Accident Overview
A sales demonstration flight ended when the aircraft collided with the upsloping face of mountainous terrain approximately 17 nautical miles north of the destination airport. The accident occurred under dark, nighttime visual meteorological conditions after about 22 minutes of flight. The moon's visible disk illumination was 19 percent. No roads or ground structures were present in the vicinity to provide ground reference or illuminate the accident area terrain.
Flight Path Details
The direct course between the departure and destination airports (71 nautical miles apart) was 180 degrees magnetic. Recorded radar data indicated that during the last 3 minutes of flight, the airplane's average ground track was 176 degrees, and its average ground speed was 168 knots. The radar ground track ended near the centerline of the direct course and about one-quarter mile north of the initial point of impact (IPI). The wreckage distribution path was 640 feet long on a magnetic bearing of 177 degrees.
Impact and Aircraft Condition
An examination of the impact ground scars disclosed that the airplane was in controlled flight in a shallow descent when it collided with the terrain. No evidence of any preimpact failures or malfunctions was found during the wreckage examination of the airframe structure and the engine. The avionics components were too impact-damaged to provide data.
Visibility and Lighting Conditions
Review of the radar-derived flight track in conjunction with the associated underlying terrain and ambient lighting conditions revealed that the terrain would have been, at best, marginally visible to the pilot. Initially during descent, the lights of the greater Phoenix area would have been visible in the distance, but they disappeared from the pilot's view seconds before impact.
Equipment and Operational Context
The airplane was equipped with an autopilot, a KLN 94 global positioning satellite receiver, and a KMD 550 multifunction color display. The KMD 550, if operated in topographic mode, had the capability to display terrain elevation information. However, the investigation was unable to ascertain if the pilot was using the multifunction display to receive topographic data while descending toward the destination airport. The KLN 94 and KMD 550 Pilot's Guides contain a caution: "NEVER USE THE TOPOGRAPHIC ELEVATION DISPLAYED ON THIS EQUIPMENT AS YOUR SOLE REFERENCE FOR TERRAIN AVOIDANCE."