Incident Overview
A pilot, who was also an airplane mechanic, was conducting the first flight after replacing both engines' propeller assemblies as part of preparing the aircraft for export. During the approach and landing, the airplane touched down on the runway with the landing gear retracted, causing the propeller blades to contact the runway surface.
Flight Sequence
On departure, while focusing on synchronizing the engine speeds, the pilot noticed a slight smell of electrical burning in the cockpit. The odor became stronger on the downwind leg. The pilot then expedited the base leg and, believing he had extended the landing gear, continued the approach. During the landing flare, the stall warning horn sounded, and the propeller blades struck the runway.
Post-Accident Examination
Following the incident, a Federal Aviation Administration coordinator conducted an examination of the airplane. The aircraft was placed on jacks, and the landing gear system was tested. The landing gear was completely cycled three times, with positive indications of both up and down positions via the gear up and down indicator lights and the mechanical indicator. Additionally, the starter vibrator was found discolored and charred, indicating an overheated condition.
Conclusion
The pilot's distraction due to the electrical burning smell and his belief that the landing gear was extended led to the gear-up landing. The examination confirmed that the landing gear system was functioning correctly after the incident.