TCAS Avoidance

[Speedbird744]

Concerning TCAS alerts,
If pilots monitor any other traffic on their ND's. Why are there some many near misses? If there is TCAS alerting the pilot, why can't the pilot avoid it in advance????

[AYLGR]

1. Not all a/c have TCAS or transponders
2. Not all heights are verified
3. Level busts
4. Poor ATC separation instruction
5. Pilot error

Any more?

Bob

[AffirmBrest]

6. Not all TCAS aircraft have a nice ND with Traffic display
7. Pilots have more important things to do in the TMA than stare at the little blips all the time
8. We do not maneuver based on proximity or Traffic alerts alone, to do so would cause all sorts of problems with co-ordination of the TCAS in the aircraft concerned, with other a/c in the vicinity, etc. Watching the blip may prompt a pilot to query something with ATC but you just cannot take your own evasive action based on the traffic display, particularly in CAS. We should NEVER make avoiding manuevers based on the lateral position of displyed traffic - simply because the accuracy is not high enough to be safe.

I see a bit of a nonsense in your question (not being rude - honest!) - the whole point of TCAS IS that pilots make co-ordinated manuevers in advance of a COLLISION. That's what TCAS alerts do. There would be little benefit in manuevering just to avoid an ALERT, when that would cause workload problems for all concerned, and possibly conflict with other aircraft in the TMA.

And besides, define 'so many' near misses?
Much of the sensationalist world media would suggest that a correctly carried out TCAS manuever is a 'near miss', when in fact it actually PREVENTED one! SO pilots DO avoid near misses by manuevering in advance!

And who says that a responsibilty of the pilot is to 'monitor any other traffic on their NDs'? Sounds lke the responsibility of Air Traffic (though of course we all do the best we can) - see item no. 7.

Hope my ha-pennorth gives food for thought...

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...proceeding below Decision Height with CAUTION...