Dubai: The UAE's General Civil Aviation Authority (GCAA) has released the updated Air Accident Preliminary Report of a Boeing 747 freighter which crashed around 10 kilometres south of Dubai International Airport in September last year.

The American cargo plane, belonging to United Parcel Service (UPS), one of the world's biggest courier services, had crashed near the Emirates Road and Al Ain highway, killing two crew members.

The Air Accident Investigation department of the GCAA reported several key findings after an analysis of the crash, which are included in the Air Accident Preliminary Report.

"The key findings are summarised in several points. First, a fire started on-board the aircraft's main cargo deck after departure from Dubai. Then smoke and fumes in the flight deck hindered the crew from managing the aircraft and the emergency.

"There were failures of the aircraft's air conditioning, oxygen and flight control systems, The inability to view the flight instruments prevented the crew from operating the aircraft normally for the descent and return to Dubai and from changing radio frequencies from Bahrain ATC to Dubai ATC. Then the Captain experienced problems with the supply of oxygen to his oxygen mask, which required him to leave his position on the flight deck," the report said.

In complex air accident investigations, there are multiple lines of enquiry and analysis.

To date the investigation has identified several areas to pursue in relation to identifying the root cause, the associated causal factors and the probable causes of this accident, it added.