A problem with the clutch on Air Force Special Operations Command’s CV-22 Osprey aircraft has prompted the command to ground its fleet while it tries to find the cause.
In an email to Defense News, AFSOC public affairs director Lt. Col. Becky Heyse said that the command’s 52 tiltrotor Ospreys were grounded on Tuesday due to recent “hard clutch engagement” incidents. Two such problems have happened in the last six weeks, and there were previously two others that occurred since 2017.
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Hard clutch engagement occurs when the clutch connecting the propeller’s rotor gear box to its engine slips. When this happens, Ospreys are designed to transfer the power load from that engine to the other engine immediately, which would allow it to keep operating if an engine failed.
In these incidents, the clutch on the original gear box has engaged and the power load transferred back, within a span of milliseconds. The large transfer of torque causes the Osprey to lurch, and the air crews land immediately. These problems in the past have led to the replacement of Ospreys’ gear boxes and engines, which qualified them as Class A mishaps.
A "Class A mishap" in ZoomieLand is an incident that causes $2.5 million in damages, and/or death, permanent disability or loss of an aircraft.
If you peruse the list of tiltrotor projects going back seventy years, you may notice that only one has ever made it to production. I imagine that there is a reason for that.
"Land immediately" is an interesting turn of the phrase. Though speaking from my single similar experience, it's a good one!
ReplyDeleteKISS and one of Augustines Laws: Anything that isn't in a design won't break.
ReplyDeleteOspreys aren't simple and have a LOT of things that can break.
The ETOPS jape of Engines Turn or Passengers Swim pointed at two engine jets misses a statistical realities: more parts mean more chance of failure: the two engine jets are statistically more reliable than three or four engine jets.
But golly, Ospreys are hot when they work.
more parts mean more chance of failure
ReplyDeleteHence the old joke that a DC-6 was a four-engine airplane with three-bladed props, and a DC-7 was a three-engine airplane with four-bladed props.
Navy wisdom regarding stuff that the Marine Corps flies: Never get onboard anything who's design function is to screw itself into the ground.( I realize these were Air Force birds, but it's more fun when you can lay it off on the Marines.)
ReplyDeleteI just read they are now training the pilots to deal with the problem. One hell of a fix that is.
ReplyDeletew3ski