AD 2021-14-06 Continues To Require Repetitive BSIs Of Certain LPC R1s Until Replacement Of EEC FADEC Software

The FAA is superseding Airworthiness Directive (AD) 2019-21-11 and AD 2020-07-02. AD 2019-21-11 applied 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 applied to all PW PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, and PW1525G-3 model turbofan engines. AD 2019-21-11 required 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 required 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. This AD continues to require repetitive BSIs of certain LPC R1s until replacement of EEC FADEC software with the updated software. This AD 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. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective August 12, 2021.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2019-21-11, Amendment 39-19777 (84 FR 57813, October 29, 2019), (AD 2019-21-11) and AD 2020-07-02, Amendment 39-21106 (85 FR 17742, March 31, 2020), (AD 2020-07-02).

AD 2019-21-11 applied to certain PW PW1519G, PW1521G, PW1521GA, PW1524G, PW1525G, PW1521G-3, PW1524G-3, PW1525G-3, PW1919G, PW1921G, PW1922G, PW1923G, and PW1923G-A model turbofan engines. AD 2020-07-02 applied to all PW PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G33, PW1525G, and PW1525G33 model turbofan engines.

The NPRM published in the Federal Register on March 26, 2021 (86 FR 16137). The NPRM was prompted by reports of in-flight shutdowns due to failure of the LPC R1 and by subsequent findings of cracked LPC R1s during inspection. Additionally, the manufacturer performed further root cause analysis of the LPC R1 failures and determined the need to update the EEC FADEC software to automate rotor speed management and limit the maximum climb and maximum continuous thrust ratings. In the NPRM, the FAA proposed to retain certain requirements of AD 2019-21-11 and none of the requirements of AD 2020-07-02. In the NPRM, the FAA proposed to continue to require a BSI of certain LPC R1s for damage and cracks and, depending on the results of the BSI, replacement of the LPC R1. In the NPRM, the FAA proposed to continue to require repetitive BSIs of certain LPC R1s until replacement of the EEC FADEC software with the updated software. In the NPRM, the FAA also proposed to require a BSI of the LPC R1 after installation of the updated EEC FADEC software if certain Onboard Maintenance Message fault codes are displayed and meet specified criteria.

FMI: www.regulations.gov