Originally Posted by songbird29
Furthermore, how can knowledge, acquired by a downlink, be confusing. It is lack of knowledge and bad decisions taken based on a lack of knowledge, which is confusing.
One scenario I can think of and where this would be problematic is a situation between one aircraft with transponder and TCAS and another without with ATC providing separation.
If aircraft 1 (the one with TCAS) for some reason deviates from its flightpath towards the flightlevel of aircraft 2 and almost simultaneously its TCAS transmits a bogous RA to ATC, the controller will not advice aircraft 1 to return to its flightpath as heshe would see the TCAS RA indication on the screen and could miss to recognise that aircraft 2 cannot be the cause for the RA.
So perhaps for downlinking TCAS RAs in addition to transmitting only real RAs (those issued to the crews), ATC would also need a database on all aircraft listing their transponder state. This database itself could introduce other failure scenarios.
The indication of TCAS RAs to the controller has to be correct 100% when it is made - or the indication should not be made at all.
Reason for this is, that no indication made at all will not change the current situation where ATC and TCAS simultaneous try to control the aircraft - not changing the current level of safety. TCAS RA indications to ATC which aren't 100% correct could lead to controllers acting as though they were 100% correct but in those cases where they aren't lead to dangerous or fatal situations - in extreme lowering the level of safety instead of improving it.