Fixing the knife-edge seal problem

IndiGo and GoAir A320neo aircraft suffered aborted take-offs (two and one respectively) as a result of the PW1100G-JM geared-turbofan knifeedge seal issue.
H Goussé/Airbus

IRONICALLY, THE action by the Indian DGCA came two weeks after a February 21 announcement by UTC CEO Hayes to financial analysts that Pratt & Whitney had already resolved the new PW1100G-JM technical issue by replacing the modified knife-edge seals with seals of the previous design. The December modification to the knife-edge seal “did not play out as expected”, Hayes admitted, but he added that Pratt & Whitney had resolved the issue – obtaining approval for the fix from EASA and Airbus in the process – and had already resumed PW1100G-JM production by February 21.

However, by then the issue had caused Pratt & Whitney’s GTF production programme some temporary damage. P&W’s urgent need to focus on resolving the knife-edge seal safety issue forced the engine manufacturer to halt all production of PW1100G-JM A320neo engines for the first half of February and it also had to recall the 43 affected in-service engines and the 55 engines delivered to Airbus but not yet installed so that P&W could replace their modified knife-edge seals with seals of the previous design.

Addressing the audience at United Technologies’ Annual Investors and Portfolio Managers Meeting in Palm Beach Gardens, Florida on March 16, Pratt & Whitney president Robert Leduc said all 43 in-service engines affected by the knife-edge seal issue would be flying again in airline service by the end of April.

Leduc confirmed that statement included the affected engines on aircraft operated by IndiGo and GoAir, as well as all affected engines operated by other carriers elsewhere.

Additionally, Leduc told the meeting’s audience that by March 15, the day before the UTC investor meeting, P&W had received back from Airbus 22 of the 55 affected engines which had yet to be installed on new A320neo-family aircraft. Airbus would send back to Pratt & Whitney the remaining 33 affected engines by the end of April, he said.