NTSB Identification: LAX07FA258.
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Accident occurred Thursday, August 30, 2007 in Cameron Park, CA
Probable Cause Approval Date: 09/26/2008
Aircraft: Raytheon Aircraft Company A36, registration: N1098F
Injuries: 2 Fatal,2 Serious.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
A television news crew was filming general airplane operations at the airport and captured the accident on video. The video begins with the airplane on its takeoff roll, accelerating almost 2/3 down the runway before getting airborne. The windsock at the approach end of the runway appeared limp, indicating little to no wind. Once airborne the airplane climbed to approximately 40 feet, the wings began to wobble, and it settled back down to the ground into the rising terrain off the end of the runway, slid on the ground, and abruptly flipped over onto its back. Immediately after liftoff the plane is observed to crab to the left about 7 degrees while remaining over the runway centerline, indicating the airplane went from a calm wind condition to suddenly being affected by a left crosswind very early in the initial climb. A video study concluded that the airplane's ground speed was 80 plus or minus 4 knots as it crossed the end of the runway, speeds consistent with the POH recommended speed for the climb. The airplane was equipped with an engine turbonormalizing system which, according to the supplemental type certificate (STC), allowed for an increase in gross weight to 4,000 pounds when operated in the normal category. The outside air temperature was 96 degrees F and the field elevation is 1,286 feet msl, which resulted in a density altitude of 4,125 feet. The airplane's weight at the time of takeoff was 4,095 pounds. The airplane was also instrumented with a JPI EDM-800 Engine Analyzer. The data revealed consistent engine operation throughout the takeoff and climb at a power level between 91 and 94 percent. The highest terrain elevation directly ahead of the airplane was 1,350 feet msl, approximately 4,860 feet from the point the airplane started its takeoff roll. The elevation difference between the point the airplane left the runway and the elevated terrain directly ahead was 80 feet. Based on the STC documentation, the calculated takeoff distance to clear a 50-foot object was 4,030 feet. An independent computer model simulating the performance of the airplane at a weight of 4,100 pounds and 4,100 feet msl density altitude resulted in the airplane climbing at 911 feet per minute and clearing the terrain directly ahead of it by 148 feet. The pilot reported that shortly after takeoff he felt a gust of wind from the left. The video depicts no wind at the midfield windsock and a left crosswind at the departure end, with trees in the background waving in what appears to be a moderate breeze. No determination could be made regarding whether the crosswind that was encountered had a tailwind or headwind component. Based on all the evidence it is likely that the airplane encountered a sudden wind from the left in the takeoff initial climb that degraded the airplane's climb performance and led to a stall mush condition.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The airplane's sudden encounter with a wind shift during the initial takeoff climb that resulted in degraded climb performance and a stall mush condition. Contributing to the accident was the airplane's over gross weight condition, high density altitude, the pilot's inability to compensate for the sudden wind shift, and rising terrain in the departure path. Full narrative available
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