Accident Overview
On March 3, 2021, about 1745 Pacific daylight time, a Cessna 172G, registration N4456L, was substantially damaged in an accident near Sisters Eagle Air Airport (6K5) in Sisters, Oregon. The pilot sustained serious injuries and the passenger sustained minor injuries. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Flight Sequence
According to the pilot, she performed a preflight inspection and noted 16 to 17 gallons of fuel on board. The engine run-up was normal, and the flight proceeded to Bend Municipal Airport (BDN) in Bend, Oregon, where she executed three touch-and-go landings. Subsequently, she flew to Redmond Municipal Airport (RDM) for one touch-and-go landing before returning to 6K5. During the en route portion to RDM, the pilot leaned the mixture; she did not adjust it again until after the engine power loss. She reported that she departed with the fuel selector in the BOTH position and switched to the left fuel tank upon reaching cruise altitude. After departing RDM, she switched the selector to the right fuel tank for the remainder of the flight.
Engine Power Loss and Forced Landing
On final approach to land at 6K5, the pilot performed a forward slip with the engine power at idle and the flaps retracted. She described the approach as fast, and the airplane bounced on the runway. She applied a quick burst of throttle in an attempt to recover but was unsuccessful, so she elected to abort the landing. The pilot reported applying nearly full power, removing carburetor heat, then adding the remaining power, at which point the engine lost all power at an altitude of about 150 feet above ground level. She attempted to restart the engine by increasing the mixture control to full rich, cycling the carburetor heat, and turning the magnetos. She then readjusted the mixture control but could not restart the engine. Notably, she did not switch the fuel tank selector during the restart attempts. Unable to regain engine power, she initiated a forced landing to an open field. The airplane came to rest in a nose-down attitude, sustaining substantial damage to the empennage, both wings, and the forward fuselage.
Postaccident Examination
A Federal Aviation Administration inspector reported that after the accident, the right-wing fuel tank was nearly empty, while the left-wing fuel tank contained fuel. The gascolator contained very little fuel. A postaccident examination of the engine found no mechanical anomalies. Valve train continuity was verified, and suction and compression were obtained on each cylinder when the propeller was rotated by hand. Both magnetos produced spark when tested. Spark plugs exhibited normal wear signatures. The carburetor was partially torn from its mount but remained intact and clear of debris. The throttle cable and mixture linkage travel were normal, and the carburetor heat valve was closed. Fuel present in the carburetor was clean and tested free of water. The Cessna 172 Owner’s Manual before-landing checklist specifies that the mixture control should be in the rich position for landing and the fuel selector should be in the BOTH ON position. Additionally, the fuel selector was placarded with "BOTH TANKS ON FOR TAKEOFF & LANDING." The Cessna Pilot Safety and Warning Supplements contain a warning about fuel flow interruption during maneuvers that may uncover the fuel tank outlet, stating that pilots can prevent this by having adequate fuel in the selected tank and avoiding prolonged uncoordinated flight or sideslips.