History of Flight
On October 12, 2011, at about 1334 eastern daylight time, a Socata TBM 700, registration N37SV, executed a forced landing on the Florida Turnpike near Hollywood, Florida, after experiencing a total loss of engine power. The flight was a maintenance test flight following a 600-hour and annual inspection, operating under instrument flight rules from North Perry Airport (HWO). The airline transport pilot and a pilot-rated passenger sustained minor injuries; no ground injuries were reported.
According to the right-seat occupant, fuel was added to balance the tanks before departure. The pilot reported that due to the fuel load, he could not visually check the levels but relied on cockpit indications showing approximately 105 gallons in the left tank and 108 gallons in the right tank. The fuel selector was in the "auto" position. During climb to flight level 280, the crew received a "Fuel Low R" amber caution, attributed to a sensor malfunction, and later a "Fuel Unbalance" caution, prompting manual selection to the right tank. Similar alerts occurred during descent, and the pilot switched the fuel selector accordingly.
The flight executed an ILS approach at Opa-Locka Executive Airport with a low approach, then proceeded visually to HWO. While on downwind, another "Fuel Unbalance" caution appeared; the pilot selected the right tank manually. On final approach at about 800 feet, a red "Fuel Press" warning illuminated. Despite moving the auxiliary fuel boost pump to "On" and switching the selector to the left tank, engine power did not return. The pilot performed an unsuccessful airstart and then executed a forced landing on the turnpike, retracting the landing gear to shorten the landing distance.
Aircraft Information
The airplane, manufactured in 2008 by EADS Socata, was powered by a Pratt & Whitney Canada PT6A-66D engine and had a total usable fuel capacity of 292 gallons in two wet wings. Fuel gauging used capacitance probes with low fuel sensors that triggered caution messages when under about 9 gallons. The G1000 recorded fuel data during the flight, showing fluctuating indications: left fuel decreased steadily when selected, while right fuel varied with increases noted. At the end of recorded data, left fuel was about 62 gallons and right about 60 gallons.
Maintenance records showed a prior repair of the right fuel quantity harness in August 2010. During the 600-hour inspection, fuel was drained from the right wing due to leaks; after repairs, fuel was returned, but subsequent G1000 readings showed unexplained increases without refueling. No maintenance was performed to investigate these discrepancies.
Post-Accident Examination
The NTSB inspected the wreckage after recovery. The cockpit showed the auxiliary boost pump in "Auto", the manual selector in "Off", and the overhead fuel selector in "Manual". Both wings sustained breaches but no obstructions inside the tanks. Fuel system testing revealed fluctuations: with empty wings connected, the G1000 initially displayed 108 gallons in the left tank, which dropped to 29 gallons over 10 minutes. Examination of fuel probes, sensors, and harnesses found no preimpact failure in most components. However, the right fuel gauge harness exhibited an intermittent connection: resistance varied from several thousand ohms to over 1 million ohms when moved, and X-ray analysis revealed an improperly soldered shielded wire near the P60 connector. Testing of an exemplar harness with the same defect showed maximum fuel quantity indication on a dry tank.
The engine was removed and tested for over 2.5 hours at various power settings; all parameters except inter-turbine temperature were within repair limits. The propeller blades were bent aft but no engine anomalies were identified.
Findings
The investigation identified a manufacturing defect in the right fuel gauge harness that caused erroneous fuel quantity indications. The intermittent high-resistance connection led to inaccurate readings, contributing to the crew's misunderstanding of actual fuel state. The engine failure likely resulted from fuel starvation due to mismanagement of fuel tank selection based on faulty gauge indications.