Primary finding
Probable cause
The pilot's improper reduction of the fuel mixture while the airplane was descending on the final leg of the traffic pattern, which resulted in a total loss of engine power and subsequent aerodynamic stall.
Investigator assessment
Analysis narrative
According to the commercial pilot, while the airplane was descending on the final leg of the traffic pattern after the personal flight, he reduced the fuel mixture, and the engine then lost total power. The pilot was unable to regain engine power, and the airplane entered an aerodynamic stall and subsequently impacted the ground, which resulted in substantial damage to the wings, vertical stabilizer, and fuselage. A postaccident examination of the airplane revealed no preaccident mechanical malfunctions that would have precluded normal operation. The Engine Operator's Manual stated that the mixture must be in the "full rich" position during the descent. It is likely that the pilot's reduction of the fuel mixture during the descent resulted in the loss of engine power.
Source record
Factual narrative
On May 29, 2015, about 1300 eastern daylight time, a Luscombe 8A, N2009B, impacted terrain prior to the runway at Harford County Airport (0W3), Churchville, Maryland. The commercial pilot sustained minor injuries. The airplane sustained substantial damage to the wings, vertical stabilizer, and fuselage. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. The airplane was registered to, and operated by, a private individual under the provisions of Title 14 Code of Federal Regulations Part 91.According to two witnesses, the airplane flew over the south side of the airport and "sounded like" it lost engine power. The airplane was observed descending on a right downwind leg for runway 19 and continued to descend while on the right base leg of the traffic pattern. The witness then lost sight of the airplane. In an interview with a Federal Aviation Administration inspector, the pilot stated that while descending on approach to runway 19, he decreased the engine power and turned onto the final leg of the traffic pattern. He reduced the mixture, the airplane lost total engine power, the pilot could not regain engine power, and the airplane "entered a stall" prior to impacting the ground. During the accident sequence, the airplane impacted terrain prior to runway 19, nosed over, and came to rest inverted, which resulted in substantial damage to the wing spar and fuselage. A postaccident examination of the airframe and engine revealed that there were no mechanical malfunctions or anomalies with the airplane prior to the accident that would have precluded normal operation. Despite multiple attempts, a completed Pilot/Operator Aircraft Accident/Incident Report (NTSB form 6120.1/2) was not received for this accident. According to the engine operator's manual, "the mixture control must be in 'FULL RICH' during descent."