GE and Pratt & Whitney find themselves impacted by inclusions and/or contamination of the metal powders they use in the manufacturing of the major parts constituting their turbojet engines. GE recently announced that the GE90 is subject to an airworthiness directive. Pratt & Whitney is forced to inspect no less than 1,200 turbojets which could be impacted and which are currently in service, produced between 2015 and 2021.
Engine manufacturers victims of metal powders
GE was first impacted and now Pratt & Whitney is affected. In both cases, the engine manufacturers were victims of inclusions or “rare conditions in the metal powder used to manufacture certain engine parts”, as RTX (formerly Raytheon Technologies) declared during the dedicated press conference. to the group’s financial results, explaining the case of Pratt & Whitney.
GE affected on the GE90
The first “officially” affected was therefore GE, through the GE90 which powers the Boeing 777. The engine manufacturer announced that it would have to apply an airworthiness directive, after discovering metal inclusions (more precisely iron) on the GE90 . The FAA mentions that GE informed the latter of the “detection of an inclusion (of iron) in a turbine disk made from the same powdered metal material used to manufacture certain parts of the high pressure turbine (HPT )”. These include stage 1 HPT discs, stage 2 HPT discs, forward HPT rotor seals, inter-stage HPT seals and stage 7 through 9 compressor rotors for GE90 engines . Some of these elements will need to be replaced in order for airlines to comply with the airworthiness directive. The FAA warned that if the situation was not corrected, it could lead to a “uncontrolled release of debris, engine and aircraft damage“, or what is called uncontained damage with the potential risks that this implies.
At least one precedent with the V2500
At Pratt & Whitney, the recall of GTFs – because the engine manufacturer has no other choice than to carry out an inspection – aims to detect microscopic cracks linked to contamination of metal powders, with the same effects ultimately. Before the GTF, other turbojets were affected, notably the V2500, more precisely a V2533-A5 which powered a Vietnam Airlines A321ceo. The aircraft suffered a high pressure turbine (HPT) first stage disc failure which resulted in aborted takeoff at Ho Chi Minh City-Tan Son Nhat Airport in Vietnam. The investigation determined that the cause of the burst was contamination in the metal powder used in the manufacture of high-pressure turbine disks. Following this event, the FAA issued an Emergency Airworthiness Directive on March 21, 2020, requiring the removal from service of affected HPT first stage discs installed on certain IAE V2500 engine models.
GTFs produced between 2015 and 2021
For Pratt & Whitney, the problem – in the same way as the GE90 – affects planes in service with airlines, more precisely those which were produced between 2015 and 2021. Around 1,200 engines will have to be returned and inspected over the next year – 200 by the end of the summer, followed by 1,000 more before September 2024. For the engine manufacturer, this size problem – because it will be necessary to put your hand in your pocket, freed from problems linked to inspections- comes at a time when most of the problems seemed to have been resolved.
