AD FAA-2021-0191

The FAA proposes to supersede Airworthiness Directive (AD) 2019-21-11 and AD 2020-07-02. AD 2019-21-11 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 2020-07-02 applies to all PW PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, and PW1525G- 3 model turbofan engines. AD 2019-21-11 requires initial and repetitive borescope inspections (BSIs) of the low-pressure compressor (LPC) rotor 1 (R1) and, depending on the results of the inspections, replacement of the LPC. AD 2020-07-02 requires the removal from service of certain electronic engine control (EEC) full authority digital electronic control (FADEC) software and the installation of a software version eligible for installation. Since the FAA issued AD 2019-21-11 and AD 2020-07-02, the manufacturer developed a new version of EEC FADEC software, which terminates the need for repetitive BSIs of the LPC R1. This proposed AD would continue to require repetitive BSIs of certain LPC R1s until replacement of EEC FADEC software with the updated software. This proposed AD would require a BSI after installation of the updated EEC FADEC software if certain Onboard Maintenance Message fault codes are displayed and meet specified criteria. The FAA is proposing this AD to address the unsafe condition on these products.