After more than a dozen MV-22 Osprey incidents involving what is known as a hard clutch engagement, or HCE — including one that claimed the lives of five Marines — military officials now say that they have finally made progress in understanding the deadly issue.
“While the ultimate root cause has not yet been verified, the HCE team has narrowed down the scope of the investigation to a leading theory,” Neil Lobeda, a spokesman for the Osprey’s Joint Program Office, told Military.com in an email.
That theory, according to Lobeda, is something called “out of phase engagement.”
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The Osprey is unique in that it is a tilt-rotor aircraft, meaning it lifts off like a helicopter but flies like a traditional airplane. With that design, it also means that the Osprey is limited in its ability to recover from an issue, should one occur.
Unlike fixed-wing aircraft, it is not able to be equipped with ejection seats or glide to a landing. It also isn’t able to make use of “autorotation” — a safety maneuver helicopters use where the engine is disengaged and the rotors spin as air moves past them while descending.
As a result, it is equipped with a complex system of clutches and linkages that are designed to address a situation where the aircraft loses power in one engine. That system enables the second engine to still turn both propellers and…
