CHI97LA052

During cruise flight on a bright night the pilot said the airplane '...experienced a noticeable drop in manifold pressure... the engine lost power and began to backfire... different power settings didn't help.' The pilot said the inside of the airplane's windshield frosted up after the engine lost power. He said he used the side window and landing lights as an aid for landing. According to the pilot he decided to land in a field next to the road on which he was going to land because of powerlines. The on-scene investigation revealed no fuel in the fuel tanks or electric fuel pump. The engine was test run to the manufacturer's specifications once fuel was added to the airplane.

On January 12, 1997, at 2015 central standard time (cst), a Piper PA-24-250, N6495P, piloted by a private pilot, was substantially damaged during an off airport hard landing following a total loss of power while in cruise flight. The personal 14 CFR Part 91 flight was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot and two passengers reported no injuries. The flight departed Sheridan, Wyoming, at 1600 cst.

During an interview with the pilot, he said the flight was operating in bright night co ditions. According to the pilot's written statement, "... I experienced a noticeable drop in manifold pressure and within moments the engine began to run rough, I applied carb heat at the first sign of power loss... I elected to climb in order to get as much altitude as possible. The engine lost power and began to backfire. I tried different power settings but it didn't help. We continued to have backfiring and engine surging, and the power became too low to maintain level flight."

The pilot said the total loss of power resulted in having the inside of the windshield frost up. He said, "...our forward visibility was eliminated." The pilot said he used the side window and landing lights as aids for landing. He said the road he had chosen for the landing had powerlines along it. "I elected to put us down in the field next to the road."

The on-scene investigation revealed wrinkled fuselage bulkheads from the firewall to the wing's trailing edge. The forward fuselage was buckled downward at the bottom of the windshield, and behind the cockpit entrance door. Multiple wrinkles were observed on the top of the wing. The main landing gear had sheared off at their mounts. The fuel tanks were empty. The fuel system was not damaged. The electric fuel pump chamber did not have any fuel in it.

A Federal Aviation Principal Maintenance Inspector (PMI) conducted the on-scene investigation for the NTSB. According to the PMI, 5 gallons of fuel were added to N6495P's wing fuel tanks. The PMI said the engine was test run on the airframe. The PMI said the engine ran to the manufacturer's performance specifications. He said the fuel selector worked at all positions during the engine test run.