Came across this recently. RA-Aus have mandated the installation of manifold guages on aircaft with constant speed or in-flight adjustable props.
Do you think this would be required based on the comments? Do they put undue stress on an engine? This includes electrically adjustable in-flight units on many aircraft.
http://www.auf.asn.au/airworthiness/AN200808-1.doc
I can't see CASA issuing a statement like this:
Background:
Some recent reports have highlighted problems with aircraft engine crankshafts failing having been placed under abnormal stress from the In-flight Adjustable propeller in flight.
Action Required: - On or before the next periodic inspection fit a manifold pressure gauge to all aircraft fitted with constant speed or flight adjustable propellers.