Accident Details
A Cessna 441 twin-engine turboprop, operated by the US Customs Services, was involved in a collision with terrain during an authorized night tactical flight. The flight departed during daylight hours and continued into astronomical twilight. The pilots did not undergo dark adaptation prior to entering night conditions. Dark adaptation was further impeded by flight through varying light conditions created by terrain and ambient light levels. With night vision impaired, the pilot in command could not distinguish the relief of the terrain. The aircraft struck a small ridge that rose abruptly by 300 feet. Both occupants were killed.
Pilot Qualifications and Crew Performance
The copilot did not meet the currency standards required by the US Customs Services and was not qualified to fly the Cessna 441. The copilot also lacked recent instrument time and had not received adequate transition or upgrade training. The pilot in command experienced excessive workload and demonstrated inadequate crew coordination. In-flight planning and decision-making by the pilot in command were inadequate. Visual lookout was inadequate for both the pilot and copilot, and both had inadequate visual and aural detection.
Official Findings and Probable Cause
The official investigation listed the occurrence as an in-flight collision with terrain during the maneuvering phase. Findings included uphill terrain, misjudged altitude by the pilot in command, excessive workload, night light conditions, failure to maintain proper altitude, inadequate visual lookout by both pilots, lack of recent instrument time and inadequate training for the copilot, and inadequate flight planning and crew coordination by the pilot in command. The probable cause is the in-flight collision with terrain due to these factors.