Summary
We propose to supersede an existing airworthiness directive (AD) that applies to all Pratt & Whitney (PW) JT9D series turbofan engines. The existing AD currently requires revisions to the Airworthiness Limitations Section (ALS) of the manufacturer's Instructions for Continued Airworthiness (ICA) to include required enhanced inspection of selected critical life-limited parts at each piece-part opportunity. Since we issued that AD, PW has added mandatory inspections for certain critical life-limited parts. This proposed AD would require additional revisions to the JT9D series engines ALS sections of the manufacturer's ICA. This proposed AD results from the need to require enhanced inspection of selected critical life-limited parts of JT9D series engines. We are proposing this AD to prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.