I was thinking about a hypothetical (and thoroughly unlikely, but possible) scenario the other day, and I was wondering how TCAS would handle it:
Three aircraft, A, B and C, the type doesn't matter but they are all airliners, all equipped with the same version of TCAS.
Aircraft A is climbing through FL 355, aircraft B is cruising on FL 360, and aircraft C is descending through FL 365. Their flightpaths will converge essentially on aircraft B at FL360.
How does TCAS respond to this? Will it recognise the three way conflict, "talk" between all the transponders and then issue RA's agreeing with the other two aircraft (e.g a/c A will recognise a 3 way conflict, the crew will receive an RA to descend, a/c B to maintain vertical speed, and a/c C to climb), or will each TCAS on the different aircraft only recognise it as a "normal" two way collision, and react to only one of the conflicts? In this case, I guess a/c A would still receive an RA to descend, and a/c C would get one to climb but would a/c B get one to climb/descend, disregarding one of the two aircraft?
In this case, (let's say B gets an RA to climb, the TCAS only recognising a/c A as a conflict) once it was clear of conflict from aircraft A, would the crew get another RA telling them to descend, this time in relation to aircraft C?
Was just wondering if TCAS was designed with a three-way contingency in mind.