Pilot Proficiency

On the Record: Schweizer 269C

Thursday, November 17, 2016 at 03:41 AM ET

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Key Takeaways:

A Schweizer 269C helicopter crashed during a night orientation flight, resulting in two fatalities, after witnesses heard unusual engine sounds including a high-pitched squealing and apparent power loss.
The investigation determined the probable cause was a complete loss of translational/rotational power between the engine and transmission due to severe wear on the forward spline portion of the lower coupling drive shaft.
This severe wear was likely caused by a loss of lubrication in the rubber boot for the spline, which was missing post-crash, or an alignment issue.
The definitive root cause for the severe spline wear could not be determined due to extensive fire damage and unrecovered components.

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Schweizer 269C

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