FAA warns of possible defect in Boeing 777 engines

GE90 turbofans

The proposal, which was published on September 1st, would require airlines to replace the affected components in some GE Aerospace GE90 turbofans before the next flight. The FAA’s latest proposal came after GE Aerospace discovered that more components within GE90 engines were produced using material associated with iron inclusion. The components include high-pressure turbine discs, rotor spools, and compressor seals.

According to the FAA, ‘iron inclusion’ is a result of manufacturing process flaws and could cause early cracks and failures in the components, leading to engine damage and debris release.

GE Aerospace, which is a joint venture between GE and Safran Aircraft Engines, said that the proposal “is consistent with existing GE recommendations to operators and reflects our proactive approach to safety management”.

They also said that the issue does not pose a risk to flight safety and that they are aware of the problem and have implemented corrective actions.

Earlier directives

In 2022, the FAA issued similar directives for other GE90s, GEnx, and CFM International Leap turbofan engines that may have components made with material suspected of containing iron inclusion.

The proposal will be available for public feedback for a period of 45 days prior to becoming a finalized directive. Upon finalization, it will require the immediate replacement of particular GE90 high-pressure turbine stage-one and stage-two discs before the machinery can be operated further. Other impacted components will be granted an extended timeline for replacement.

The FAA warned that failure to comply with this directive could result in uncontained engine failures, damage to the aircraft, and possible injuries. GE Aerospace has already notified the airlines about the issue.

Other engine makers have also faced manufacturing defects related to metal components in their turbofan engines.

In July, Pratt & Whitney reported that around 1,200 of its PW1000G geared turbofan engines, which are used in various aircraft, including the A320neo family, could have high-pressure turbine discs made with material that may be ‘contaminated.’ The problem was initially identified in an Airbus A321ceo plane operated by a Vietnamese carrier. This aircraft was equipped with an IAE V2500 turbofan engine, co-developed with Pratt & Whitney, and experienced a disc failure.

Earlier, Pratt & Whitney discovered that the tainted powder was similarly used in the production of its most recent PW1100G Geared Turbofan Engines. The company has subsequently launched a preemptive recall for inspections, well in advance of its planned schedule.

The GE90 engine

The GE90 is a high-bypass turbofan engine by GE Aviation, designed for the Boeing 777 and first used by British Airways in 1995. It offers thrust ratings between 81,000 to 115,000 pounds-force and was the largest jet engine until surpassed by its successor, the GE9X, in 2020. Developed from NASA's 1970s Energy Efficient Engine and GE's own blade technology, the GE90 had multiple international partners including Snecma, IHI, and Avio. Originally one of three engine options for the 777, it later became the exclusive choice for newer 777 models. The enhanced -115B version was first tested in 2001 and is used in second-generation 777 aircraft.