A new Federal Aviation Administration proposed rule reveals that more GE Aerospace turbofans may include compressor components made from contaminated material.
Released by the US government on 1 September, the proposal would, if finalised, require airlines to replace certain components inside some GE90s “before further flight”.
Affected parts include high-pressure turbine discs and rotor spools, and compressor seals.
The FAA’s proposed airworthiness directive (AD) marks the latest in a string of regulatory orders responding to findings that several types of GE Aerospace engines contained components manufactured using what the FAA calls “powered metal material suspected to contain iron inclusion”.
“Iron inclusion is attributed to deficiencies in the manufacturing process and may cause reduced material properties and a lower fatigue life capability, which may result in premature fracture and subsequent uncontained failure,” the FAA’s latest proposal says.
GE says the proposal “is consistent with existing GE recommendations to operators and reflects our proactive approach to safety management”. It adds that the issue does not present a flight-safety risk and that it understands the problem and is taking corrective steps.
In 2022, the agency issued ADs saying a small number of GE90s, GEnx and CFM International Leap turbofans might have components produced using similarly contaminated material. Then, this year, regulators said more Leaps and GEnx engines might be affected.
GE Aerospace, which co-owns CFM with Safran Aircraft Engines, produces Leap compressor, combustor and high-pressure turbine parts. Leap engines power Boeing 737 Max and Airbus A320neo-family jets, while the GEnx equips 787s and the GE90 777s.
The FAA’s latest proposed order comes after GE discovered that more components inside GE90s were made from material used to produce other components in which it had found iron inclusion defects.
The proposal is set to become a final order after a 45-day comment period ends. If finalised, it would require airlines to replace some affected GE90 first and second stage high-pressure turbine discs before further flight. Airlines would have more time to replace some other affected components.
“This condition, if not addressed, could result in uncontained debris release, damage to the engine and damage to the airplane,” says the FAA.
GE Aerospace has already notified airlines of the issue, it adds.
The company is not alone in dealing with manufacturing defects involving metallic engine components.
In July, Pratt & Whitney disclosed that some 1,200 of its PW1000G geared turbofans – a variant of which also powers A320neo-family jets – might contain high-pressure turbine discs produced using potentially “contaminated” powered metal.
