Accident Overview
On February 27, 2016, about 1125 eastern standard time, a Beech model V35 single-engine airplane, registration N2714T, was substantially damaged during a forced landing on Interstate I65 near Seymour, Indiana. The private pilot and his two passengers were not injured. The airplane was operated under 14 CFR Part 91 for a personal flight. Day visual meteorological conditions prevailed.
Flight Details
The flight departed Indianapolis Metropolitan Airport (UMP) about 1045, with an intended destination of Bowman Field Airport (LOU) in Louisville, Kentucky. The pilot estimated the airplane had about 40 gallons of fuel, with the right main tank containing about 30 gallons and the left main about 10 gallons. Both outboard tip tanks contained only residual fuel. The flight received VFR flight following from air traffic control.
Engine Malfunction
After reaching a cruise altitude of 5,500 feet, the pilot switched from the right main fuel tank to the left main tank. About 10 minutes later, he switched back to the right main as he prepared for descent. Approximately 3 minutes after returning to the right main, the engine began to run roughly. The pilot switched back to the left main, increased mixture to full rich, and turned on the high-boost auxiliary fuel pump. The engine continued to run roughly with occasional power surges and backfires. He then selected the low-boost pump and switched back to the right main, which held more fuel. Engine operation briefly improved for 15-20 seconds before resuming partial power with surges. The pilot cycled through various fuel tanks, including the right wingtip with residual fuel, ultimately settling on the right main tank for the remainder.
Forced Landing
Air traffic control provided vectors toward Freeman Municipal Airport (SER) near Seymour, but the pilot determined the airplane lacked altitude to reach it. He executed a forced landing on the southbound lanes of I-65 near mile marker 42. The airplane touched down at about 80 knots indicated airspeed with flaps fully extended. After touchdown, the pilot maneuvered to avoid another vehicle, entering the grass median. The left wing impacted a grass embankment. The pilot then moved the mixture to idle-cutoff and evacuated.
Postaccident Inspection
The airplane was recovered to a hangar at SER. A postaccident inspection by an FAA Airworthiness Inspector found substantial damage to the left wing aft spar. Fuel quantity indicators showed the right main tank about 3/4 full (about 30 gallons) and the left main about 1/4 full. Nine gallons of fuel were drained from the left main tank. Both auxiliary fuel pumps functioned normally when powered.
An operational engine test run was conducted by the pilot under FAA supervision. The engine started and warmed up normally, though idle speed dropped 100-200 rpm and it ran rough for a few minutes. A pretakeoff run-up, including magneto check and propeller cycling, showed no anomalies. The pilot noted a slight hesitation when increasing to maximum static rpm, but the engine achieved full rpm. During cruise power, alternating between main tanks caused no interruption. When the fuel selector was placed between the right and left main positions, the engine ran normally for about 30 seconds before losing power and backfiring from fuel starvation. Normal operation resumed immediately after reselecting the right main tank. The test run did not reveal any anomalies that would have precluded normal operation of the Continental TSIO-520-DB7B engine.
Additional Information
The airplane was manufactured with a turbocharged engine, a separate low-boost auxiliary fuel pump, and wingtip fuel tanks under supplemental type certificates, and is often referred to as a Beech V35TC. The original auxiliary fuel pump was designated "high-boost" after the low-boost pump was installed. The airplane was placarded against takeoffs with less than 13 gallons in each main tank to prevent fuel outlet unporting during takeoff. The pilot's manual for the V35TC states that during engine power loss, the auxiliary fuel pump should be used momentarily; if operation does not improve, the pump should be turned off. The flight manual supplement for the turbocharged engine stipulates that if a fuel tank is depleted, the low-boost pump should be used while switching tanks, then turned off. It cautions that operating with the high-boost pump on with a functioning engine-driven pump can produce an over-rich mixture and partial or total power loss.