Summary
We propose to adopt a new airworthiness directive (AD) for certain Hawker Beechcraft Corporation Model 390 Airplanes. This proposed AD would require you to inspect the starter-generator to determine the serial number (S/N) and suffix letter, which indicates if the part is defective, and replace any defective starter-generator with one of new design. This proposed AD results from reports of a manufacturing error where certain starter-generators may have been improperly shimmed. We are proposing this AD to detect and replace defective starter-generators, which could result in premature starter- generator failure. This failure could lead to increased chances of dual starter-generator failure on the same flight.