PPRuNe Forums - View Single Post - Helicopter down outside Leicester City Football Club
Old 6th Dec 2018, 15:04
  #912 (permalink)  
Onceapilot
 
Join Date: Oct 2012
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Originally Posted by [email protected]
My reading of this is that the duplex bearing was overheating, binding and then seizing, causing rotation of the control shaft which undid the castellated nut and removed the pitch control of the TR allowing the servo to go to the 'full right pedal' position.

I don't care how many times you practice in the sim, that one is pretty unrecoverable from that height and speed.

The question is - is this an assembly issue (bearing end nut over torqued) or a maintenance issue? The aircraft was quite young.......
The report seems to be a little confusingly worded. I agree, the duplex bearing at the spider end seems to have failed and then spun the shaft. Result, the castleated nut at the input end of the shaft has spun, with the shaft, against the pin-carrier, until the nut friction-welded to the pin-carrier and then the split pin was sheared and the nut unscrewed and disconnected the input. That is the way I read it. There does not seem to be any prejudice against the assembly in that. The duplex bearing failure looks to be the culprit from my interpretation.

OAP

Last edited by Onceapilot; 6th Dec 2018 at 15:09. Reason: Castleated nut spun against the pin-carrier
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