What happened
During the takeoff phase, a twin-engine airplane departed the runway without significant incident, rotating at 95 knots. While the pilot had previously monitored the monochrome weather radar during taxiing, which indicated a weather cell approximately 15 miles from the airfield, the takeoff roll itself proceeded normally. As the aircraft climbed at 110 knots with engines, propellers, and manifold pressure all set to maximum power, the crew initiated a 10-degree turn toward the Cotulla VOR.
Upon reaching an altitude of 1,500 feet MSL, the aircraft encountered a sudden and sharp descent. The vertical speed indicator recorded a downward rate of 800 feet per minute. In an attempt to stabilize the aircraft, the pilot leveled the wings and reduced the airspeed to 85 knots. Although the rate of descent eventually decreased to between 300 and 400 feet per minute, the aircraft continued its descent until it struck trees and the ground. The impact resulted in the destruction of the aircraft following a post-crash fire.
Findings
Investigation of the flight path and local weather conditions revealed that the aircraft encountered a strong downdraft during the climb. Subsequent analysis of Doppler weather radar imagery confirmed the presence of thunderstorms in the immediate vicinity of the airport at the time of the accident.