Comment Period Open Through May 15

The FAA has issued an Airworthiness Directive for all all Pratt & Whitney (PW) PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, and PW1525G-3 model turbofan engines. These engines power Airbus A220 airplanes.

The AD 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. It was prompted by reports of four in-flight shutdowns (IFSDs) due to failure of the low-pressure compressor (LPC) rotor 1 (R1) and by subsequent findings of cracked LPC R1s during inspections.

The FAA has received reports of four instances of IFSDs occurring on the affected model turbofan engines since 2019. In response to the two IFSDs that occurred in July and September 2019, and in response to ongoing investigations of these IFSDs, the FAA issued AD 2019-19-11 (84 FR 50719, September 26, 2019), to perform inspections of the LPC R1 to prevent failures. The FAA subsequently superseded AD 2019-19-11, issuing AD 2019-21-11 (84 FR 57813, October 29, 2019) in response to another IFSD and to expand the population of affected engines that needed inspection of the LPC R1.

Since the effective date of AD 2019-21-11, another IFSD occurred in February 2020. Analysis by the manufacturer determined that the LPC vane schedules were putting the engine in a condition to experience an acoustic resonance that damages the LPC R1, which then leads to LPC R1 failure. In response, the manufacturer updated the EEC FADEC software to improve vane scheduling to avoid acoustic resonance.

This condition, if not addressed, could result in uncontained release of the LPC R1, damage to the engine, and damage to the airplane.

The FAA estimates that this AD affects 58 engines installed on airplanes of U.S. registry. Replacing the software is estimated to take about 2 hours at $85 per hour for a cost of $170 per engine.

The FAA must receive comments on this AD by May 15, 2020.

(Image from file)

FMI: AD