Summary
The FAA is proposing to adopt a new airworthiness directive (AD) that applies to Honeywell International Inc. (formerly AlliedSignal Inc., Garrett Turbine Engine Company, and AiResearch Manufacturing Company of Arizona) TPE331-10 and -11 series turboprop engines with certain part numbers and serial numbers of first stage turbine disks. This proposal would require initial and repetitive fluorescent penetrant inspections (FPIs) and eddy current inspections (ECIs) of the affected first stage turbine disks. This proposal is prompted by a report of a first stage turbine disk found cracked at the disk bore. We are proposing this AD to prevent cracked first stage turbine disks from causing uncontained disk separation, resulting in engine damage and shutdown.