What happened
On February 5, 2018, at approximately 23:48, a UH-60M helicopter, registration NA-706, operated by the National Airborne Service Corps, crashed into the sea off the coast of Lanyu. The aircraft was performing a medical evacuation mission, transporting a patient, a family member, a nurse, and a crew of three (pilot, co-pilot, and crew chief) from Lanyu Airport to Fengnyan Airport in Taitung.
Approximately 81 seconds after departing Lanyu Airport, the aircraft lost contact with air traffic control, and its radar signature disappeared from screens. Following an extensive search, wreckage was located by a remotely operated underwater vehicle on March 5, at a depth of approximately 1,000 meters, about 2 nautical miles west of Lanyu Airport. The wreckage analysis revealed that the cockpit and tail section were missing. The accident resulted in two fatalities and left four persons missing.
The investigation
The Taiwan Transportation Safety Board (TTSB) conducted an investigation into the crash, examining flight data recorder (FDR) parameters, cockpit voice recorder (CVR) transcripts, and meteorological simulations. The investigation included analyzing the aircraft's performance during the takeoff phase, the impact of environmental conditions, and the adequacy of the operator's training and operational procedures.
Numerical weather modeling (WRF) was utilized to simulate the atmospheric conditions at the time of the accident. The investigation also reviewed the operator's standard operating procedures (SOPs), training programs for the transition to the advanced UH-60M model, and the adequacy of crew resource management (CRM) training.