Operators of certain Airbus A320neo-family aircraft are being instructed to de-pair Pratt & Whitney PW1100G engines over low-pressure turbine blade damage.
The European Union Aviation Safety Agency says the engine manufacturer has developed an improved third-stage disc turbine blade.
Examination of damaged blades has shown that they have “limited” damage tolerance, says EASA, and an impact originating internally or externally could result in “instantaneous” blade fracture.
Replacement of the blades is the subject of a service bulletin.
But EASA is intending to reduce the risk of a dual in-flight shutdown of PW1100G engines on A320neo and A321neo jets while the modifications are being conducted.
Within three months, says EASA, operators must ensure that aircraft with two affected powerplants have their engines de-paired.
EASA has listed 170 aircraft affected by the directive.
The US FAA has issued a directive on blade replacement, effective 16 December, after more than 40 failures of the third-stage low-pressure turbine blades over the last three years.
EASA has opted not to adopt this FAA directive, however, choosing instead to require the engine de-pairing, ahead of adopting a separate FAA order aimed at addressing the blade replacement during the next engine shop visit.