A claim has been raised that CFMI was already aware in advance of a structural defect in the CFM56 engine, identified as the cause of the Jeju Air passenger plane (airframe number HL8088) accident at Muan Airport in Dec. last year.
According to the office of lawmaker Kim Eun-hye of the National Assembly's Land Infrastructure and Transport Committee on the 29th, CFMI internally warned in a Service Bulletin issued in April 2023 that "cracks in the high-pressure turbine blade can cause overall damage." CFMI is an engine manufacturer jointly founded by U.S. GE and Safran.
According to documents obtained by the lawmaker's office, a structural defect that occurred during specific manufacturing and forging processes of the engine was specified as the cause of the damage. While CFMI maintained the position that the engine would be safe as long as the blade replacement interval was observed, the lawmaker's office noted that no measures were taken to fundamentally resolve the defect itself.
The lawmaker's office explained that the defect was first reported after a Jeju Air aircraft (HL8303) bound for Jeju from Kansai Airport in Japan in 2022 returned due to an engine abnormality. The German engine manufacturer MTU, which analyzed the engine failure at the time, raised the possibility of a manufacturing defect, and the lawmaker's office found that CFMI issued the Service Bulletin based on that.
Nevertheless, aircraft operated by Jeju Air equipped with the same engine continued to fly, and the lawmaker's office said the Muan accident aircraft was also fitted with the same model engine.
The Aviation and Railway Accident Investigation Board sent the engine to France for detailed analysis but announced in its interim findings that "no defect was found." It then prepared an official announcement stating that "the engine shut down due to a pilot error," but the release has been put on hold due to opposition from the bereaved families.
Kim Eun-hye said, "It is inappropriate to make a definitive judgment when even the manufacturer recognized the defect," adding, "The investigation committee should keep all possibilities open and verify them."