FAA To Mandate Engine Software Upgrade For A220s, E2s

WASHINGTON—Pratt & Whitney has released updated engine control software that eliminates the need for repetitive inspections put in place to prevent damage that led to four Airbus A220 infight shutdowns; the FAA plans to mandate its installation. 

A draft airworthiness directive (AD) set for publication March 26 proposes giving operators of PW1500G and PW1900G engines, which power A220s and Embraer E-Jet E2s, respectively, 120 days to install the updated full authority digital electronic control (FADEC) software. Once in place, operators would no longer face repetitive borescope inspections (BSI) of low-pressure compressor (LPC) stage one rotors (R1s) that must be done as often as every 15 cycles for certain low-time engines. 

Pratt detailed the software upgrades in February service bulletins, calling for installations of version V2.11.10.4 on the PW1500G-powered aircraft and V9.5.6.7 for aircraft with PW1900Gs.  

Several versions of FADEC software have been released since the 2019 incidents, including one version that the FAA and other regulators required operators to install. The latest versions are the first that relieve operators of inspections that FAA and other regulators mandated in response to the engine failures.

“The manufacturer developed a new version of EEC FADEC software, which terminates the need for repetitive BSIs of the LPC R1,” the FAA explained in the draft AD. “This proposed AD would continue to require repetitive BSIs of certain LPC R1s until replacement of ... FADEC software with the updated software.” 

The incidents happened between July 2019 and February 2020 and involved three SWISS A220-300s and one Air Baltic A220-300. In all four incidents, LPC R1s failed. Subsequent checks of other engines found more cracked R1s. 

Pratt determined that the LPC R1 damage and related engine failures were caused by LPC vane schedules—software settings that adjust vanes to maximize engine efficiency— that led to an acoustic resonance. The newer software versions automate rotor speed management and limit maximum climb and maximum continuous thrust ratings, the FAA said.