Final Report: Arcing blamed for fire
Hawker Beechcraft 99, Moline, Ill., Feb. 18, 2008–No one was injured during the in-flight fire, which the Safety Board attributed to the arcing of the resistor and silicone-controlled rectifier in the flap control circuit. The pilot of the Suburban Air Freight cargo flight “smelled electrical smoke and saw flames behind the power quadrant,” while descending to land at Quad City International Airport (MLI). He declared an emergency and grabbed the fire extinguisher. By then, the flames and burning smell had subsided, so he continued to MLI.
The lead of a resistor in the flap control circuit contacted a ground lug. It was supposed to be covered by a sleeve. The circuit breaker controlling the circuit, manufactured in 1967, was rated to trip at five amps, but required 17 amps in subsequent tests.