Accident Overview
The airplane did not gain altitude after takeoff and collided with trees and terrain off the departure end of the runway. The pilot reported no mechanical problems with the airframe and engines.
Weather Conditions
Prior to takeoff, the pilot received a computerized weather briefing indicating generally good conditions. The tower controller cleared the pilot to taxi to runway 21 and issued winds of 300 degrees at 10 knots, a direct crosswind. The density altitude was calculated to be 9,481 feet.
Pilot Actions
During the initial climb after liftoff, the pilot observed that the airplane had stopped climbing and requested wind information again. With the airplane not climbing and heading directly toward trees, the pilot maneuvered toward a clearing, but the left wing struck a tree and the airplane descended into the ground.
Aircraft Performance
The aircraft's gross weight at takeoff was 6,000 pounds. Review of the Airplane Flight Manual climb performance charts for that weight at the pressure altitude and reported outside air temperature indicated that the airplane should have achieved a positive rate of climb of about 1,100 feet per minute.
Wind Data
The airport was equipped with a wind information recording system consisting of four sensors. Three sensors recorded wind information at ground level only, placed at the approach, middle, and departure ends of the runway, recording data every 10 seconds. The system does not have the capability to predict or warn of wind shear events. During the aircraft's departure, the approach-end sensor recorded winds at 068 degrees at 1 knot; the middle sensor at 293 degrees at 5 knots; and the departure-end sensor at 302 degrees at 2 knots. Ten seconds later, the departure-end sensor recorded a wind increase of 10 knots, and the approach-end sensor recorded a wind shift from headwind to tailwind at 10 knots. A full analysis of the weather conditions indicated that, due to developing convection over the runway, the airplane likely encountered a wind shear (increasing tailwind) event that seriously degraded the takeoff and climb performance.