WPR16LA039

The private pilot reported that the accident flight was the airplane's first flight after being painted. After completing a preflight inspection, the pilot started the engine and observed a decrease in power. He leaned the mixture slightly, and the engine rpm returned to normal idle speed. The pilot reported that during the engine run-up, he noticed that the engine had a delayed response when he increased the throttle, but that the run-up otherwise revealed no anomalies. The pilot stated that the takeoff roll took longer than expected, and after lifting off near the end of the runway, the airplane climbed more slowly than normal. The pilot stated that during the initial climb, engine power had decreased to 2,000 rpm. As the airplane reached about 100 ft above ground level, the engine was producing about 1,800 rpm and could not maintain a climb. The pilot elected to continue straight ahead rather than return to the runway, and the airplane subsequently descended into trees. A postaccident examination revealed no anomalies with the airframe or engine that would have precluded normal operation. The reason for the partial loss of engine power was not determined.

On December 14, 2015, about 1341 Pacific standard time, a Mooney M20E, N5863Q, experienced a partial loss of engine power during takeoff from the Corona Municipal airport (AJO), Corona, California. The pilot (sole occupant) was uninjured and the airplane sustained substantial damage. The airplane was registered to, and operated by, the pilot under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal flight and no flight plan was filed. The airplane was destined for the Chino Airport (CNO), Chino, California. The pilot reported that this was the first flight after the airplane underwent a new paint application. After a thorough preflight, the pilot started the airplane and he observed the RPMs drop a little. He leaned the mixture slightly and the RPMs returned to normal idle speed. He taxied the airplane to the run-up area and conducted a run-up. As he increased the engine's RPMs to 1,800 for a magneto check, he observed a slight delay in the RPM increase, but otherwise all indications were normal. The pilot positioned the airplane onto the runway and added full power. He observed the RPMs increase slowly to 2,400 RPM. Halfway down the runway the airplane was not at lift off speed, however, the RPMs were above 2,400 RPM. The airplane reached 80 knots and lifted off the ground near the end of the runway; the airplane climbed slower than normal. The pilot leveled the airplane to gain airspeed, but he observed that the engine RPM dropped to 2,000 RPM. Expecting to conduct an emergency landing the pilot left the landing gear down and the fuel pump on, he also ensured the throttle and mixture were full rich. The RPMs decreased to 1,800 and at about 100 feet above the ground, the airplane started to descend into the trees at the end of the runway. The left wing impacted a tree top and the airplane descended abruptly into the ground below. A postaccident examination of the airframe and engine by a Federal Aviation Administration Inspector and a mechanic did not reveal any anomalies. Flight control continuity was established, as well as, continuity to the throttle, mixture, and propeller controls. The fuel system was intact and fuel flowed freely through it. The valve covers were removed; the intake and exhaust valves sustained no abnormal wear signatures. The oil filter was removed and disassembled; no debris or contaminates were noted. The spark plugs were removed and displayed "normal" wear signatures when compared with the Champion "Check-a-plug" chart. The propeller was manually rotated and no binding or grinding was noted within the engine. Thumb compression was established on all cylinders. The magnetos were tested and fired normally.