LHR Stack swap

[Thunderbug]

Twice in the last week I have been on flights that have been stack swaped from LAM to BIG. 2 different days, different time of day. On neither occasion was LHR particularly busy (5 min at BIG), but it seems strange to have this twice in a row after many years of never having to do it.

It's not a problem and I know you ATC guys prefer to stack swap the locals rather than the Air Kabul - but is there a reason behind the sudden emergence of this procedure?

Cheers!

[IThink]

Yep, the 15 other aircraft in front of you steaming into LAM. If the hold goes too high, outer holds have to be used which increase complexity and cause problems for TC and Swanwick.

Been happening for a few years and gradually becoming more common, it's just tactical traffic management.

[HEATHROW DIRECTOR]

I wasn't aware that any preference was given to "locals". You ought to see how it works... Near the Heathrow suite at TC there is the Traffic Manager position. There's a radar display there, set to about 100 miles range, showing only Heathrow inbounds. The TM simply counts the a/c heading for, say LAM, and decides that x is enough... so the next one gets stack swapped. There ain't nothing super-scientific in it and I don't know anyone who is biased towards "locals". If BNN fills up we get a lot of US airlines moving down to OCK.

[Captain Windsock]

Stack swapping has been going on for years so is nothing new. It's a bad idea to have all the aircraft in just one stack with the other ones empty or almost empty. If the bottom one at LAM goes to sleep at least there's the oportunity to snatch someone else so we don't lose any landing slots. It happens all the time that the delay might well only be 5mins but all the aircraft are destined for the LAM stack.

[MacDoris]

As Lam tends to be the busy stack it is usually the one to experience stack swaps, usually to Big if its traffic permits, if possible we try not to switch airlines which may not be used to the procedure of have greater difficulty understanding us when we try to explain what is going on, there really are only a few airlines this applies to, its not a jump the queue type thing, it will depend on your position in traffic through Logan, other traffic around you to Gatwick etc all this is considered.

Just recently we have even swapped from Lam to Ock which is quite interesting.

Its just about keeping the inner stacks full and keep the en route holding to a minimum.

[eyeinthesky]

Another point is that it is easier to explain to a BMI or BA pilot that they will need to swap stacks and have different levels to make than it is than to an Air China or Uzbekistan Airways, for example.

There should be no benefit to either party as the EAT (if there is a formal one or not) from one stack should be transferred to the other.

[tired]

Totally off the subject, for which my humblest apologies ,but why is it that sometimes I hear 2 different controllers on the same frequency controlling 2 different stacks? Seems to happen often when I'm going round the LAM or BIG holds that I hear traffic in the other hold being controlled by a different ground chappie/ess? Or am I imagining things??

OK, now you can go back to the original topic!

[Warped Factor]

tired,

Probably most likely on 119.72 working BOV and LAM.

During peak periods the radar controller will have a support controller plugged in beside them.

Radar man does all the vectoring off the stack and around the houses plus descending to altitude type stuff.

The support controller looks after the telephones and usually does the answer to your initial call and the laddering down the stack type stuff.

134.97, BIG and OCK, can also be shared by radar and support as well if necessary, but not done very often.

Also, when we've got one radar person working all four stacks during the day at relatively quiet times, it is more than likely they'll have a support person beside them sharing the freq as well.

It's a bit of an art not stepping on each other at times

WF.

[tired]

Thanks, WF, now I understand.

t