Lhr ground question bit stupid but just curious!!

[twonk]

hey guys just quick question about a holding point in lhr rwy 27L N1/ NB1 why do u get all a/c to hold at cat2/3 hold ie N1 instead of normal cat 1? in normal operations,if u stopped at Nb1 beyond n1would ye guys be p!%$"d? sorry if stupid but always think about it when trotting on up to N1, thanks guys and nice job.


Twonk :ugh:

[Gonzo]

Twonk,

The idea is that asking you to hold at N1 instead of NB1 gives us more warning of a runway incursion. If you did cross N1 to hold at NB1, ATC would not know you were going to stop and would react as if it were about to be a runway incursion.

[Roffa]

Gonzo, by the same logic why don't we climb or descend to 2,000ft below the conflicting traffic instead of 1,000ft, just in case there's a level bust?

Even with SFL downlinked that's no guarantee, we don't know anyone is actually going to stop at their cleared level...

[Gonzo]

I guess the APSA process has determined that using the CAT II/III bars is a better safety v capacity balance than 2000ft separation....which nobody could deny would be a safer option if the traffic volume allowed.

Don't shoot the messenger, just relaying what happens. :}

I myself have some reservations, especially at night in CAT I conditions when the CAT I stop bar is lit...Yet we are recommended to clear a/c to the CAT II/III bar...is that possibly encouraging a/c to not stop at clearance limits? Discuss!

[timelapse]

I always thought it was because we couldn't be bothered to say the extra two syllables in each transmission :}

[arthur j negus esq]

[QUOTE]Roffa Gonzo, by the same logic why don't we climb or descend to 2,000ft below the conflicting traffic instead of 1,000ft, just in case there's a level bust?[/QUOTE

At some units it is "best practice" to use 2000 ft separation...

[HEATHROW DIRECTOR]

Where's that then, Arthur?

[twonk]

thanks for that gonzo was just curious is all,

[Silk Merchant]

Heathrow Broadcast . . .

Not wishing to contradict the Great Gonzo, but my reason for using the CAT 2/3 holding points is that "they" give me a pop-up on the electronic flight progress display for them. I just touch the hp box, touch the appropriate hp and, hey-presto, it appears on my display - all done with two taps of the screen. If I want to use a CAT 1 hp then

1) it is more to say (as has been mentioned) and more to listen to in the read-back (and more chance for the pilot to get it wrong?) and
2) I have to open the hp pop-up, touch the appropriate box to get a keyboard display, touch the appropriate letters to correctly spell the holding point then touch "Enter" to close the keyboard and finally touch "Enter" on the pop-up to get back to the normal display.

So, for me, it is a more efficient use of my time to use the pre-set buttons I am given. In a similar vein, just because I am not talking it does not mean I am doing nothing. I use the time when I am not speaking to plan the best order for departure and ensure holding point delays are kept to the minimum. Any intrusion on this thinking time eats away at my ability to get the best departure order from the runway. Something to think about next time you pilot chaps & chapesses decide to tell me you are at Pluto/can accept A6 and beyond/are listening out;)

SM
PS What is APSA, Gonzo

[timelapse]

What he said :)

[Gonzo]

SM,

Funny really, as the popup used to display the xBxx holding points, but people wanted to get rid of them.:}

ATC Procedure Safety Analysis

[mr ripley]

So as you say:
What about at night? It does seem odd to have the reds at the Cat1 hold. I presume there are reds at the LVP holds. Why aren't they used?

[timelapse]

The position of the bars will depend on the overall setting of the Aerodrome Ground Lighting system - the entire operation of the system would have to be changed to Cat2/3 for those bars to be illuminated. This would cause various problems with the lights if you were not in cat2/3 ops, especially on easterlies.

This would also change all of the wigwags all over the airport to the cat2/3 positions which is undesirable if you are not in cat2/3 ops!

I agree though that it isn't brilliant human factors to have you hold at one place but the stop bar be somewhere further along..

[Sir George Cayley]

It's been proposed that all runway holds should be at the CAT ll/lll location and that CAT l or Vis holds are dispensed with.

As a runway incursion defense initiative it seems to make sense as everyone stops at the same spot regardless and reaction times where there are 2 runways are not that affected.

Sad that such simplification is required for such an intelligent work force:\

Sir George Cayley

[mickrobbo]

I never thought using N1 instead of NB1 would prevent more runway incursions. My reasons were it was quicker to say, readback and again, write down/tap on EFPS. Same as N3 not NB3 if I remember rightly....my time in the desert has somewhat blurred the memory of the great LHR. Don't get me started on the CATIII holds out here...they have taken the 137m rule and multiplied by 6 for the fun of it :ugh:

Also I seem to remember most crews using NB1 when told N1 anyway, though pilots on line checks were good little boys and held at N1 :ok:

[M609]

Where's that then, Arthur?

Oslo TMA

It´s not used as a sep-minima, but used to ease the number of nuisance tcas RAs where certain SIDs cross STARs. (Badly designed tfc flow system, new stuff on the way) Less spurious STCAs in our system as well.

It´s a FL90/100 crossing, but we now use 90/110

We can use 1000ft if needed, but strive to avoid it. Everywhere else in the TMA, ops normal ;)

[tobzalp]

Gonzo, by the same logic why don't we climb or descend to 2,000ft below the conflicting traffic instead of 1,000ft, just in case there's a level bust?

This is a technique that is often employed where climb and descent are pointing straight at eachother in the higher flight levels with everyone doing the right thing. A couple of TCAS RAs is all it takes to convince most.
:rolleyes:

edit. Just saw a couple of others said the same thing.