NTSB Factual Report

On October 16, 1993, at 1050 hours mountain standard time, a Taylorcraft BC12-D, N94981, crashed after takeoff from the Yuma International Airport, Yuma, Arizona. The airplane was being operated as a visual flight rules (VFR) cross country personal flight to Tucson, Arizona, when the accident occurred. The airplane, owned and operated by the pilot, was destroyed by impact. The certificated private pilot, the sole occupant, received fatal injuries. Visual meteorological conditions prevailed.

About 1045 hours, the pilot was cleared to taxi for takeoff by the Yuma Air Traffic Control Tower (ATCT) ground controller. At 1048:30 hours, the pilot was cleared for an intersection takeoff on runway 26 by the local controller. At 1049:57 hours, the pilot stated, "Niner eight one, I'm gonna have to return back for landing, I'm having RPM problems, I'm returning back." At 1050 hours, witnesses heard the engine sputtering and observed the airplane begin a left turn to return to the airport. During the maneuver, the airplane suddenly descended in a near vertical nose-down attitude from about 120 feet above ground level (agl). The airplane came to rest in a parking lot about 7/10 of a mile from the airport.

The pilot held a private pilot certificate with an airplane single engine land rating. The pilot also held a mechanic's certificate with airframe and powerplant ratings. The most recent third class medical certificate was issued to the pilot on June 23, 1993, and contained the limitation that the pilot must wear correcting lenses for near and distant vision.

According to the pilot's logbook, the last entry was on September 27, 1993. At that time, his total aeronautical experience consisted of 491.3 hours. In the preceding 90 and 30 days priorto the accident, the logbook listed a total of 50.2 and 31.0 hours respectively.

Examination of the maintenance logbooks revealed that the airplane's recording hour meter (contained in the engine tachometer gauge) was replaced on June 24, 1981. At the time of the accident, the hour meter indicated 365.04 hours. The aircraft logbook indicated that the airplane had accumulated a total time in service of 1,974.44 flight hours. The most recent annual inspection was accomplished on December 3, 1992, 197.46 flight hours before the accident.

The original engine logbook was lost and the total accrued engine time in service is unknown. The current engine logbook noted that the most recent major overhaul was accomplished on August 9, 1988, 212.74 hours of operation before the accident. An annual inspection was accomplished on the date specified above for the airframe.

The airplane's flight manual lists three propellers in the limitations section for use with a Continental C-85-12F engine. They include a fixed-pitch wood propeller, and two metal fixed- pitch propellers, a McCaully IA90, and a Sensenich M74CK-2-46.

Review of the air-ground radio communications tapes maintained by the Marine Corps Air Station, Yuma, Arizona, revealed that the pilot communicated with the positions of ground and local control. A transcript of the air-to-ground communications between the aircraft and local control appears as Item 9.0 of this report.

After recovery, the airplane was examined on October 25, 1993, by a Federal Aviation Administration (FAA) airworthiness inspector and a Teledyne Continental Motors investigator who reported that the engine exhibited aft crushing of the exhaust tubes. The engine was equipped with a McCaully 1A101/DCM6948 fixed-pitch metal propeller. One propeller blade appeared bent forward with leading-edge damage. The second blade exhibited torsional and aft bending.

Examination of the engine cylinders revealed that the cylinder bores were smooth and without scoring. Heavy combustion deposits were present in the combustion chambers. All valves, springs, rocker arms, and pushrods were intact. Lubrication was present throughout the engine.

The pistons displayed heavy combustion deposits on the piston domes. All piston rings were intact and free moving. The piston skirts were lightly scored.

The crankcase main bearings were intact and clamped in their respective bearing webs. Some foreign object material was embedded in the bearing surface.

The crankshaft was intact and the journals were smooth and without scoring. The crankshaft gear was intact.

The camshaft lobes were smooth and without scoring. The cam journals were lightly scored. The camshaft gear was intact. The cam followers were smooth and without scoring.

The oil pump gears were intact and oil was present in the pump. The pump cover plate and pump chamber did not exhibit any scoring.

The oil screen contained slivers of ferrous metal and lint. The screen was otherwise clear.

Both magnetos produced spark upon hand rotation. The impulse coupling on the right magneto operated intermittently. The spark plugs exhibited no unusual combustion signatures.

The carburetor was separated from the engine. The float pin, float, and mixture plate chamber were corroded. The float was slightly crushed. The interior of the float bowl was corroded and contained a powdery, brown, dirt-like material. The fuel inlet screen contained rust, however, was otherwise clear.

A postmortem examination of the pilot was conducted by the Yuma County Office of Medical Examiner, 2400 Avenue A, Yuma, Arizona, on October 19, 1993. According to the report, the cause of death was attributed to cardiorespiratory failure due to extensive bone and soft tissue trauma.

A toxicological examination was conducted by the FAA Civil Aeromedical Institute (CAMI) on April 13, 1994, and revealed that 3.400 (ug/ml, ug/g) of Lidocaine was detected in the blood. Also, 2.200 (ug/ml, ug/g) of Lidocaine was detected in liver fluid. The pilot had been receiving emergency medical care at a local area hospital following the accident.

NTSB Probable Cause

a failure of the pilot-in-command to maintain adequate airspeed and subsequent inadvertent stall while maneuvering the airplane. Contamination of the fuel in the carburetor that produced a partial power loss was a factor in the accident.