In December last year, the Jeju Air passenger jet that caused an accident with 179 deaths at Muan International Airport in South Jeolla Province was found to have had its engine parts replaced eight times last year. The engine (CFM56) used in the crashed plane was also judged to have a "manufacturing defect" by a German aircraft engine maker in 2023.
According to the "Muan crash aircraft (HL8088) engine inspection records" that Rep. Kim Eun-hye of the People Power Party on the National Assembly's Land, Infrastructure and Transport Committee received from the Ministry of Land, Infrastructure and Transport on the 13th, the jet experienced 10 cases of failure, damage, or abnormal messages in 2023–2024 and changed parts 10 times. The failure list also included the electronic engine control (EEC), which handles braking power during landing.
In particular, eight failures occurred last year, all only on the right engine. In an investigation by the Ministry of Land, Infrastructure and Transport's Aviation and Railway Accident Investigation Board immediately after last year's Muan Airport crash, it was also found that, of the two engines, the right engine suffered severe damage.
In Nov. 2022, a Jeju Air passenger jet (HL8303) bound for Jeju from Kansai, Japan, made a return due to an engine defect, and it turned out that this aircraft's engine was the same as the engine on the Muan Airport crash aircraft. The engine was made by CFMI, a U.S.-France joint venture.
Jeju Air entrusted repair of the CFM56 engine to MTU, a German engine manufacturer, and MTU notified the result that "a defect that occurred during a special process in forging during engine manufacturing was the main cause and the engine interior was damaged." In other words, the problem arose because the strength of parts weakened during the engine manufacturing process.
In Jul., the accident investigation board tried to issue an announcement to the effect that "the engine was shut down incorrectly due to the pilot's confusion," but it was scrapped due to opposition from the bereaved families. The board explained to the families that the pilot shut down the left engine instead of the right engine, which had severe damage, and then also shut down the right engine's power unit. At the time, criticism also arose that the board was excluding the possibilities of an engine parts defect or a shutdown caused by an external impact.
An aviation industry official said, "The engine in question has sold more than about 15,000 units worldwide and is a product used by most airlines. The engine that Jeju Air sent to Germany has already been scrapped."