En route, the aircraft encountered bad weather, and conditions were poor in Cairo due to the presence of sandstorms.

The crew of Flight 749 contacted Mirsair's Operations about diversion options.

The flight crew also reported they were flying through thunderstorms with icing conditions, that two of the aircraft's altimeters were giving different readings, the magnetic compass being unserviceable, and that there was a crack in a cockpit window panel due to the thunderstorms.

[1][2] Accident investigators determined that "the accident arose from the descent of the aircraft below the safe flight altitude in the final approach and the impact of the port wing against the sand dunes lying to the northeast of the aerodrome.

It is probable that the cause of descent of the aircraft below the safe level was due to the change from IFR to VFR, taking into consideration that considerable time would have been needed for the pilot to have adapted to this change in the prevailing weather conditions.