Accident Details
On July 27, 2016, at approximately 1645 Pacific daylight time, a Cessna 310B multi-engine airplane, registration N6605B, sustained substantial damage following a loss of control during takeoff at Columbia Airport (O22), Columbia, California. The airline transport pilot and three passengers sustained fatal injuries. The airplane was registered to and operated by the pilot under 14 Code of Federal Regulations Part 91 as a personal cross-country flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was originating at the time of the accident, with an intended destination of Monterey, California.
Witness Observations
A witness working at the air tanker fire base reported that after the airplane lifted off, it was in level flight and drifting left of the runway. The landing gear was down, both engines appeared to be running, and the airplane was "slightly leaning left and drifting hard to the left." The left main landing gear touched down, followed by the left wing impacting the taxiway. The airplane slid left, off the taxiway into a helipad area, and burst into flames.
A second witness observed the airplane climb to about 50 ft, then drift left over the grass between the taxiway and runway. The witness noted it was "obvious that there was something wrong" and that the pilot was "possibly attempting to land on the taxiway." The airplane crashed, came to rest, and caught fire.
A third witness, an air tanker pilot, saw the airplane taxi in front of him and into position for a full-length takeoff on runway 17. He noticed the right engine was shut down, then watched the pilot restart it and begin the takeoff roll about 10 seconds later. He observed the first 200 ft of the takeoff roll, which appeared uneventful.
A fourth witness, about 835 ft west of and perpendicular to the runway centerline, initially saw the airplane 40-50 ft above the runway. He noticed it slow slightly, then saw "the rear landing gear" come up. The nose rose, the airplane veered left (left wing dipped), and it lost altitude, impacting the ground possibly left wing first, then sliding about 50 ft before stopping and erupting into a fireball.
Video recordings from airport building cameras estimated the airplane's ground speed during the last 5 seconds of flight at 71±3 knots.
Aircraft Information
The five-seat, low-wing, retractable-gear airplane, serial number 35705, was manufactured in 1958. It was powered by two fuel-injected Continental IO-470 engines, each equipped with a McCauley three-bladed constant-speed propeller. Maintenance records for the aircraft, engines, and propellers were not located. According to the type certificate data sheet, the only approved engine was a Continental O-470-M, and approved propellers were Hartzell HC82XF-2 or HC-A2XF-2. The FAA supplemental type certificate (STC) database showed STCs for fuel-injected IO-470 engines and Bendix fuel injection systems, but no records of these STCs being installed on the airplane were found. No STC for the McCauley propellers was located.
Meteorological Conditions
At 1655, the weather reporting facility at O22 indicated wind from 290° at 7 knots, visibility 10 statute miles, temperature 40°C, dew point 3°C, and an altimeter setting of 29.92 inches of mercury. Airport elevation was 2,121 ft mean sea level. The calculated density altitude was 5,483 ft.
Wreckage and Impact
The airplane came to rest about 3,775 ft from the start of the takeoff run and about 300 ft south of the extended runway centerline. Initial impact was in a gravel area between the main ramp and a helicopter ramp. The wreckage path headed 158° magnetic to the main wreckage, which stopped on a heading of 194°. The right engine nacelle struck the rear of a parked fuel truck. Postimpact fire consumed most of the fuselage and wings inboard of the nacelles. The outboard right wing had minimal damage; the left wing exhibited upward crushing from tip to nacelle. Both fuel tip tanks separated. The left propeller hub separated; all blades had chordwise scratches, gouging, and curling. The right propeller remained attached with similar blade damage. Flight control continuity was established except for a 1-ft section of unidentified cable embedded in molten metal. Flaps were retracted; landing gear was retracted. All engine controls were full forward and bent left. Fuel selectors were in the "main tank" position. Fuel was noted in auxiliary tanks. Elevator trim was 15° tab down; aileron trim 5° tab down; rudder trim streamlined.
Engine Examination
Both engines were shipped to Continental Motors for teardown. The left engine showed crankshaft and camshaft continuity; teardown revealed no preaccident anomalies. Fuel system components flow-tested without issues; magnetos produced sparks. The right engine had a fractured crankcase near the No. 5 main bearing, consistent with impact. No preaccident anomalies were found in its internal components, fuel system, or magnetos.
Medical Information
An autopsy determined the pilot's cause of death was asphyxia due to inhalation of smoke and fumes. Toxicology tests detected 34% carbon monoxide and 1.96 us/ml cyanide in blood, consistent with smoke inhalation. No ethanol or drugs were detected.
Engine Modification
An FAA airworthiness inspector noted that both O-470M engines had been modified by removing original Bendix pressure carburetors and installing TCM continuous flow fuel injection systems. The engine data plates were not re-marked as O-470M(CI) as required. The Cessna 310B type certificate does not include the O-470M(CI). The modification required a higher pressure engine-driven pump and airframe boost pumps, but no FAA Form 337 field approval for the conversion was found on file. Maintenance records were not located.