Originally Posted by
vapilot2004
It takes two (transponders that is) to tango with TCAS - what about the other guy ?
BBC report 'smaller aircraft' to be a Embaer Legacy (Brazilian aircraft similar to Learjet 45) which would have TCAS (Traffic Collision Avoidance System) mandated by ICAO to be fitted to all aircraft over 5700 kg or authorised to carry more than 19 passengers.
As with most aviation accidents the cause is likely to be a chain of events and failures leading to collision.