According to the US Federal Aviation Administration (FAA), it has issued a new proposal to address a potential defect in some of the engines that power Boeing B777 aircraft. The concern is related to ‘iron inclusion’ which could affect the compressor components’ quality and durability.
Boeing B777’s GE90 Engine Faces Possible Defects
On September 1, 2023, the FAA issued an Airworthiness Directive (ADs) for General Electric Company Engines, specifically the GE90 engines that power the B777s. This proposed AD was prompted by a manufacturer investigation that revealed certain high-pressure turbine (HPT) stage 1 disks, HPT stage 2 disks, forward HPT rotor seals, interstage HPT seals, and stages 79 compressor rotor spools were manufactured from powder metal material suspected to contain iron inclusion.
This proposed AD would require affected airlines to replace certain components inside some GE90s before the next scheduled flight.
The FAA’s latest proposal says:
“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.”
FAA-2023-1647
With the AD released, GE has communicated with affected operators regarding the proposed corrective action for this unsafe condition. As a result, affected operators are already aware of the proposed corrective action and have already performed the actions proposed in this AD.
Which Aircraft Uses GE90 Engines?
General Electric’s GE90 turbofan engines are very famous among the Boeing B777 family. The engine has been specifically designed for the B777 variants since the 1990s and has been continuously upgrading with the latest technologies.
Currently, it is estimated that there are around 1,015 aircraft that operate with the GE90 engines. A few of the notable airlines include Emirates and Qatar Airways.
Earlier Directives on GE90 Engines
This is not the first time the FAA has issued an AD, last year the FAA issued similar directives for some GE90s, GEnx, and CFM International Leap engines that may have components produced using similarly contaminated material, suspected of containing iron inclusion.
The current proposal will undergo 45 days of public feedback before it will be a final order in which operators of affected aircraft must comply with the immediate replacement of affected parts. The FAA emphasized that “This condition, if not addressed, could result in uncontained debris release, damage to the engine, and damage to the airplane. The FAA is proposing this AD to address the unsafe condition of these products.”
Manufacturing Defects on Turbofan Engines
This is not the first time the turbofan engines had contamination issues. Back in July, Pratt & Whitney reported that around 1,200 of its PW1000G geared turbofan engines that power the A320neo family might contain high-pressure turbine discs produced using potentially “contaminated” powered metal.
This concern was initially identified by a Vietnamese carrier that operated the Airbus A321ceo variant after a disc failure occurred from an IAE V2500 turbofan engine, which is co-developed with Pratt & Whitney.
Summary
On September 1, 2023, the Federal Aviation Administration (FAA) issued an Airworthiness Directive regarding a potential defect in some of the GE90 engines that power Boeing B777 aircraft. The issue was similar to the past issues where powdered metal materials could affect the compressor components’ quality and durability.
There are currently thousands of GE90 engines used by numerous B777 operators and General Electric has already notified operators of possible consequences and corrective actions.
