Incident Overview
A pilot executed a gear-up landing after becoming distracted while entering the traffic pattern. The pilot believed he had completed the GUMP (Gas, Undercarriage, Mixture, Propeller) check on approach, but did not verify that the green gear down light was illuminated or visually confirm that the landing gear was extended. During the landing flare, he realized too late that the gear was not down.
Gear System History and Inspection
The pilot reported that the gear system had a history of problems with the indicator lights and warning horn. Following the incident, the gear and its warning systems were inspected. It was found that after selecting either the up or down position, the GEAR PUMP circuit breaker would open before the cycle completed. When the circuit breaker was reset, the gear continued to its selected position. The green gear indication light illuminated approximately 10 seconds after cycle completion. However, the aural warning horn did not sound immediately and was faint when it did engage.
Additionally, placement of the gear handle in the down position caused the gear to fall from the stowed position regardless of whether the power was on or off. No damage was found to the tire sidewalls, gear struts, or wheels, indicating that the landing gear was fully retracted at touchdown.
Prior Damage
The fuselage was distorted from a prior ground damage incident where the airplane was blown over in high winds while parked. This incident corresponded to the onset of the gear system discrepancies.
Conclusion
The investigation documented the sequence of events and the condition of the gear system, but did not assign a specific probable cause.