Incident Details
While conducting an NDB approach in instrument meteorological conditions with the landing gear extended, the fire warning light for the right engine illuminated. The flight crew shut down the right engine and initiated a missed approach. However, the landing gear would not retract, and the aircraft was unable to maintain altitude. As the aircraft descended into the top of an overcast layer at approximately 600 feet, the pilots attempted to restart the right engine but were unsuccessful.
The aircraft continued to descend, breaking out below the clouds at an altitude of about 150 to 170 feet. The certified flight instructor (CFI) then executed a landing in an open field. Upon touchdown, the nose gear encountered soft dirt, causing the aircraft to nose over.
Investigation Findings
A post-incident examination revealed that an electrical power jumper wire between two bus bars had become chafed and shorted. The left and right isolation circuit breakers, as well as the bus tie circuit breaker, were found in the tripped (open) position. This electrical failure resulted in a false fire warning indication and prevented the landing gear from being retracted. Additionally, it prevented the restart of the right engine, contributing to the forced landing and subsequent nose-over.