Airbus believes it will still be able to start delivering the A320neo before the end of this year, despite not having a specific timeframe for resuming test flights with the Pratt & Whitney-powered variant.
Flight-testing with the two PW1100G-equipped aircraft â€“ F-WNEO and D-AVVA â€“ has been â€œpausedâ€ since early May, says Airbus, after discovery of a component manufacturing flaw.
Airbus has not indicated when the aircraft might restart their flight campaign, stating only that it is â€œconfidentâ€ of returning them to testing â€œin the coming weeksâ€.
â€œWe remain on track to begin aircraft deliveries in 2015,â€ the airframer adds.
Airbus has previously stated that it would start delivering the PW1100G-powered A320neos from October.
â€œWe had findings during flight testing,â€ it says. â€œTogether with our partner Pratt & Whitney we are currently analysing the situation.â€
Airbus says it understands that the findings relate to a â€œminor partâ€ â€“ a retaining ring holding a seal.
â€œIt is the mission of flight-testing to find issues before entry into service to ensure the highest maturity from day one,â€ it adds.
Airbus programmes chief Didier Evrard, speaking in Toulouse in late May, indicated that the seal was located between the high-pressure compressor and the rest of the engine.
The seal is retained by clips, he said, and there had been â€œsome production batchesâ€ which had shown â€œslightly more deviations when running, when exposed to temperatureâ€.
Evrard said he believed a thermal treatment problem was behind the finding, and said that the retaining rings would be replaced.
Another source familiar with the situation says the issue relates to a bracket beneath the combustor which holds the seal in place but which became disengaged, adding that this has been traced to the manufacturing process rather than the component design.
Pratt & Whitney says that it â€œunderstandsâ€ the cause of the flight-testing findings and the company is â€œaddressing themâ€.
It is similarly confident that testing will restart in the â€œcoming weeksâ€ and that it is ready to support service entry in the â€œfourth quarterâ€.
Testing has continued with a third A320neo, F-WNEW, which is fitted with the rival CFM International Leap-1A engine. It carried out its maiden flight on 19 May.