Know your PT6A - Pratt & Whitney Canada

Cycle Counting
Certain rotating components of the engine have a limited life based upon
the number of operating cycles they experience. These lives are quoted
in the Rotating Component Lives Service Bulletin for each PT6A engine
model. It is important to continuously record the number of operating cycles
and partial cycles to track rotor lives. Rotor components not supported
by proper documentation are to be removed from service. Prior to engine
servicing, the total cycles and all flights and starts must be recorded in the
appropriate engine logbook.
At engine overhaul, a calculation will be made of the remaining service life
for each rotating component. This calculation is based upon the rate of
cycle accumulation recorded in the engine logbook.
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