Investigation Summary
Flight 511 was a multi-leg international service from Prague to Conakry. After an uneventful flight from Zurich, the crew contacted Rabat-Sale Tower at 01:00 UTC and were informed of extremely poor visibility (10 meters) and ground fog. The pilot elected to divert to Casablanca-Anfa as an alternate. Upon reaching the Casablanca area, the weather began to deteriorate there as well, with the ceiling dropping from 150 meters to 100 meters within minutes. While the tower was coordinating a further diversion to the American-operated Nouasseur Air Base, the aircraft crashed 13 km south-southwest of Anfa Airport. The investigation could not definitively prove a single cause but leaned toward a weather-related CFIT during a high-speed descent.
Final Conclusions
The investigating commission could not reach a definitive conclusion regarding the cause, ruling out material or electrical failure as unlikely. The most probable scenario identified was that the crew, aware of rapidly deteriorating weather at their alternate airport, attempted a 'fast let-down' to maintain visual contact with the ground between stratus layers, leading to an accidental collision with terrain in unfavorable conditions.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
Ivchenko AI-20
The four turboprop engines powering the Ilyushin Il-18V.
Interesting Facts
- 01The aircraft was nearly new, with only 268 total airframe hours at the time of the crash.
- 02The aircraft's Manufacturer Serial Number (MSN) was 181002904.
- 03This was the second fatal crash of a ČSA flight numbered 511 involving an Il-18 in 1961.
- 04The crash occurred in line with runway 03 at Casablanca-Anfa Airport.
- 05Weather conditions at the time of the crash included a ceiling of approximately 100 meters (330 feet).