Had a -28 go out on a king air once. Starting the decent out of fl220, as I reduced the power the left engine started compressor stalling. I put the power back up and everything ran fine until I brought back the power back before the final app fix where it really made some loud bangs. Again I increased the power and it went away until short final where all hell broke loose. The engine started surging, the torque and fuel flow fluctuated with every bang. At this point we were already commited to landing so we touched down and went into a little reverse as we slowed down. The thing didn't stop coughing until we came out of high idle. When taxing to park each time the engine accelerated out of idle the engine gave off a Garrett howl like on the MU-2.

Turns out what happened was the oil pump started to fail and the insides started eating into the housing. It caused enough drag in the 85-71% n1 range to cause a compressor stall. It never even have off a chip detect or decrease in oil pressure. Needless to say, I'm glad it happened that way, I couldn't imagine what a complete oil starved pt-6 sounds like as it welds itself together.

The engine was 3600 since new I believe.

 

It's not really that exciting, actually. You'll likely have shut it down by then, as complete oil loss (if occurring) is detected through the propeller. If the engine freezes and isn't shut down, it may run hot and you'll end up with a core lock and simply fuel chop it. Either way, it's done, and should ultimately run to feather.

 

lol well thanks

 

I'm thinking about working for them, been trying to find out what caused the failure- anyone know?

 

I had a Fuel Control Unit fail in a King Air 90 one night climbing through 5,000 feet. Naturally the weather was about a mile and a half visibility with 200 foot ceilings as I'd just departed UTA. It caused a torque runaway & I had it shut down in about 8 seconds. I was light with no pax. It flew just fine on one. I did a SE ILS into MEM - 18L as I recall. Hard to taxi on one....LOL!

Luckily, I'd trained at SimCom for just such an occurrence and the training was excellent. This engine had about 1,400 hrs SOH I believe.

 

I had one hard seize on takeoff from an outlying field near Yuma many Moons ago in a UC-12B. The torque from the seizure broke two of the three engine mounts. The good engine brought us back to the field with no problems.

 

Used to work for an operator that flew seasonally in the Caribbean. My last season down there, one of the Caravans lost a blade on a takeoff roll, fortunately at a point where the takeoff could be aborted. Despite regular compressor washes, it was attributed to corrosion, I believe.

 

When I was flying the BE-1900D for Air Midwest the left engine auto shutdown during cruise. They found the P3 line to fuel control unit had broke.

 

When I was flying a Dash 7 for Pan Am Express, the number four engine shut down during cruise, unknown reason.

We also had a Dash 7 number two engine experience an uncontained failure while landing in ALB. Turbine blades pierced the cabin and injured several passengers.

 

Over 8,000 hours behind various PT-6 engines in all types of weather, over all types of terrain. I love those engines more than my wife! Thanks Pratt &Whitney!