Accident Overview
On May 23, 2010, about 1600 Pacific daylight time, a Socata TBM-700, registration N750AB, experienced a loss of engine power during cruise flight. The pilot conducted an emergency landing on runway 33 at Lost Hills – Kern County Airport (L84), Lost Hills, California. The airplane overran the runway, and the nose landing gear was sheared off, causing the airplane to come to rest on its nose. The pilot/owner and four passengers were not injured; the airplane sustained substantial damage to the wings and fuselage. Visual meteorological conditions prevailed for the personal flight operating under 14 CFR Part 91.
Flight History
The flight departed San Luis Obispo Airport (SBP) about 1530, with a planned destination of Fresno-Yosemite Airport (FAT). No flight plan had been filed, but the pilot had been receiving flight-following. Earlier that day, the pilot had topped off with fuel before departing FAT, totaling 282 gallons on board. After landing at SBP about 1100, the pilot and family visited a local university campus before returning for the return flight.
Pilot Actions and Events
During the climb after takeoff, the pilot reported that the rudder deflected fully to the left, prompting him to discontinue the climb at 9,500 feet. He turned off the yaw damper and manually flew the airplane, cycling the autopilot without resolving the issue. Oakland Air Traffic Control Center (OAK ATCT) asked if he needed assistance, which he initially declined. He then initiated a climb to his intended altitude of 13,500 feet, during which the airplane’s avionics failed, including the GPS, followed by a loss of engine power and illumination of the low fuel pressure light for the left fuel tank. He requested vectors to the nearest airport and feathered the propeller while attempting to restart the engine.
The pilot later reported that the slip/skid indication on the pilot’s flight display showed a full right deflection, confirmed by the rudder deflection indicator. After losing engine power, he declared an emergency and asked for vectors, noting that both Garmin units (GNS430 and 530) had temporarily lost power and were rebooting. He made a left base approach for runway 33, landed midfield, and rolled off the end of the runway about 300 feet, shearing the nose landing gear and damaging the left wing and fuselage.
Post-Accident Examination
Retrieval personnel noted the airplane came to rest nose-down. Both wings remained attached; the left flap was extended with no apparent damage. No fuel was recovered from the left fuel tank, while the right wing contained about 90 gallons of fuel. The bottom of the fuselage sustained substantial damage. Inside the cockpit, all circuit breakers were pushed in except the rudder trim circuit breaker, which was partially out. The fuel sequencer was selected to AUTO.
A functional check of the rudder trim and fuel control unit (FCU) was performed. When the autopilot was tested, it operated normally, but the rudder trim indicator showed full deflection to the right. The rudder trim switch did not move the indicator, and no trim motor noise was heard. After pulling and recycling the partially out rudder trim circuit breaker, the system operated normally. A functional test of fuel delivery found no flow restriction to the FCU, but the pressure differential indicator on the fuel filter was extended, indicating the bypass had activated.
Visual inspections of the airframe and engine revealed no mechanical anomalies. The engine was inspected by Pratt & Whitney on June 24, 2010; no mechanical problems were found. The airframe was inspected on July 21, 2010, by the NTSB and Daher-Socata; no mechanical anomalies were noted. The rudder trim actuator was examined by Precilec under BEA supervision; it functionality was normal, though two acceptance test values did not conform to tolerance limits without affecting operation. Pitch, roll, and yaw servos were bench tested and operated normally. The pitch trim circuit breaker was examined and found closed with no damage. The GPS units (Garmin GMX-200, Garmin GDU-620, Bendix/King KCP-220) were examined but no accident-related data was recovered.
The pilot’s operating handbook (POH) specifies total usable fuel of 281.6 gallons and a maximum fuel imbalance of 25 gallons. The fuel automatic selector normally changes tanks every 10 minutes unless a low-level warning light illuminates, then it selects the other tank. The manufacturer’s representative noted that fuel starvation in the lower wing could occur if the airplane was in a crab with a roll angle position, leading to engine shutdown. The pilot stated the POH did not specify cross-control limitations for fuel starvation.