GOODYEAR, AZ, USA
N94BV
BULSKY SKYBOLT
DURING THE LOCAL AREA FLIGHT, THE ENGINE CRANKSHAFT IDLER GEAR LOCKPLATE BROKE WHICH ALLOWED THE ATTACH SCREWS TO BACK OUT. THE IDLER GEAR BECAME LOOSE AND ITS GEAR TEETH WERE DAMAGED. A PARTIAL FAILURE OF THE ENGINE-DRIVEN FUEL PUMP, WHICH IS OPERATED BY THE IDLER GEAR, CAN ALLOW THE ENGINE POWER TO SUDDENLY REDUCE TO IDLE. DURING THE SUBSEQUENT EMERGENCY LANDING, THE AIRPLANE COLLIDED WITH SOME TREES AND BUSHES.
On March 30, 1995, at 1805 hours mountain standard time, a Bulsky Skybolt experimental airplane, N94BV, collided with some trees and bushes during an emergency landing about 8 miles southwest of Phoenix Goodyear Municipal Airport, Goodyear, Arizona. The emergency landing resulted from a sudden loss of engine power. The pilot was conducting a local visual flight rules personal flight. The airplane, registered to and operated by the pilot, was destroyed. Neither the certificated commercial pilot nor his passenger was injured. Visual meteorological conditions prevailed. The flight originated at the Phoenix Goodyear Municipal Airport about 1715 hours. The pilot told National Transportation Safety Board investigators in a telephone interview conducted on March 31, 1995, that he was returning to the departure airport when the engine power reduced to idle. The pilot immediately executed an emergency landing to a dirt road. During the landing rollout, the airplane wing struck a cactus bush and nosed over. The pilot also said the airplane had " . . . a lot of fuel . . . ." The pilot repeated his telephone statement in the accident report. He added, however, that the terrain was covered with rocks, trees, bushes, and "big cactus." During the emergency landing, he intentionally struck the trees to absorb the initial impact energy. On April 20, 1995, maintenance personnel disassembled the engine, a Lycoming IO-540-T4A5, for examination at Air Transport, Phoenix, Arizona. A Federal Aviation Administration (FAA) airworthiness inspector from Scottsdale (Arizona) Flight Standards District Office supervised the examination. The inspector reported that the oil screen contained ferrous and nonferrous metal. The crankshaft idler gear, part No. LW-10290, was found loose and damaged. The inspector said that two screws, part No. STD-1838, that attach the crankshaft idler gear shaft to the engine case, were "backed-out". The lockplate, used to safety the attachment screws, was broken into several pieces. The pieces were found in the oil pan. The inspector reported that the fuel pump is operated by the crankshaft idler gear.
fuel starvation due to the partial failure of the fuel pump caused by the broken crankshaft idler gear attachment screw lockplate. The unsuitable terrain and trees were factors in this accident.
Source: NTSB Aviation Accident Database
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