Avro 748

The aircraft was landed at a point from which it could not be stopped under the prevailing conditions. Contributing to the occurrence were the lack of immediate propeller ground fine pitch and the choice of runway 03 as the landing runway. A possible contributing factor was the inappropriate information in the then-current runway analysis manual.

The engine failure was caused by high-cycle fatigue cracking of the High Pressure (HP) turbine disc. Four similar Dart turbine failures had occurred over the previous 26 year period. These had been attributed to a combination of turbine entry flow distortion and turbine blade wear. The following causal factors were identified:
- Significant reduction in the fatigue strength f the HP turbine disc due to surface corrosion,
- Inadequate control of the fit between engine turbine assembly seal members, possibly influenced by inadequate turbine clamping blot fit, causing sufficient reduction in the natural frequency of an HP turbine disc vibratory mode to allow its excitation within the normal operating speed range and consequent excessive stressing of the disc,
- Fuel leakage from the engine bay fuel system, resulting in a major nacelle fire,
- Failure to identify the turbine assembly seal member fit and HP turbine disc corrosion as possible contributors to disc fatigue damage after previous similar failures.

The exact cause of the accident could not be determined and the official accident report was not published by the Senegal Government. Nevertheless, The determination of the causes of the accident is therefore based on the expert reports ordered by the French investigating magistrate and the position of the locking pin of the left supply valve observed after the accident. Experts conclude that the left engine has stopped due to the closing of the fuel supply valve. The poor quality of the fuel was also blamed, which, before the accident, led Air Senegal to ask a chemical engineer from Shell-Senegal to test the fuel and the refueling operations. The engineer, while noting the poor quality of the fuel, came to the same conclusions as the experts. In France, operational tests were carried out on a similar aircraft and, moreover, fuel analyzes were carried out by the Accident Investigation Bureau. To these different expertises were added those of the government of the United Kingdom, the country of the manufacturer of the aircraft, and the results of a test carried out by British Aerospace with the same aircraft. The various analyzes carried out on the drums used for refueling showed that water was not present in the drums but in the pump used for refueling. It appears that the pump had been disassembled and the filters removed before filling the aircraft's tanks. As a result, the tiny amount of water that could have been found in the tanks would not have allowed the fuel to be considered contaminated and therefore unfit for consumption. The court, considering itself sufficiently informed by all these expertises, refused to grant the civil parties a further investigation 12 years after the facts. For the magistrates, there is no doubt that the determining cause of the accident was the closure of the left fuel isolation valve. The various investigations finally made it possible to determine that a ground mechanic had carried out a technical intervention under the left wing before the departure, at the level of the engine, but the exact nature of this intervention could not be established with precision. In its judgment, the court recognized that various indirect causes may have played a role in the occurrence of this air disaster: anomalies in the storage and distribution of fuel, nervousness and intense stress generated around the aircraft due to overbooking, irritability of the captain who, impatient to take off, did not consider certain checks useful. However, the magistrates have ruled, the determining cause perfectly defined by the various experts is the closing of the isolation valve of the left engine of the aircraft. On May 14, 2009, more than 12 years after the incident, Senegalese mechanic Moustapha Diagne was sentenced to 30 months' imprisonment with a 15-month suspended sentence. The length of the firm prison sentence is the length of the pre-trial detention that the defendant, after being extradited, had already served.

Wrong approach configuration on part of the crew who landed the aircraft too far down the runway, reducing the landing distance available. Also, it was reported that the braking action was poor as the grassy runway was wet.

Controlled flight into terrain.

Shot down by a surface-to-air missile fired by Tamil separatists.