What happened
On August 28, 2015, a Viking DHC-6-400, registered JA201D, was performing a scheduled passenger flight from Naha Airport to Aguni Airport. The flight was being conducted as a training session, with the Pilot in Command (PIC) acting as an instructor and the First Officer (FO) acting as a trainee for promotion to PIC.
During the landing phase at Aguni Airport, the aircraft touched down on Runway 19. Immediately following touchdown, the aircraft began to deviate toward the right side of the runway. Despite efforts by the crew to maintain control, the aircraft exited the runway surface, entered a grassy area, and collided with the airport's perimeter fence and lateral groove. The impact caused substantial damage to the aircraft, including deformation of the landing gear and damage to the fuselage and engine. While there were 11 minor injuries among the crew and passengers, no fatalities occurred and there was no fire.
The investigation
The Japan Transport Safety Board (JTSB) examined the flight data recorder (FDR) and cockpit voice recorder (CVARG) to reconstruct the sequence of events. The investigation focused on the cockpit procedures leading up to the touchdown and the mechanical state of the nose wheel steering. Investigators also reviewed the company's training protocols and the proficiency of the crew members involved. The investigation included a functional test of the nose wheel steering mechanism, which was performed by the aircraft manufacturer under the supervision of Canadian authorities.
Findings
Investigation findings revealed that the aircraft touched down with the nose wheel already deflected to the right. This deviation was primarily caused by a failure to follow standard operating procedures; specifically, the Pilot Flying (PF) neglected to perform the required checklist, and the Pilot Monitoring (PM) failed to properly supervise the process or provide necessary corrections.
Furthermore, the crew's ability to recover from the initial deflection was compromised by a lack of technical knowledge. The First Officer possessed inadequate understanding of the aircraft's systems, which prevented him from recognizing or reacting to the causes of the steering deflection. The company's oversight of ground and flight training was also identified as a contributing factor, as it had not properly ensured that the necessary technical knowledge was established prior to route training.