Why was TCAS priority the point of failure? As I understood it, the TCAS said the correct thing to both aircraft, but the ATC overrode it in one, resulting in the accident.
Technical in the sense of giving priority one over the other; the priority was clear in the US but at the time not strictly set in Europe or Japan (a near miss happened one year before because of conflicting instructions) and in Russia the opposite (highest priority ATC) was true with TCAS being a new thing obligatory for flights to Europe, of the five crew members only one pilot seemed to be aware that the two TCAS are tightly coordinated (CLIMB/DESCEND) for a last resort, but nobody listened to him.