PT6's that let go....
 

Last week I had a PT6-27 failure, well more of a very quick precautionary shutdown.

Essentially the FCU let go (we did not know at the time, we thought it was a governor failure) we had a massive increase in TQ through red line, but within acceleration limits.

It was un commanded and uncontrolled so we had to shut it down.


Now I have heard of FCU's that have had scheduling problems but never one that just let go.
We believe that the spline let go and are awaiting a report from Pratt.

Has anybody else had this happen ?????

Just curious.
:(

[ 08 July 2001: Message edited by: TWOTBAGS ]

[ 08 July 2001: Message edited by: TWOTBAGS ]

You may find it interesting to know the PT6 FCU spline is actually made out of plastic and is quite small in diameter. In addition the fuel pump spline can get fuel washing out lubricant form the drive bearing also leading to both pump and FCU failure. The stiry goes an engineer leaves the spline out, starts engine with FCU scheduling full fuel during start, I think you can guess what happens next!!!!!! :eek:

Yep recently had a mate in an EMB120 have a FCU go on them - Tq fluctuations and then shutdown, not sure on the specifics regarding the FCU. One morning at 6am I had a PT6-27 let go with an almighty bang - FOD they said?? That sure woke me up in a hurry at 300ft after take off - and I thought it was pistons that had the greater % of failures!! :eek:

The No1 bearing let go shortly after t/o in a PT6A-41 powered Beech Catpass King Air 200.Catastrophic failure, destroyed everything inside. Bearing had 1200 hours since being fitted by Revima. P&WC said - **** Happens.

Trust in God and Pratt & Whitney! I would choose the Good Lord - and I am an agnostic!

I had a 300hr since zero-timing PT-6-6 go bang on me for no reason. The course of the failure was found but not the cause. On another engine (PT-6) an engine failure was causeddue to overtemp. The TIT feeler was temperature damaged thus reading too low!

Nothing to do with FCU's, just for interest.

we had power fluctuations (200ft/lbs)on o PT6A-42. worn out spline. whole fcu replaced engine is fine now.
Unscheduled pwr-increase happend to a friend of mine in a Beech C90B ( is it the -27 engine ? i don´t recall it... getting old...)

Airking,
-20 DHC6-100/200
-27 DHC6-300
-34 DHC6-300 (mod) and Bandit.
;)

I've had an uncommanded TQ-increase in a DHC6-300 (PT6A-27) last year, while we were 2 hours out of Colombo over the Indian Ocean. I saw the needle move through the redline and pulled the power back immediately. At FL110, prop full fine and power lever in idle, the engine was producing around 30 PSI TQ.
We were able to equal all engine parameters, but kept a 6" power lever split. We shut the engine down in the approach.
We had another FCU shipped out and continued with that. I was told that the problem is probably related to clogging or leaking of internal lines or bellows.

Erik.

BTW, there's a new STC to install -34s and 4-bladed props on a DHC6-200. The TQ-limit remains 42.5 PSI, but you can still get it at high-altitude.

[ 15 July 2001: Message edited by: erikv ]