Accident Sequence
Prior to departure, the pilot observed winds from the northwest at 10 knots and selected runway 33 for departure. He performed a density altitude calculation, which determined a value of 9,747 feet above mean sea level. The takeoff was normal, and the pilot climbed at 80 mph. During the initial climb, the airspeed dropped to 60 mph. The pilot lowered the nose to regain airspeed and flew the aircraft under a set of power lines. Shortly thereafter, the aircraft impacted slightly inclining terrain. The four occupants exited the aircraft, and the airplane was subsequently consumed by fire.
Weather Conditions
At 1154, the closest reporting weather facility, located 10.4 nautical miles to the southwest, reported winds from 110 degrees at 7 knots. At 1254, winds were variable at 4 knots. Several pilots in the area reported encountering sudden wind shift conditions near the time of the accident.
Weight and Performance Data
According to calculated weight and balance data, the aircraft was slightly under maximum gross weight and within center of gravity limits at takeoff. The Airplane Flight Manual contained no performance data for takeoffs above 7,000 feet density altitude; the accident departure occurred at a density altitude of 9,747 feet.