Pilots of the UPS Boeing 747-400 which crashed in Dubai earlier this month had been offered the chance to land at Doha after receiving a fire warning on the freighter.
The fire warning came about 28min after take-off from Dubai while the crew, bound for Cologne, were in contact with Bahrain air traffic control.
Investigators from the United Arab Emirates' General Civil Aviation Authority state that the crew was offered Doha, the capital of Qatar, as a diversion point.
But the pilots opted instead to return to Dubai. Initial analysis of the aircraft's flight recorders, says the GCAA, show that the situation deteriorated, with cockpit visibility becoming increasingly poor.
The crew declared a 'Mayday' but the inquiry has already determined that the 747 was too high as it attempted to land at Dubai, and overflew the airport before descending and crashing just west of the Dubai Silicon Oasis complex and north of the Minhad air base.
Neither of the crew members survived the 3 September accident. The GCAA says the cockpit-voice recorder and flight-data recorder were transported to the facilities of the US National Transportation Safety Board on 10 September, where their data was downloaded.