NTSB Identification: SEA05LA189.
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Accident occurred Thursday, September 01, 2005 in Kalispell, MT
Probable Cause Approval Date: 02/28/2006
Aircraft: Ballhagen/Shyrock Q-2, registration: N12QJ
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

Just prior to the flight, the pilot, who was five hours into a ten hour experimental aircraft flight test regimen, readjusted the valve lash in the Subaru engine that powered the subject aircraft. At the beginning of the flight, he took off and climbed to about 1,000 feet above ground level (agl). After he rolled out on downwind, his ground crew contacted him on the aircraft radio to advise him that the aircraft's engine appeared to have been missing and running rough during the takeoff and initial climbout. About the time that the pilot received the radio transmission, the aircraft's engine quit producing power, and he decided to continue on around the pattern in order to execute a forced landing on the runway from which he had departed. As he turned from base to final, the pilot realized that he might not be able to stretch the glide to the end of the runway, but he elected to attempt to do so. When the aircraft descended to about 25 feet agl, its airspeed slowed to the point where it stall/mushed into the terrain about one-quarter of a mile off the end of the runway. In a post accident inspection, it was determined that the valve clearance in the engine had been set with a gap so small that when the internal engine temperature began to increase the exhaust valves in each cylinder did not completely close. Without the closure of the valves, sufficient compression was not created in the cylinders, and the engine stopped producing power.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot/owner's improper setting of the engine's valve clearance, leading to the failure of the exhaust valves to fully close and a total loss of power while on a VFR downwind, and the pilot/owner's failure to maintain sufficient airspeed as he tried to extend his power-off glide to the approach end of the runway.

Full narrative available

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