I must conclude that due to history, that mention "acquire visual" is still here but shouldn't be and pilots not aware of the new philosophy (most of the time not thorougly mentionned in operation manuals") might still use their own perception to go against RA orders, right ?
nice isn't it ?
Cruised into this thread fairly late, courtesy of the 'similar thread' funtion.
The problem with all of this is trying to apply a 'one size fits all' philosophy to collison avoidance.
Yes, its true, manouvres should definitely not be made solely on the basis of TAs.
It is however entirely possible that getting a visual spot on the other traffic might save the day.
What's needed is a sound appreciation of the relative merits of how you can avoid hitting another aircraft. Sometimes a turn is a sensible option, but it needs to be based on a visual spot rather than the traffic display.
Before someone jumps in and says that this suggestion is insane, and then gives an example when it would be, I accept that. The point is that one size does not fit all, and the suitable options depend on the circumstances; including of course that if an RA is given it must (if possible) be followed and must certainly never be manouevred against.
The most obvious example of a situationwhere a turn should be flown is the non altitude reporting intruder. On my 3rd most recent flight, a light aircraft blundered into my approach path. It was not altitude reporting. It was observed on the TCAS TD, and on that basis spotted visually, and on that basis I was just about to manouvre when it beat me to it (rolling on 80 degrees AOB and pulling like a bastard!). If it hadn't manouevred, and I had not spotted it, but rather just concentrated on my PFD waiting for the RA that was never going to come.....
People should receive theoretical training in the judgement of visual manoeuvres, for 2 reasons:
1. For the scenario above.
2. To learn how useless we are at judging vertical manoeuvres; to provide additional understanding of the reason why an RA must not be second guessed, thus reinforcing the need to follow RAs.
In summary the reasons for attempting a visual spot are valid as part of an overall strategy for collision avoidance. The reason its suggested is just as valid as the reason why an RA must be followed.
pb