A classic case of the holes in the cheese lining up I think
IF the ATC controller had known about the Sukhoi demo flight
IF the weather had been marginally better
IF the pilot had taken the same route as he did in the morning
IF they'd flown from Sukarno-hata and not Halim......
etc ewtc
any one of the above could have saved them
actually looks like quite a good report as well -I thought they'd at least whitewash local control.......