United Arab Emirates investigators have confirmed that part of the airframe from the Azza Air Transport Boeing 707-330C which crashed at Sharjah last week fell from the jet during take-off.
The UAE's General Civil Aviation Authority says part of the aircraft's structure "located around the engine" separated from the 707 as it departed on 21 October.
It has temporarily banned Azza Air Transport from operating to the UAE until the inquiry is complete.
In a preliminary report into the accident the GCAA says the aircraft had been carrying air conditioning units, automotive parts, computers and tools, and was transporting a crew of six, none of whom survived.
The 707's departure to Khartoum, at 15:29, was captured on airport surveillance cameras and video footage had indicated a falling object as the aircraft climbed away.
The GCAA says the aircraft part - the identity of which has yet to be fully disclosed - separated from the 707 and dropped onto the runway.
Around 20 seconds into the flight, it adds, the aircraft was "found to be on a right turn" which continued until the aircraft struck the ground, some 1.2km from the approach end of Sharjah's runway 12.
The GCAA says the ban on Azza's operations is a "preventive measure".
It has drawn together an investigation team, headed by five GCAA members. While the inquiry is at an early stage, it says there is no indication that Sharjah Airport operations or infrastructure contributed to the crash.