What happened
Approximately 45 minutes into the flight, the left engine of the aircraft began to sputter. The pilot attempted to restart the engine, but when the restart failed, he secured the engine and diverted toward an alternate airport.
During the approach, the pilot attempted to lower the landing gear by moving the handle to the down position. When the gear failed to extend, he utilized the primary emergency system via a hand pump. Following the failure of the hand pump, the pilot activated the secondary emergency extension system by pulling the CO2 blow down tank ring. Although the CO2 tank discharged, only the right main landing gear extended. Due to the significant drag caused by the partially extended gear, the pilot determined the airport could not be reached and performed a forced landing in a rough, open field.
The investigation
The investigation focused on the engine failure and the landing gear malfunction. While recovery personnel found that the fuel cells were not breached and no fuel was visible on the ground, a discrepancy in fuel levels was noted. Investigators recovered 15 gallons of fuel from each of the right wing's outboard and inboard tanks, and 30 gallons were drained from the left wing outboard tank; however, no fuel was found in the left wing inboard tank.
Mechanical examination of the left engine, airframe, and landing gear revealed no internal mechanical discrepancies. The fuel injector manifold was disassembled and found to be empty, and no fuel was present in the lines leading from the left wing to the engine. Regarding the emergency systems, investigators noted that the emergency gear handle had been pulled out approximately two inches but was not fully extended, though the CO2 system extension ring appeared to have been pulled.
Findings
- The pilot's attempt to use the emergency landing gear systems was complicated by the fact that the left engine failure disabled the hydraulic pump, as the single system pump is mounted on the left engine.
- Fuel starvation or lack of fuel delivery to the left engine was indicated by the empty fuel lines and empty fuel injector manifold.
- The pilot was not injured during the forced landing.