Several new engine failures involving the Pratt & Whitney PW1100G engine will cause a “limited number” of Airbus A320neo family aircraft to stop flying until they are fitted with spares, European aviation safety regulators and Airbus say.

The problem applies to a batch of recently delivered geared turbofan engines with serial number P770450 and after, the European Aviation Safety Agency states in a 9 February emergency airworthiness directive. Those engines are fitted with aft hub modification in the high pressure compressor, EASA says.

Several A320neo family aircraft have experienced engines failures in flight or during take-off, EASA states. The root cause remains under investigation, but the preliminary findings suggest that engines with the aft hub modification are “more susceptible” to an in-flight shutdown, EASA adds.

P&W clarifies that the preliminary finding indicates the problem is with the knife edge seal on the modified aft hub of the high pressure compressor.

“The efforts of both companies are directed to support customers and operators to minimise any disruption,” Airbus says, referring to itself and P&W.

EASA has ordered operators to ground aircraft within three flight cycles if both engines have the aft hub modification. If an aircraft has only one engine with the aft hub modification, it must stop flying extended routes over water within one flight cycle, EASA says.

It was not immediately clear if the recent aft modification is related to the geared turbofan engine family’s other known durability issues. Those include an air seal in the No. 3 bearing and a compressor liner that wear out years faster than the design requirement. P&W had resolved both of those problems in the fourth quarter last year, parent company United Technologies reported last month.

The order to replace engines affected by the emergency airworthiness directive will further strain the demand on P&W’s pool of spare engines. The company has set aside about 40-45 engines to serve as spares while previously delivered engines are taken off wing to incorporate the durability upgrades.

Airbus offers customers a choice of engines for the A320neo family, including the CFM International Leap-1A. Eight customers operate 113 A320neo family aircraft with P&W engines, Airbus says.

P&W engines have flown 500,000h since the first geared turbofan-powered A320neo entered service in January 2016 with Lufthansa, P&W says.

Source: Cirium Dashboard