Pratt & Whitney expects to have rectified issues with the knife edge seals on the in-service fleet of PW1100G geared turbofan engines by the middle of 2019.
In an email to FlightGlobal, P&W's president commercial engines, Chris Calio admits that while it has caught up on replacing faulty seals on new engines, it will still take time for redesigned seals to be fitted to those engines already in service.
"Naturally, there are engines that are flying today which will require time off-wing to install the fixes, so we will continue to witness removal events for these engines. We anticipate resolving these engine removals by mid-2019," says Calio.
A new knife edge seal issue was discovered in January after four Airbus A320neos experienced engine shutdowns on take-off or during flight. P&W chief executive Bob Leduc previously said the engine’s original knife edge seal was delivered with a design flaw that required an inspection after a certain interval of flight hours.
A redesigned seal was introduced into the production system late last year, but made the problem worse. Instead of merely an inspection requirement, the new seal caused the engine to shut down.
P&W has since resumed shipments of PW1100Gs to Airbus with a previous design of a knife edge seal that does not have the flaw.
"While admittedly, the issues we have had did cause a delay in deliveries from Airbus, we are now back on track on our deliveries of the GTF engines, and will continue to ramp up in our deliveries commitments," adds Calio.
P&W says that it is also "applying lessons learned in-service" from the PW1100G-JM and PW1500G engines to the PW1200G that powers the Mitusbishi Aircraft MRJ regional jet.Mitsubishi temporarily grounded its MRJ regional jet flight test fleet last year, following an engine flameout on one of its test prototypes on 21 August. While testing resumed in September, P&W did not specify the cause of the incident.
"We’re able to weave improvements into the still-nascent MRJ production line, and there are development plans in-place to ensure root causes are addressed in the PW1200G programme. The ability to rapidly learn and accelerate improvements across the GTF engine family is a significant advantage," explains Calio.
The engine manufacturer adds that it is still in discussions with Boeing to explore how best it is able to meet the airframer's specificification and production timelines for its New Mid-market Aircraft (NMA).
Calio says that its GTF architecture is scalable “to meet existing and potential customer demands, including but not limited to Boeing’s New Mid-market Airplane.”