Accident Sequence
The pilot extended left base at 3.5 miles and lowered the landing gear. He reported receiving a landing clearance from air traffic control. After checking the landing gear down indication lights, he noticed black smoke emanating from the dashboard. Looking down at the control pedestal, he observed smoke and fire; the black smoke immediately obscured outside visibility. The passenger reported seeing the runway through an open window. The pilot landed the airplane, which bounced. On the second touchdown, the front nose gear collapsed, and the airplane skidded to a stop. Both occupants exited the airplane, which was subsequently destroyed by the ensuing fire.
Maintenance History
According to the airplane's maintenance records, the following work had been performed since the beginning of 2005: on January 28, the engine was removed and a remanufactured engine installed; on March 18, an annual inspection was completed; on March 30, an inverter located up and behind the instrument panel was replaced; and on April 11, the altimeter was replaced with an overhauled unit.
Postaccident Investigation
Postaccident examination focused on the landing gear hydraulic pump, which was located up and behind the instrument panel, and its associated tubular plumbing. Several fractures and failures were found in the plumbing. A metallurgist from the National Transportation Safety Board (NTSB) examined the hydraulic lines and found no evidence of preexisting cracking or fractures. Using a scanning electron microscope, he identified typical intergranular features with rounded edges, indicative of high-temperature overstress failures. Additionally, an NTSB fire expert examined the main wire bundle from under the instrument panel but could not determine an ignition source for the fire due to the extent of fire damage.