What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
The pilot took the aircraft up for a flight to check the operation of the electric propeller control. The pilot kept the flight in the local area and was only able to control the RPM using the throttle. When the pilot entered the pattern he was controlling the RPM with throttle and noticed a fluctuation of the oil pressure. Because of the oil pressure and propeller control issues the pilot was distracted and forgot to lower the landing gear. The aircraft landed on its belly and sustained minor damage to the propeller, landing gear doors, flaps and the belly of the aircraft.
As the FAA filed it
THE PILOT TOOK THE AIRCRAFT UP FOR A FLIGHT TO CHECK THE OPERATION OF THE ELECTRIC PROPELLER CONTROL. THE PILOT KEPT THE FLIGHT IN THE LOCAL AREA AND WAS ONLY ABLE TO CONTROL THE RPM USING THE THROTTLE. WHEN THE PILOT ENTERED THE PATTERN HE WAS CONTROLLING THE RPM WITH THROTTLE AND NOTICED A FLUCTUATION OF THE OIL PRESSURE. BECAUSE OF THE OIL PRESSURE AND PROPELLER CONTROL ISSUES THE PILOT WAS DISTRACTED AND FORGOT TO LOWER THE LANDING GEAR. THE AIRCRAFT LANDED ON ITS BELLY AND SUSTAINED MINOR DAMAGE TO THE PROPELLER, LANDING GEAR DOORS, FLAPS AND THE BELLY OF THE AIRCRAFT.