Summary
We propose to supersede an existing airworthiness directive (AD) that applies to all Pratt & Whitney Canada Corp. (P&WC) PW118, PW118A, PW118B, PW119B, PW119C, PW120, PW120A, PW121, PW121A, PW123, PW123B, PW123C, PW123D, PW123E, PW123AF, PW124B, PW125B, PW126A, PW127, PW127E, PW127F, PW127G, and PW127M turboprop engines. The existing AD currently requires initial and repetitive inspections of certain serial numbers (S/Ns) of propeller shafts for cracks and removal from service if found cracked. Since we issued that AD, we determined the need to add a mandatory terminating action for the repetitive inspections. This proposed AD would require initial and repetitive inspections of certain S/Ns of propeller shafts for cracks and removal from service if found cracked, and would require removal from service of affected propeller shafts as mandatory terminating action to the repetitive inspections. We are proposing this AD to detect propeller shaft cracks, which could cause failure of the shaft, propeller release, and loss of control of the airplane.