P70 cool down problem
 

My P70 has developed the following problem. After flying, when the turbine is shut down & the cool down sequence starts. the starter cannot spin the turbine as it appears to be to tight. After a couple of minutes everything is free again. The bearings are not noisy & the turbine operates perfectly. Something appears to be rubbing when the turbine is trying to cool down.

RE: P70 cool down problem
 

one of my P-70s did the same thing, i sent it into Bob and had the NGV opened up a little and never had another problem, the tolerance was just a little too tight and as things started cooling off they closed up enough to drag.

RE: P70 cool down problem
 

The NGV could be tight, or possibly there is some "crud" (technical term) on the inside of the EGV.

The NGV might also be out of round if the rear mounting screws have come loose.

If the problem becomes severe then send it in for service.

Hope that helps,

RE: P70 cool down problem
 

My p60 has been doing that for the last 2 years but does not loosen after cool-down. It was sent in under my warranty but was not resolved to any extent except to say that it may have been due to the dusty env. in Tucson or free running bearings that accumulated on one side of the races after running. My solution is to spin the turbine manually as part of my preflight procedures. It is not a hard lock-up but may wear out the starter O-ring. Otherwise it has been a great running turbine. Dave