Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Pratt & Whitney (PW) JT9D series turbofan engines. This proposal would require initial and repetitive in-shop eddy current and on-wing ultrasonic inspections of the Combustion Chamber Outer Casing (CCOC) forward flange (L flange) fillet radius for cracking, and replacing cracked L flanges with serviceable parts. Replacement with an improved L flange constitutes terminating action to the repetitive inspections. This proposal is prompted by reports of CCOC rupture due to cracking in the L flange fillet radius. The actions specified by the proposed AD are intended to prevent CCOC rupture due to cracking, which could result in an uncontained engine failure and damage to the aircraft.