Action
Notice of proposed rulemaking (NPRM).
Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2021-14-06, which applies to all Pratt & Whitney (PW) PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, PW1525G-3, PW1919G, PW1921G, PW1922G, PW1923G, and PW1923G-A model turbofan engines. AD 2021-14-06 requires repetitive borescope inspections (BSI) of certain low-pressure compressor (LPC) rotor 1 (R1) until replacement of electronic engine control (EEC) full authority digital electronic control (FADEC) software with updated software. AD 2021-14-06 also requires a BSI after installation of the updated EEC FADEC software if certain Onboard Maintenance Message fault codes are displayed and meet specified criteria. AD 2021-14-06 also requires, depending on the results of the BSI, replacement of the LPC R1. Since the FAA issued AD 2021-14-06, the manufacturer redesigned the compressor intermediate case (CIC) assembly to incorporate a shortened bleed duct configuration and updated the EEC FADEC software. This proposed AD would continue to require repetitive BSI of certain LPC R1s until replacement of EEC FADEC software with updated software and also a BSI after installation of the updated EEC FADEC software if certain Onboard Maintenance Message fault codes are displayed and meet specified criteria. This proposed AD would continue to require, depending on the results of the BSI, replacement of the LPC R1. This proposed AD would also require removal and replacement of the existing CIC assembly with a CIC assembly eligible for installation. The FAA is proposing this AD to address the unsafe condition on these products.