Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 5; Flight Crew Total 780; Flight Crew Type 80
Distraction; Workload
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Gear Up Landing
Aircraft Aircraft Damaged
Aircraft; Human Factors
Following standard briefing from flight service; system checks; and run-up; departed and initiated climb to the northwest. As I climbed engine began running rough. I changed fuel mixture and switched fuel tanks. Engine continued to run rough and produce only partial power. I decided to return to airport. On short final I set flaps and adjusted trim to landing configuration. As I approached touchdown; I realized gear-up warning alarm was sounding. I moved landing gear lever to down position. However; it was too late for gear to fully extend and plane touched down on runway and landed with gear up. Notified UNICOM that I landed gear-up on runway and that there were no injuries. I shut down all systems on the plane and exited. At this time the cause of the engine problem is unknown. One possible cause is that an injector became plugged causing the partial power. The primary cause of the 'gear-up' landing is not following landing checklist under all landing conditions.
M20E pilot reported landing gear-up because of distractions dealing with an engine problem.