Accident Description
A pilot and a passenger were returning home from an elk hunting trip in the Idaho backcountry. The airplane was loaded with four elk quarters and personal gear. A witness heard the airplane taking off and noted that it "didn't sound right." Looking toward the 2,000-foot-long grass airstrip, the witness saw the airplane "barely off the ground" heading south. The airplane was "wallowing back and forth, trying to stall out." The witness further stated that the "motor sounded like a boat cavitating" and "the nose of the airplane was pointed up." The witness watched the airplane veer left and impact the ground tail first. The nose then "slammed into the ground," and the airplane nosed over, coming to rest inverted. A fire erupted, destroying the fuselage and inboard sections of the wings.
The accident site was about 1/4 mile from the end of the runway, offset to the left of the runway centerline, at approximately the same elevation as the runway, on level grass-covered terrain.
Aircraft and Pilot Information
Examination of the airframe and engine revealed no evidence of any abnormalities that would have prevented normal operation. The pilot began flying this airplane—which had been modified by replacing its original reciprocating engine with a gas turbine engine—about 4 months before the accident. According to his logbook, he had accumulated about 22 hours flight time in it. He had about 1,167 hours in other non-modified airplanes of the same make and model.
Weight and Balance
An estimated weight and balance placed the airplane's takeoff weight at 3,729.4 pounds, which was below the maximum gross weight of 4,000 pounds. The estimated center of gravity was 48.57 inches, which was within, but near, the aft limit of 49 inches. A short field landing performance chart indicated that for the approximate accident conditions, the takeoff ground roll would be 1,581 feet and the total distance to clear a 50-foot obstacle would be 2,461 feet.
A pilot who had experience flying the accident airplane stated the following with respect to its performance: "Weight and balance is very, very critical. With weight aft, you really need to hold the nose down and gain airspeed on takeoff."