Namibian investigators have found no indication of mechanical malfunction on the LAM Mozambique Embraer 190 which crashed while en route from Maputo to Luanda.
The Namibian transport ministry states that the cockpit-voice and flight-data recorders “withstood the tremendous impact” of the crash on 29 November.
But initial examination of the wreckage as well as preliminary data from the recorders shows “no evidence” of mechanical failure, it adds.
It stresses that the inquiry is not complete but making “good progress” and that a preliminary report will be ready within 30 days of the accident.
Flight TM470 came down at around 13:00 local time in the Kavango region of northeastern Namibia.
It had been operating a route from Maputo taking it via the ANVAK and ETMIT fixes, entry points to South African and Botswanan airspace.
The flight left the Mozambican flight information region for South Africa at 09:34, and South African airspace for Botswana at 10:51, establishing contact with Gaborone radar.
It was cleared to operate directly to the AGRAM fix, which lies in a narrow strip of Namibian territory between Botswana and Angola. But it failed to make contact at this fix.
Botswana air traffic control has indicated that the aircraft had climbed to 38,000ft but began to descend rapidly, at a rate of some 6,000ft/min, before disappearing from radar below 2,000ft – at which point it had already crossed into Namibian territory.
None of the 33 occupants on board the twinjet survived the accident.