Flight and Accident
A four-engine aircraft departed Lajes Airport in the Azores Islands at 0836 local time for a maritime patrol flight. Approximately two hours later, the crew reported their position and indicated that everything was proceeding normally. This was the last radio transmission from the aircraft.
At 1120 local time, while cruising at an altitude of 2,300 feet in limited visibility due to foggy conditions, the aircraft struck the slope of a 5,200-foot-high mountain at a speed of 220 knots and crashed. The wreckage was found in a wooded area near la Frontera, in the center of the island. At the time of the accident, three engines were operating while engine number 1 was shut down for loiter.
Cause
The official investigation determined that the accident was the consequence of a controlled flight into terrain. The following contributing factors were reported:
- The crew consumed alcohol until 2 o'clock in the morning.
- The crew started the mission without sufficient rest time.
- Failure of the authority to implement an effective aircrew surveillance program.
- Crew complacency for not adhering to sound navigation procedures.
- The crew was not properly briefed prior to takeoff and was probably not aware of the presence of Hierro Island.
- Poor visibility due to foggy conditions and rain falls.