 over the past 2 decades is well understood. I have a PhD in physics and have been working in aerospace on these types of issues for 20 years. As Dewey Smith says, asymmetric loading of the rotors is impossible to recover from but it is very easy for even experienced pilots to find themselves in that state. The aircraft rely on 200 year old air data technology that everyone knows doesn't work at the low speeds where these accidents happen, that measure air data in the rotor wash and are completely inaccurate, and provide no look ahead information for the control system to be able to respond to. They have known about this since the inception of the aircraft. Both Boeing and Bell/Textron have used look ahead, laser based air data that provide them the information necessary to have prevented these crashes. They have used them in the certification flight tests of the commercial version of the tilt rotor. However, they refuse to incorporate these new capabilities in the V-22 because those at the top refuse to admit they have a problem.
Therefore, so many of our young soldiers are dying. It's criminal and heartbreaking.

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another article in Military.com

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A mechanical failure known as a hard clutch engagement, or HCE, has plagued the Osprey for more than a decade, with at least 15 known incidents occurring between 2010 and 2022.

An HCE happens when the aircraft's clutches -- which when working properly allow for one engine to power both propellers -- jam and shred internal components connected to the rotors.

One essential component that can wear out and lead to a clutch failure is the input quill assembly.

While the incident is still under investigation, the Air Force noted that preliminary indications in the November crash that killed eight airmen indicated a "potential materiel failure."

An Air Force Special Operations Command official told Military.com last week that preliminary findings in the Nov. 29 mishap show that the flight hours on the input quill assembly were likely below the 800 flight hour threshold for replacement that was announced in February.

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https://www.military.com/daily-news...s-are-limiting-their-use-operations.html