Accident Details
The pilot initiated a downwind takeoff on runway 18 with two passengers aboard. According to the pilot, after a ground run of 600 feet, he rotated the airplane for takeoff. The airplane climbed to about 40 feet above the runway, then stopped climbing and stopped accelerating.
Witnesses reported that the airplane entered a steep nose-high attitude during takeoff. After climbing briefly, the wings rocked (or wobbled) to the left and right. The pilot then lowered the nose briefly and stated that he increased engine power '2 ticks into the yellow (arc).' He aborted the climb and attempted to land.
After ground contact, the airplane veered off the runway. After stopping, a fire erupted, which resulted in further damage.
Aircraft Modifications and Weight/CG
The airplane's reciprocating engine had been replaced with an Allison 250-B17C turbine engine per Supplemental Type Certificate (STC) SA3523NM, by Tradewind Turbines, Amarillo, TX.
The Pilot's Operating Handbook indicated that a ground roll of 1,800 feet would have been required for the takeoff conditions. The airplane was estimated to be 76 pounds over its maximum takeoff weight and about 2 inches beyond the forward center of gravity (CG) limit (as listed in the STC). Additionally, the pilot did not use maximum power for takeoff as described in the STC.
Environmental Conditions
The wind was estimated to be from 350 degrees at 15 knots.