Flight History
On August 28, 2015, at approximately 08:55 JST, a Viking DHC-6-400 registered JA201D, operated by First Flying Co., Ltd., was conducting a passenger transport flight from Naha Airport to Aguni Airport. The flight was operated under Visual Flight Rules. The cockpit crew consisted of a Pilot in Command (PIC) seated in the right seat as Pilot Monitoring (PM) and instructor, and a First Officer (FO) seated in the left seat as Pilot Flying (PF) and trainee for promotion to PIC. There were 14 persons on board: the PIC, the FO, a crewmember, and 12 passengers (including one company employee).
Accident Sequence
According to the flight data recorder (FDR) and cockpit voice recorder (CVR) records, the aircraft took off from Naha Airport at 08:38. During the approach to Aguni Airport, the PF conducted a landing briefing at 08:46, specifying flap 20° and Vref of 77 kt. The aircraft passed the threshold of Runway 19 at 75 kt at 08:54:27. At 08:54:31, wheel touchdown sounds were recorded, followed by tire screeching. The heading was 189°, bank angle 0.5° left, ground speed 76 kt. At 08:54:32, the PIC instructed "Don't brake," repeated at 08:54:36. The heading increased to 195° and ground speed decreased to 62 kt. At 08:54:38, the aircraft began to depart from the right side of the runway. By 08:54:40, it entered the grass area to the right of the runway, with heading 209°, bank angle 0.6° left, and ground speed 49 kt. Collision noise was recorded at 08:54:41.
Damage and Injuries
The aircraft collided with the airport perimeter fence and a lateral groove, resulting in substantial damage. No fire occurred. A crewmember and ten passengers suffered minor injuries.
Investigation Findings
The Japan Transport Safety Board investigated the accident. The PIC stated that the PF had long experience. The PF was responsible for flying, while the PIC monitored and instructed. The investigation noted that the PF forgot to perform the checklist, and the PIC did not properly monitor or point out the omission, leading to a touchdown with the nose wheel deflected to the right. The PF's knowledge of the aircraft system was inadequate, and the company had not properly confirmed the effectiveness of ground school training.