FAA issues alert on check valve flaw in some Cessna Caravans

According to a special airworthiness information bulletin issued Nov. 28, the issue affects Caravans commonly referred to as “208B EX” or “EX” that incorporate the Textron PT6A-140 engine installation. The FAA said it was aware of three instances in which check valve part number C100490-1 failed, with parts of the assembly entering the oil system.

“The failure of the oil system check valve is a latent failure condition which may exist on any airplane. Indications the failure has occurred are increasing oil temperatures in to the caution and warning range due to blockage in the oil system,” the SAIB notes.

The FAA recommended replacing any check valve part number C100490-1 that has 1,800 hours’ time in service or greater, on any engine, until further investigation has been conducted, and returning any check valve removed for any cause to Textron Aviation Customer Service at the address provided in the SAIB.