What happened
The aircraft touched down on the runway with the landing gear retracted. Following the event, investigators examined the aircraft systems to determine why the gear did not extend or lock properly during the approach and landing phase.
The investigation
Mechanical inspection of the landing gear system revealed no malfunction that would have prevented normal operation. A specific retraction test confirmed that the mechanical components functioned as designed. However, electrical diagnostics showed that the warning horn failed to operate when it should have.
Upon checking the cockpit prior to removing the aircraft from the runway, investigators discovered that the landing gear circuit breaker had popped. This electrical failure prevented the warning system from alerting the pilot to the unsafe gear configuration.