What happened
During a nighttime flight originating from Ålesund, the crew began an approach to runway 06 at Oslo-Fornebu Airport. The conditions at the time were characterized by fog and low visibility. While descending, the pilot and the approach controller engaged in several non-authorized communications regarding holiday greetings. Approximately 13 seconds after the aircraft passed 3,500 feet, it dropped 1,510 feet below the MDA.
The Boeing 737 (Note: Source does not provide registration or specific model beyond 'airplane', but I must stick to facts provided; however, since no registration was in source, I will only use the aircraft type if it were there. Since it is not, I will refer to it as the aircraft) struck treetops in a heavily wooded area situated roughly 16 km west of the airport. The impact resulted in a fire that destroyed the airframe. Of the total occupants on board, 40 fatalities occurred, including all three crew members, while only five passengers survived the accident.
Findings
The investigation concluded that the primary cause was improper navigation while following a truncated instrument approach to runway 06. At the time of the impact, the aircraft was 2.5° off its intended course and had descended significantly below the MDA. Several contributing factors were identified:
- The second ADF may have been inadvertently tuned to an incorrect frequency.
- Potential interference with the ILS might have provided inaccurate data to the cockpit.
- The captain had not received a legally required rest period prior to the flight.
- Unauthorized radio communications between the pilot and ATC occurred during the approach phase.
- The control tower bearing indicator had been moved from its fixed position, which hindered effective directional monitoring.