Originally Posted by
falcon20pilot
Thomas were the failures attributable to FOD and if not was the cause known after tear down? And are you sure it was the power turbine and not the compressor turbine? The only failure I have had in managing over 25,000 hours on 90 series King Airs has been the compressor turbine disk, and both times technically due to FOD. Not saying we have not worked on power sections, but we caught those due to strange noises in the reduction gear box or power section prior to catastrophic failure.
One was a complete melt down of the compressor turbine which took out the power turbine. The 2nd one was a melt-down of the compressor turbine. The power turbine was damaged at the same time. Very long story associated with the 2nd one.
I've also heard of a time a shaft bearing began to fail allowing the shaft to wonder and vibrate so badly it broke the #3 bearing surface free from the rest of the case.
As far as i know, all of the failures were not associated with FOD. We do allot of temp changes compared to "start, takeoff, cruise, land, shutdown" type of flying. Some of our engines have 5+ times more start/shutdown cycles than they do hours.