Flight Details
The flight was en route from Campo Grande to Vilhena. While at cruising altitude, the crew received the last weather bulletin for Vilhena, which indicated conditions below minimums. The copilot, who was under a line check on this flight, suggested diverting to the alternate airport. The captain/instructor, however, preferred to attempt an approach via Echo 1 and the NDB for runway 03. The plan was to divert to the alternate airport if visual contact was not established at decision height.
Decision Height Error
The copilot set the decision height at 2,500 feet, which was incorrect; the correct decision height was 2,560 feet. Neither the copilot nor the captain realized this mistake before beginning the descent to Vilhena Airport.
Approach and Blackout
During the approach, the captain instructed the copilot to monitor the horizon. The copilot focused on the horizon and failed to monitor the altimeter. Meanwhile, the captain attempted to establish visual contact with the ground and runway lights. It was later confirmed that the city of Vilhena had experienced a general blackout, resulting in a lack of visibility.
Accident and Evacuation
On final approach, the aircraft descended below the Minimum Descent Altitude (MDA), struck trees, and crashed less than one kilometer from the runway threshold. The aircraft burst into flames. All 16 occupants evacuated safely, but the aircraft was destroyed by fire.
Probable Cause
The official findings identified the following: poor crew coordination, wrong approach configuration, the crew's attention was focused on their respective tasks without monitoring the approach configuration (causing the aircraft to descend below the glide), the captain/instructor failed to supervise properly the copilot's maneuvers, no approach briefing, and lack of visibility due to a general blackout.