Background
A cargo pilot reported for work at 0200 hours and flew a leg from Burbank, California to Phoenix, Arizona. After arriving, he went to a company apartment for crew rest, arriving at approximately 0600-0630 hours. The pilot slept for about 5 hours, waking at around 1200 hours.
Accident
The pilot flew the return leg of the operation, taking off at 2055 hours. At 2230 hours, while maintaining a constant airspeed, heading, and altitude, the aircraft collided with a mountain. The mountain was located about 10 nautical miles south of the pilot's usual course.
Investigation
Investigators examined the aircraft and all components, noting no deficiencies. No evidence was found to indicate that the pilot attempted to avoid colliding with the mountain. Another pilot staying at the same company apartment reported that a box of Dimetapp decongestant pills was present on the pilot's shaving kit and that two pills were missing.