Incident Overview
A witness saw the airplane taxi from the pilot's hangar to the runway without performing an engine run-up. Shortly after takeoff, the engine lost power. Witnesses reported that the airplane cleared utility lines and then pitched nose down, impacting the terrain in a nose-low attitude.
Witness Accounts
The passenger stated that she did not think the private pilot performed an engine run-up prior to takeoff. She added that after the engine lost power, the pilot reached down to the lower section of the center column area and turned something. Another witness, an acquaintance of the pilot, reported that the pilot was in the habit of turning the fuel selector to the off position when hangaring the aircraft due to past fuel leaks. This witness also noted that the pilot had previously experienced a loss of engine power while taxiing because the fuel selector was in the off position.
Investigation Findings
The fuel selector valve is located on the bottom of the center control column and is operated by manually rotating the selector valve handle to one of four positions: OFF, LEFT, BOTH, and RIGHT. The fuel selector valve was found in the left fuel tank position. Fuel was present in the fuel line immediately upstream of the boost pump, but no fuel was found between the gascolator and the boost pump. The airplane had been modified by a Supplemental Type Certificate (STC) for a Continental IO-550 engine; part of the installation involved adding a 1-quart capacity header tank between the selector and the fuel control unit. The engine was operated on a test stand and no anomalies were noted that would have prevented its operation.
Checklists and Pilot Practices
The Preflight Inspection, Before Starting Engine, and Before Takeoff checklists instruct the pilot to place the fuel selector valve in the on or both position. The pilot's habit of turning the fuel selector to off when hangaring the aircraft was cited as a potential issue.
Toxicological Tests
Toxicological tests on the pilot were positive for paroxetine, a prescription antidepressant drug, and verapamil, a prescription medication for high blood pressure. Paroxetine is not approved by the FAA for use during flight, although current medical literature indicates the drug does not appear to have adverse performance effects when taken in therapeutic dosages. The subtle effects of higher than normal doses have not been systematically investigated, though symptoms of overdosages have been reported to include sedation and dizziness. The pilot did not report the use of these medications on his last application for an airman medical certificate.