Accident Overview
The accident occurred when an airplane collided with mountainous terrain approximately five miles from the departure airport during a dark night takeoff. The aircraft had departed and was climbing when it struck the mountain.
Radar Data
Review of recorded radar data showed that the airplane initially transmitted a secondary beacon code 7267, which was the code assigned for its earlier inbound arrival. At 2021:08, the code appeared on the runway with a mode C report consistent with airport elevation. Subsequent returns at 2021:12 and 2021:19 showed altitudes of 1,600 and 1,700 feet, respectively. Between 2021:08 and 2021:38, the target proceeded on a northeasterly heading of 035 degrees (runway heading), climbing to 2,000 feet and accelerating to 120 knots ground speed. Between 2021:38 and 2021:52, the heading shifted to an average of 055 degrees, with a calculated climb rate of 1,300 feet per minute and ground speed increasing to 170 knots. At 2022:23, the transponder code changed from 7267 to the VFR code 1200. The target continued climbing at 1,200 feet per minute, ground speed averaged 180 knots, and heading remained at 055 degrees. The last radar return at 2022:53 showed an altitude of 3,500 feet. The accident site elevation was 3,710 feet, located 0.1 miles from the last target.
Witness Observations
Several ground witnesses living at the base of the mountain where the accident occurred reported hearing the airplane and observing its lights. They described seeing the aircraft begin a right turn when a large fireball appeared coincident with the collision with the mountain.
Examination
No preimpact mechanical malfunctions or failures were identified during an examination of the wreckage. The radar data revealed that the pilot changed the transponder code from the arrival IFR assignment to the VFR code approximately 30 seconds before the impact, and this may have been a distraction.
Probable Cause
The official finding states the probable cause was the pilot's failure to maintain an adequate altitude clearance from mountainous terrain. Contributing factors were dark night conditions, mountainous terrain, and the pilot's diverted attention.