Tcas Ra's In The Hold
 

Just a quick question to either ATCO'S or Pilots,

if an aircraft gets a TCAS resolution advisory whilst in the hold, what is the correct procedure to be carried out.

What affect does this have on ATC OPs? :{

Cheers

Seen this happen first hand in the Bovingdon hold for Heathrow (How are at Hammy ;) ).

All you can really do is pass traffic information like there's no tomorrow and wait for the drivers to tell you what they are doing and when the manoeuvre is over.

Follow it, and er shall we say interesting

During winter (and associated snow clearence holding) 2000ft seperation in the hold is neccesarry some places up in the far north, because turbulence from terrain cause a lot of vertical movement in the stack from time to time.

'Someone' experienced this on a snowy moring many moons ago when TCAS was just introduced:

5 a/c in the stack (yes not much, but still)

Nr.3 from the bottom gets caught in a downdraft, and decends a lot.
Same time, bottom a/c gets caught in the same downdraft.
Nr.2 from bottom get's RA from Nr.3, and Nr.1 gets GPWS climb from terrain below, and climbs, giving Nr.2 RA climb, and Nr.3 RA climb.

Now, nr.4 did not have TCAS.....so it did not go any further.

Still..... :ugh: :uhoh:

As above really, pass traffic info and if an a/c in the middle reports descending maybe give avoiding action turns to the a/c below that aren't yet in response to an RA