PPRuNe Forums - View Single Post - TCAS selection to TA only
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Old 22nd Jan 2001, 23:45
  #11 (permalink)  
Capt Pit Bull
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ortorotel,

Too right. TCAS cannot gauruntee to solve every encounter possibility, hence the purpose of the Traffic Display - to get your eye on the intruder, so you can turn based on a visual spot (or if an avoiding turn is offerered by ATC). A turn is definitely worth considering, as long as it is not based solely on the Traffic Display.

max lenz.

The normal SSR frequencies - 1030 and 1090 MHz.

I don't follow your comment about 'choas must be complete'. Do you mean the idea that all the aircraft have to keep track of one another?

Very brief explanation - TCAS uses the mode S address (which, crucially, is unique) of the intruder to maintain a 'Roll Call' list of those aircraft it is worried about.

Its datalinking transmission are (a) directional (b) at the minimum power level required to establish contact (c) done only as often as is required in relation to the level of threat, and (d) contain the mode S address of the aircraft being contacted, so are ignored by every other aircraft.

They alternate this with a general scan of the area using 'mode c all call' which is ignored by mode S aircraft.

If you would like more info, let me know.

I don't actually believe that a pilot needs to know all these details, so long as they are prepared to follow the manufacturers operating instructions. But if a pilot wants to know why the checklist is the way it is, (or even to second guess it!) then clearly more research is required.

Also I'd like to second your point about reducing climb rate when approaching cleared level. Particularly, if you get a TA as you approach your clearance. This means you are in (or very nearly in) the triggering parameters horizontally, so moderating your vertical speed is a good idea and saves a load of paperwork! It also completely above board as long as you are not breaking your clearance (i.e. maintain at least 500 fpm).

CPB