503
1955-FEB-13 · Monte Terminillo, Rieti, Italy

Sabena — Flight 503

Sabena Flight 503, a Douglas DC-6, crashed into the snow-covered slopes of Monte Terminillo during a severe winter storm, killing all 29 people on board. The aircraft was en route from Brussels to Rome when it drifted significantly off course due to strong crosswinds and navigational errors. The crew, believing they had passed the Viterbo NDB, began a descent in poor visibility and impacted the mountain at an altitude of approximately 1,700 metres. The wreckage was not located for eight days due to the remote terrain and extreme weather conditions.

Aircraft
Douglas DC-6B
Registration
OO-SDB
Phase
Cause
Souls on Board
29
Fatalities
29
Origin → Dest
Brussels-Melsbroek Airport, Belgium → Leopoldstad, Belgian Congo
Report

Investigation Summary

The flight was the first leg of a long-haul service to Leopoldstad, Congo. The aircraft involved (MSN 43063/60) was a Douglas DC-6 built in 1947. As the aircraft approached the Rome terminal area, it encountered a severe storm with heavy rain and snow. At 19:48 GMT, Ciampino controllers queried the crew about their position relative to the Viterbo NDB. The crew, seemingly uncertain, asked if the beacon was at full power. Despite receiving confirmation that the beacon was functional, the crew reported passing Viterbo at 19:50 GMT and requested descent to 5,500 feet. In reality, the aircraft had been pushed roughly 150 degrees off its intended course by unforecasted westerly winds. The descent was initiated directly into the Rieti mountain range. The impact occurred on the Costone dell'Acquasanta. Search efforts were severely hampered by the weather and the inaccessible nature of the site, which was located in a nature reserve. When rescuers finally reached the site on February 22, they found the forward fuselage shredded and the engines torn from the wings, with evidence that the landing gear had been extended just before impact.

Final Conclusions

The investigation concluded that the primary cause was the crew's failure to use all available radio aids to check and correct for wind drift. The crew held a false conviction that they were over the Viterbo beacon when they were actually miles off course. Contributing factors included crosswinds stronger than forecast and atmospheric conditions that severely degraded Medium Frequency (MF) radio reception, making navigation and communication difficult.

Video Analysis

No video analysis linked for this case file yet.

Systems & Failure Modes

i

Viterbo NDB

A Non-directional beacon used for navigation; the crew failed to accurately verify their passage over this point due to drift and poor reception.

i

Medium Frequency (MF) Radio

The primary band for navigation aids at the time, which the investigation noted was particularly susceptible to interference from the severe storm.

Interesting Facts

  • 01The aircraft was 150 degrees off course at the time of impact.
  • 02All 29 occupants died on impact, as confirmed by later autopsies.
  • 03The wreckage was found at an altitude of 1,700 metres (5,500 feet).
  • 04Among the victims was Marcella Mariani, an Italian actress and Miss Italia 1953.
  • 05The search and rescue operation involved calculating fuel exhaustion to narrow the search area to a 100km radius from Rome.

Location

Monte Terminillo, Rieti, Italy · 42.4667, 12.9833

Case File History

  1. CorrectionUpdated event timeline.
  2. CorrectionUpdated investigation summary.

Related Cases

Case ID · sabena-503-1955Last updated · Filed

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