Investigation Summary
The flight from Paris was uneventful until the approach to Rabat, where weather conditions were rapidly deteriorating due to low fog. The captain initially considered diverting to Casablanca but decided to attempt a landing at Rabat using the KJ non-directional beacon (NDB) and the runway 04 localizer. During the final stages of the flight, the control tower attempted to warn the crew twice: first, that the NDB was not aligned with the runway centerline, and second, that visibility had plummeted to less than 100 meters. The crew did not acknowledge either transmission. The aircraft struck the ground with its nose gear first, followed by the main gear, before hitting a rock and a hill, which caused it to burst into flames. The investigation focused heavily on the Kollsman window altimeter, a three-pointer instrument known to be difficult to read. Tests conducted by various European airlines confirmed that even highly trained crews could easily make a 1,000-foot reading error, particularly during high-workload phases of flight.
Final Conclusions
The Board of Inquiry concluded that the probable cause was an error in instrument reading. Specifically, the pilot likely made a 1,000-foot error at the start of the descent and maintained this misconception while focusing on the secondary pointer to reach what he believed was the minimum authorized altitude. The board noted that the Kollsman window altimeter design was delicate to interpret. Contributing factors included the unfavorable and rapidly changing weather conditions and the crew's failure to respond to critical warnings from air traffic control regarding NDB alignment and visibility.
Photographic Evidence (1)
Video Analysis
How A Small Mistake Cost 77 Lives | The Crash Of Air France Flight 2005 — A detailed look at the 1961 crash of an Air France Sud Caravelle in Morocco, focusing on the altimeter reading error that led to the disaster.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Systems & Failure Modes
Kollsman Window Altimeter
A three-pointer altimeter where the crew must synthesize readings from multiple hands; the investigation found it prone to 1,000-foot reading errors.
KJ Non-Directional Beacon (NDB)
A radio transmitter used for navigation; in this case, it was not aligned with the runway, a fact the tower communicated but the crew did not acknowledge.
Interesting Facts
- 01The aircraft was a Sud Aviation SE-210 Caravelle III, Manufacturer Serial Number (MSN) 68, which was less than a year old at the time of the accident.
- 02All 77 occupants, including 6 crew members and 71 passengers, were killed in the crash.
- 03The investigation found no evidence of technical failure in the aircraft or air traffic control equipment.
- 04The KJ NDB used for the approach was located 800 meters west of the airport and was not aligned with the runway.
Safety Actions & Advisories
Altimeter Design Review
The investigation highlighted the dangers of the three-pointer altimeter design, contributing to industry-wide shifts toward drum-pointer altimeters to reduce 1,000-foot misreadings.