NTSB Factual Report

On May 29, 2005, approximately 1215 central daylight time, a single-engine Debus/Mountain/Bowes Debus-Casst-Snoshoo experimental airplane, N102MB, was substantially damaged during a forced landing following a total loss of engine power while maneuvering at the Clarence E. Page Municipal Airport (F29), near Oklahoma City, Oklahoma. The private pilot, sole occupant of the airplane, sustained serious injuries. The airplane was registered to and operated by three individuals, one of whom was the pilot. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 air race flight. The local flight originated from F29 approximately five minutes prior to the accident.

A witness, who was located about mid-field, reported the airplane completing its third lap of an International Formula One Air Race when it aborted the race and turned south toward the center of the airport. The airplane then turned north and began a gliding descent for an approach to runway 35L (a 6,013-foot long and 100-foot wide concrete runway). At an altitude of approximately 200 feet above ground level (agl), the airplane was observed turning to the east, side stepping to runway 35R (a 3,502-foot-long and 75-foot wide asphalt/concrete runway).

Approximately 50 feet agl, the nose of the airplane was observed to have pitched upward "slightly" and entered into a left spin. Subsequently, the airplane impacted the edge of runway 35R in a near vertical nose-down attitude.

A Federal Aviation Administration (FAA) inspector, who responded to the accident site, reported the airplane came to rest inverted, approximately 70 feet from the initial point of impact. The fuselage and empennage remained intact from the roll bar aft. The fuselage, forward from the pilot seat, was destroyed. Both wings were separated from the fuselage and fragmented. The engine was separated from its mounts and both composite propeller blades were destroyed.

One of the owners/builders examined the modified four-cylinder engine and reported that the loss of engine power was due to a fracture of the number two piston to crankshaft connecting rod.

The pilot held a FAA private pilot certificate with a rating for single-engine land airplane. At the time of his last second-class FAA medical certificate, issued on February 3, 2005, the pilot reported his total flight time as 702 hours, with 50 hours in the preceding six months. Due do the seriousness of the pilot's injuries; a completed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) was not obtained.

At 1153, the automated surface observation station at the Wiley Post Airport, near Oklahoma City, Oklahoma, located 9 miles east of the accident site reported wind from 110 degrees at 9 knots, visibility 10 statute miles, broken cloud layer at 2,200 feet, broken cloud layer at 3,200 feet, temperature 23 degrees Celsius, dew point 18 degrees Celsius, and an altimeter setting of 29.87 inches of Mercury.

NTSB Probable Cause

The pilot's failure to maintain airspeed which resulted in an inadvertent stall. A contributing factor was the loss of engine power as result of the fracture of the number two piston to crankshaft connecting rod.