What happened
On July 21, 2013, a privately owned Gulfstream Aerospace AG-5B, registration JA4175, was conducting a familiarization flight from Fukui Airport to Tottori Airport when the pilot reported an engine malfunction. During the flight, the pilot switched the fuel selector valve, after which engine vibrations and a gradual decrease in RPM were noted.
As the aircraft approached Tajima Airport, the pilot requested an emergency landing on runway 19. Due to the deteriorating engine performance and the need to reach the airport quickly, the pilot opted for a direct approach rather than a standard traffic pattern. The aircraft approached the runway at a high speed, estimated by witnesses to be significantly higher than typical approach speeds, and encountered a 15-knot tailwind.
During the landing, the aircraft overshot the runway centerline, oscillating left and right. The aircraft failed to stop within the runway limits, overran the stopway, struck guardrails on a service road, and eventually bounced over the rails into a forested area on a cliff south of the airport. Despite the aircraft being destroyed, the pilot and two passengers escaped without injury.
The investigation
The Japan Transport Safety Board (JTSB) conducted an investigation involving on-site inspections, airframe examinations, and interviews with the pilot, passengers, and witnesses. Investigators analyzed the flight history, engine performance, and the pilot's recent flight experience. The investigation also examined the fuel system, specifically looking into whether foreign substances had obstructed the fuel supply.
Findings
- The primary cause of the accident was the high-speed approach and lack of proper engine power control during the emergency landing, which led to the runway overrun.
- The pilot's inability to manage the situation according to standard procedures was attributed to insufficient recent flight experience and a lack of maintained flight knowledge and skills.
- The aircraft approached the runway with a significant tailwind and at an excessive speed, which prevented a controlled landing within the available runway length.
- A contributing factor to the engine power loss may have been the improper use of sealing tape, which potentially allowed debris to enter the fuel selector valve and obstruct fuel flow, though this could not be definitively proven.
- The pilot's decision to maintain a higher airspeed to prevent altitude loss, rather than transitioning to a maximum gliding speed, contributed to the high-speed touchdown.