N1997D

HISTORY OF FLIGHT

On July 15, 1995, at 1343 central daylight time, a Beech C35, N1997D, was substantially damaged during a forced landing in Plano, Texas. The commercial pilot/owner received minor injuries and the passenger was seriously injured. The personal flight was conducted under Title 14 CFR Part 91. Visual meteorological conditions prevailed and a flight plan was not filed.

The pilot reported the following information during a personal interview conducted by the investigator-in-charge. One week prior to the accident, after topping off the main tanks, he had been unable to start the airplane. He found water in the airplane's fuel system and drained approximately 1 pint of water from the fuselage auxiliary fuel tank. The pilot then flew the airplane on a 118 nautical mile cross country flight.

The airplane was not flown again until the morning of July 15, 1995. Prior to flight, the pilot drained the fuel sumps and found no water. He flew from his residence at Airpark-Dallas in Plano, Texas, to Lancaster, Texas, a distance of 27 nautical miles. At Lancaster, after experiencing difficulty in starting the airplane, the pilot drained fuel from the main sump and the left tank and found no water. During the return trip to Plano, he switched from the left main fuel tank to the fuselage auxiliary tank and the engine lost power. After the pilot added full throttle, switched back to the left tank, and turned on the electric fuel boost pump, the engine regained power.

The airplane was on final approach to land on runway 16 at Airpark-Dallas when the engine lost power for the second time. The pilot turned on the boost pump, added full throttle, but did not change fuel tanks. He attempted to land in a field; however, prior to touchdown, the airplane struck a tree and then impacted the ground. The pilot stated "he believed both engine failures were caused by water contamination in the fuel system."

Examination of the airplane by a Federal Aviation Administration inspector took place approximately one hour after the accident. The inspector reported that the fuel selector was in the "left fuel tank position" and the left main fuel tank was "dry." He further reported that fuel was leaking from a ruptured right fuel tank and the fuselage auxiliary tank was "dry." Local authorities drained "approximately 10 gallons of fuel" from the right main fuel tank.

AIRCRAFT INFORMATION

The Beech C35 Pilot's Operating Handbook contains an "Engine Malfunction in Flight" checklist (copy attached) which calls for the pilot to change fuel tanks following a loss of power.

WRECKAGE AND IMPACT INFORMATION

The airplane came to rest in an open field approximately 0.5 statute miles north of Airpark-Dallas. Branches were broken from the top of a 30 to 35 foot tall tree located 135 feet from the airplane. The measured magnetic heading from the tree to the airplane was 170 degrees. A ground scar measuring 12.5 feet by 2.5 feet was located between the tree and the airplane. The nose landing gear was collapsed and the airplane was resting on the left and right main landing gear and the lower cowling. The right wing and fuselage sustained structural damage. Following the on-site investigation, the airplane was moved to the owner's hangar for further examination.

Visual examination and draining of the left main tank revealed 2 to 3 ounces of fuel and approximately 0.5 ounces of water trapped below the level of the fuel outlet from the tank. Draining the main fuel sump, yielded 2 to 3 ounces of fuel and less than 0.5 ounces of water. The water level in the sump was below the level of the fuel outlet to the engine. No measurable quantity of fuel could be drained from the fuselage auxiliary fuel tank. The fuel boost pump switch was in the "ON" position. A single fuel quantity gage was installed in the instrument panel. The left/right selector switch for the fuel quantity gage was in the up (right tank) position. Disassembly of the fuel selector valve confirmed that the left main tank was selected.

Engine continuity was confirmed to all of the cylinders and to the accessory section. Both magnetos sparked at all terminals when the crankshaft was rotated by hand. The carburetor was separated at the throat and rotated rearward 90 degrees. No fuel was found in the carburetor and the carburetor fuel screen was unobstructed. Continuity was established for the throttle, mixture, and carburetor heat controls.

ADDITIONAL INFORMATION

The airplane was released to the owner on July 16, 1995, and all of the retained aircraft records were returned to the owner on July 18, 1995.