Muan Airport plane accident raises possibility of defect in complex equipment...Estimation of engine/hydraulic system simultaneous abnormalities

Photo by: BBC News Korea

Regarding the cause of the Muan International Airport plane accident that occurred in late December, there is a possibility that complex device defects, not simple pilot mistakes, are the main cause. The Aviation Railroad Accident Investigation Committee (ARAIB) is focusing on whether the engine of the accident aircraft and the hydraulic system failed.

At the time of the accident, the Jeju Air passenger plane reportedly approached the runway in an abnormal position as the engine power became unstable during landing. Since then, the landing gear (landing device) has not been deployed properly just before landing, and an operation error has also occurred in the process of the pilot manually unloading the equipment.

Experts are paying attention to the possibility that this phenomenon is not a single equipment defect, but rather a chain system failure leading to engine failure → hydraulic pump failure → landing gear failure. In fact, since the hydraulic system of an aircraft operates based on the rotational force of the engine, if the engine stops, the landing gear and steering system can be affected.

An aviation maintenance expert (anonymous) said, "At that time, there was a situation in which abnormal signals were repeatedly detected in the internal vibration and pressure sensor of the plane's engine," adding, "The maintenance record confirms that the engine has been replaced eight times this year alone." He added, "This repeated replacement is not just a wear, but suggests structural fatigue cracks or possible manufacturing defects."

In addition, according to some reports, CFM International, the manufacturer of the aircraft engine, was already aware of the problem of cracking compressor blades on similar models. The industry points out that this accident requires verification of the transparency of the engine manufacturer's quality management system and maintenance history.

The possibility of failure to deploy the landing gear is also subject to investigation. The possibility cannot be ruled out that the landing gear sensor or external wiring was damaged due to the Bird Strike during landing. Some analysts say that neither automatic nor manual operation of the landing gear was possible due to a combination of the hydraulic and electrical systems.

Experts say the accident is not just an equipment failure, but a warning of interdependence between systems. An official from the Korea Aerospace Research Institute said, "Hyundai Airliners are closely connected to several systems, so more than one part can lead to the collapse of the entire system," and stressed, "In order to prevent accidents, an integrated data-based diagnostic system is needed beyond a single device inspection."

Investigation authorities are currently analyzing black boxes and flight data recorders, and metal fatigue and pressure loss of internal parts of the engine are known to be key investigation items. The final analysis results will be released in the first half of next year.