Accident Sequence
The private pilot was conducting an instrument flight rules (IFR) cross-country flight in visual meteorological conditions (VMC). Witnesses near the accident site observed the airplane at low altitude trailing smoke. The airplane was flying in a downwind and base type pattern toward an open area, where it crashed. Witnesses reported that the airplane impacted terrain while in a steep left-hand turn and was fully engulfed by fire after impact.
Pilot Report
Shortly before the crash, the pilot radioed that he was experiencing engine problems and that the airplane was on fire.
Wreckage Examination
Examination of the wreckage revealed a black, oil-like substance along the leading edge of the right stabilizer. Heavy dark soot and oil deposits were found on the bottom of the engine, beginning below the number six cylinder in the area of the waste gate controller and extending to the rear of the engine near the accessory case. The turbocharger waste gate is actuated by oil pressure supplied through an inlet oil supply hose and an oil return hose. Both hoses were Aeroquip metal-braided nonfire shielded hoses, covered in dark soot and an oil-like substance. Additionally, both oil lines appeared thermally damaged.
Component Testing
The waste gate actuator inlet line was pressure tested, and a leak was noted between the hose collar and the B-nut on the actuator side. The oil return line was pressure tested, and multiple leaks were found along a 14-inch section of the hose. When the steel braided outer cover was removed, the inside rubber hose was found to be deteriorated and oil soaked.
Maintenance Records
A review of the maintenance logbook disclosed no specific entry related to the installation of the nonfire shielded Aeroquip hoses. A representative from the engine manufacturer stated that the steel braided Aeroquip hoses found on the accident airplane were not supplied by the engine manufacturer.
Probable Cause
Given the condition of the turbo charger oil lines and fittings, it is probable that a high pressure oil leak sprayed oil onto the hot engine and started an in-flight fire.