What happened
On May 23, 2008, at approximately 01:24 MDT, a Beechcraft 1900C, registration N195GA, impacted terrain roughly three miles northeast of Billings-Logan International Airport in Montana. The aircraft, operated by Alpine Air Express, was performing a 14 CFR Part 135 contract mail flight. The pilot, who was the sole occupant, was killed in the crash, and the aircraft was destroyed by the impact and a subsequent fire.
The flight departed Billings-Logan Airport on an Instrument Flight Rules (IFR) flight plan. Shortly after takeoff, the pilot engaged in a sequence of events involving the aircraft's transponder. After the tower controller noted the pilot was using a VFR code, the pilot corrected the setting by switching to the correct transponder. During this period of distraction, radar data showed the aircraft's course drifted 30 degrees to the right, though the pilot eventually returned to the assigned heading.
After contacting departure control and receiving instructions to turn left to a heading of 290 degrees, the aircraft did not follow the instruction. Instead, the airplane began turning right and entered a rapidly descending right turn. The aircraft ultimately struck the ground in a nearly wings-level, nose-down attitude of more than 45 degrees.
The investigation
The investigation examined the wreckage, which included a primary impact crater and debris spread along a path on a magnetic heading of 196 degrees. The aircraft's engines and propellers were heavily damaged by the impact. Investigators found that the left engine bleed valve had recently been replaced, and the aircraft's maintenance logs showed recent calibrations of the torque and ITT systems.
Analysis of the cockpit warning annunciator panel showed that only one bulb filament was stretched, which was noted to be an unassigned bulb used only for testing. Radar data confirmed the aircraft's descent, and audio analysis of the pilot's final transmission showed the transmission ended abruptly, which could indicate the pilot released the microphone or a system anomaly occurred.
No evidence of airframe, control system, or engine mechanical failure was found that would have prevented normal flight. Due to the high energy of the impact, an autopsy and toxicological examination of the pilot could not be performed.