Event Description
During cruise flight, the first officer reported that both propeller secondary low pitch stop (SLPS) lights illuminated. The right SLPS light illuminated first, followed by the left approximately one minute later. The SLPS system prevented both propellers from going below the low pitch hydraulic mechanical stop. Emergency procedures to correct the condition were ineffective. At some point during the flight, the right propeller feathered. The first officer reported that while operating single engine, they experienced a problem with the propeller governor.
Decision and Approach
The flight proceeded direct to an airport with short runways approximately 3.2 nautical miles (nm) northwest of their present position, rather than to an air carrier airport located 8.5 nm away. The captain entered a close-in right base to runway 35, which was 2,688 feet long. The aircraft was flying at 155 knots, which was 51 knots above single engine reference speed. The captain turned onto final approach with the landing gear and flaps retracted, but overshot the runway.
Crash and Post-Crash Fire
The airplane contacted a taxiway near the departure end of the intended runway, then collided with several obstacles before coming to rest at a house located past the departure end of runway 35. A post-crash fire consumed the cockpit, cabin, and sections of both wings.
Post-Accident Examination
Post-accident examination of the airframe, engines, and propellers revealed no evidence of preimpact failure or malfunction. No determination was made as to the reason for the annunciation of both SLPS lights.
Probable Cause
The probable cause is the poor in-flight planning decision by the captain for his failure to establish the airplane on a stabilized approach for a forced landing, resulting in the airplane landing on a taxiway near the departure end of the runway. Contributing to the accident were the failure or malfunction of the primary hydraulic low pitch stop of both propellers for undetermined reasons, the excessive approach airspeed, and the failure of the captain to align the airplane with the runway for the forced landing.