The Federal Aviation Administration plans to place new maintenance requirements on airlines after learning that more components in Pratt & Whitney (P&W) PW1100G engines may be affected by a powder-metal manufacturing problem.
P&W says the proposed requirements fall within the scope of its previously disclosed comments about the impact of the powder-metal issue.
The FAA laid out new proposed requirements in a regulatory filing released on 11 December, saying some PW1100G rotors, hubs and air seals will need “accelerated replacement” due to the manufacturing issue.
The proposal would affect 430 US-registered PW1100Gs, which power Airbus A320neo-family jets.
P&W earlier this year said it needed to recall some 1,200 PW1100Gs for inspection or replacement of high-pressure turbine and compressor disks, citing a problem involving powder-metal manufacturing. As a result, it said, hundreds of A320neo-family jets will need to be grounded at any given time in the coming year for inspections and parts replacements.
P&W said several weeks ago that it expected the FAA would soon issue airworthiness directives related to the new maintenance requirements.
The FAA’s new proposal ”is consistent with the actions published in Pratt & Whitney Service Bulletins/Special Instructions previously released to operators. There is no expansion of scope. We continue to work closely with our customers and operators on our fleet management plan,” P&W tells FlightGlobal.
“There is an increased risk of failure for additional powder-metal parts in certain powder-metal production campaigns,” the FAA’s 11 December proposed rule says. “All affected parts are susceptible to failure significantly earlier than previously determined.”
The FAA has issued several recent PW1100G airworthiness directives addressing the powder-metal problem, which came to light after an International Aero Engines (IAE) V2500 turbofan suffered a high-pressure turbine disk failure in 2020. P&W co-owns IAE and makes V2500 and PW1100G blades using the same process.
In response, the FAA in October 2022 required airlines to complete ultrasonic inspections of PW1100G high-pressure turbine disks. In August, it tightened the inspection timeline after a PW1100G suffered a failed “integrally bladed rotor”, also called a blisk – a component in the turbine’s high-pressure compressor.
Now, the FAA’s 11 December proposal says P&W determined that the bladed rotor failed due to “a powder-metal anomaly”. It also says additional PW1100G components than previously known are affected by the problem.
Those components include the bladed rotors, high-pressure compressor hubs, and high-pressure turbine first- and second-stage air seals, hubs and retaining plates, the FAA says.
Of the 430 affected US engines, many will need several of those parts replaced, it adds.
The document also proposes requiring airlines to perform ultrasonic inspections of bladed rotors and hubs.
Story updated on 12 December to include comments from P&W.
