"News" is beginning to seep out. On a local aviation forum there's the following (free translation):
According to a CAB specialist the American Legacy pilot said, during the post-accident debrief, that he'd decided to climb from FL370 to FL390 to gain speed and range, without informing ATC, and that he'd switched off the transponder (for reasons unknown). That would have impeded the 737's TCAS from reacting to the Legacy's presence and delayed ATC's warning that a collision was imminent since, with the transponder off there would be a lag for radar to correctly track the Legacy.
Please note, a very free translation, picked up second-hand. The original text follows for any who might care to dispute it:
Quote
Segundo um especialista da Aeronautica, no depoimento, o piloto americano do Legacy disse que teria decidido subir do FL370 para FL390 para ganhar autonomia e velocidade e não teria avisado o controle da força aérea e também desligou o transponder (motivo desconhecido), impedindo assim que o TCAS do avião da Gol funcionasse e que os controladores pudessem avisá-lo com antecedência do choque iminente, visto que com o transponder desligado o radar demora para obter informações da aeronave.
Unquote
Along with all the unbiased speculation surrounding this accident there will undoubtedly be an increasing element of biased speculation, with blame thrown about, particularly when the lawyers get involved. The Legacy crew will be at the centre of this. Don't, however, knee-jerk and write off the above as the beginnings of an ass-covering exercise; assume that the debriefing people would have most likely have been airforce, pilots, fluent in English and focussed only on gaining whatever knowlege/insight was available as quickly as possible, without regard for blame. Keep that in mind; ass-covering will come soon enough.
And, just speculation on seeing the first aerial photos and what seems like absence of fire: if the aircraft went in pretty much vertically from fl 300+ as some reports have said, it could well not have been intact at all, i.e. little fuel in the hot parts. Whatever explosion there might have been would spread outwards and, in a wet forest of trees 30+metres high, leave little evidence visible from the air.