What happened
On 19 July 2008, an S-92A2 helicopter, registration HL9292, was performing a flight mission to transport passengers from the Cheongsim International Hospital Heliport to Jamsil Heliport. During the approach to the hospital helipad, the aircraft entered a cloud layer that obscured the landing site. The pilot attempted a go-around; however, the aircraft lost control and struck trees on the slopes of Janglak Mountain in Gapyeong-un, Gyeonggi-do. A fire erupted immediately upon impact, resulting in the total destruction of the aircraft. Of the 16 people on board, six sustained serious injuries and 10 suffered minor injuries.
The investigation
The ARAIB investigation examined the flight crew's actions, the meteorological conditions, and the operational management of the aircraft. Investigators reviewed the flight data, cockpit voice recordings, and the maintenance history of the rotorcraft. The probe also looked into the organizational oversight provided by the operator, Tong-il Aviation, and the safety protocols regarding passenger briefings and emergency equipment. The investigation noted that the aircraft was operating under visual flight rules despite weather conditions influenced by a typhoon that were unsuitable for such operations.
Findings
- The primary cause of the accident was that the flight crew attempted an unreasonable high-speed landing in autopilot mode despite being unable to visually identify the helipad due to cloud cover, subsequently failing to maintain proper flight attitude during the go-around.
- Contributing factors included the decision to proceed with the mission in variable, poor weather conditions.
- The co-pilot failed to provide necessary advice or intervention regarding the flight mission, the approach, or the captain's actions.
- The captain failed to take effective defensive action when experiencing vertigo during the loss of flight attitude.
- The operator, Tong-il Aviation, did not provide sufficient operational support, such as weather trend analysis, and failed to implement adequate Cockpit Resource Management (CRM) training.
- The aircraft lacked the required EGPWS specifications as outlined in the Minimum Equipment List (MMEL).
- Safety deficiencies were noted in the cabin, including improperly labeled and remodeled emergency exits that were difficult to operate, and a lack of adequate passenger safety briefings.