FullWings,
thanks for the reply,
I have no intimate knowledge of the TCAS algorithms, but my point was to see if this was a credible scenario:
- Two airliners, both with transponders, one with serviceable TCAS, the other unserviceable.
- On conflicting trajectories ("collision course")
- TCAS-aircraft gets RA ("Descend, Descend!"), complete with red area, possibly larger than in the case whin which the conflict is expected to climb, but I'm on shaky ground on this.
- Non-TCAS aircraft gets ATC-instruction to descend, but, significantly, does not get an RA. (With the instruction to descend to the next FL below, separation is supposedly restored, from an ATC point of view.)
This scenario is facilitated by:
- Lack of knowledge by ATC of RA
- Lack of knowledge by TCAS-aircraft flight crew of lack of TCAS in conflict aircraft
- Rules of dispatch for U/S TCAS unit (10 days, is it?).
If this isn't a clear hazard (read: danger) created by following an RA I don't know what is.
And for this scenario we don't even need to suppose one flight crew disregarding an RA, rules may well be for all operators to always follow the RA!
I'd be grateful for anyone to point out possible factual errors in this one, since I'm not familiar with TCAS internals and the exact conditions under which what kind of RA will be issued by TCAS on encountering a "dumb" target.
Bernd