joernstu,
If you look for more evidence you will find complains of ATC on a device that manipulate the outcome of their instructions, leaving them without a coherent image of the situation in the air.
If I'd set two aircraft on a collision course in error I'd
want something to manipulate the outcome of my instructions! Never heard/seen any complaints myself, especially from people who understand how the systems work.
Another problem with TCAS is that the manufacturer (and following him many other organisations) present TCAS as a technical solution in a conflict situation where every other means to avoid a collision have failed. In the Ueberlingen mid-air TCAS gave an RA when both a/c were at 7.11 NM seperation. The limit for seperation in this airspace at this night was 7 NM, usually 5 NM. This demonstrates that TCAS can act at points in time, where other means have not yet failed, rebuting the claim that TCAS only acts when everything else has already failed.
OK, RA given at 7.11NM, limit 7NM. Time to close 0.11NM was less than a second, so loss of separation was assured as no realistic course change could be made in that timeframe.
TCAS only knows what is happening, not "intent" (maybe in the future with mode-s, etc.) It has to assume there will be no outside intervention and I think 20-30s before collision is not unreasonable. In the event under discussion, primary means of separation had or were shortly going to fail so the secondary systems started to activate. There is inevitably going to be an overlap between the two but in the example above it's very small.
More theoretical arguments are multiple aircraft situations (for which it can be proved that TCAS cannot give advice solving the collision threat) and aircraft without transponders.
And these cases form what percentage of the threat population in an ATC radar environment?
Of course TCAS is better than nothing (at least I hope that this is the case as it was certified for use in aviation), but I also get the image, that it is still far from optimal.
At least we agree on something.
