Accident Overview
The aircraft departed during low ceiling, low visibility, and night conditions. Shortly after takeoff, the aircraft impacted a reservoir. Analysis of radar data indicated the aircraft was in a 45° descending turn. Examination of the aircraft trim system showed that the aircraft was trimmed for level flight. No voice or flight data recorder was on board.
Crew and Communications
A review of ATC communications indicated that the captain was communicating with ATC, allowing the first officer to accomplish the flying duties. Witnesses stated that before the flight, the captain had complained of illness but decided to report for duty. Company records showed instances of substandard performance by the first officer.
Aircraft and Systems
Examination of the wreckage revealed no indications of powerplant or system failures. However, there was evidence that the SAS warning light was illuminated, the SAS switch was in the off position, and no SAS system malfunction could be found.
Investigation Findings
The investigation found company oversight of training, operations, and inadequate FAA supervision. All 12 occupants were killed.
Probable Cause
According to the National Transportation Safety Board, the probable cause of this accident was a failure of the flight crew to maintain a proper flightpath. Contributing to the accident were the ineffective management and supervision of flight crew training and flight operations, and ineffective FAA surveillance of AVAir.