Incident Overview
A twin-engine airplane engaged in a local experimentation flight on behalf of the Federal Aviation Administration (FAA) experienced a hard landing at San Marcos Airport. During the final segment of the flight, as the aircraft leveled off, it struck the runway surface with excessive force. The impact caused the undercarriage to separate from the airframe, and the airplane subsequently came to rest on its belly.
Occupant Status and Aircraft Damage
All four occupants aboard the aircraft escaped the incident without injury. The airplane, however, sustained substantial structural damage and was declared beyond economical repair.
Official Findings
The probable cause of the accident was determined to be a hard landing resulting from improper operation of the powerplant and powerplant controls. Contributing factors identified in the official report include an improper level-off, overload failure, and the involvement of an FAA flight test pilot at the controls.