Lambourne Stack

[Kolibear]

Its a wonderfly clear day here in South Essex and I'm looking out of my westerly facing window at work watching the airliners going round the Lambourne stack. Its more interesting than what I'm paid to do :)

What I was wondering was at what height are aircraft brought into the stack and what is the minimum height to which they will be descended? I've always assumed its above 2500' as thats the base of the LTMA at LAM Is there an optimum height at which you would be aiming to get the aircraft out of the stack and on route?

Does the size of the racetrack vary, as increasingly I'm seeing aircraft extending further to the east?

[foghorn]

Someone who is qualified will either confirm or correct me, but from memory the bottom level of all the EGLL holds is normally FL80 unless the QNH allows lower (LL SIDS usually go up to 6000ft).

From experience of being in the pointy end (back in the days when jumpseating was easy) they are normally vectored out of the hold at FL80 or FL90 and given descents once clear of the SID tracks.

[Jerricho]

Foghorn is kinda right. Depending upon what stack we are talking about can determine what the actual lowest useable is by who. All the SIDs from LHR climb to 6000'. When the QNH is 1013 or above, Min Stack is FL70 (eg today QNH 1030ish....). As the pressure drops below 1013, min stack changes (1012 - FL80) to allow for a higher transition level. However, who "uses" the min stack level and where depends on which hold we are talking about. The south stack, the EGLL Approach controllers "own" min stack, and descend stuff to it to come from the holds.

The north stacks are a little different. Due to the interaction of Heathrow, Luton and Stansted SIDs (and London City/Biggin Hill inbounds, and any others I have missed), there are designated points where the approach guys can descend to min stack, otherwise we stay at min stack +1 until these points are reached (these are runway dependent as well!). Ideally we try to come off the holds as low as possible, but sometimes you have to grab a bunch of jets to keep things running.

[Roger Dodge]

Couldn't have put it better myself Jerricho:D :}

[Jerricho]

R-D................I know!!!!!:E :E :E

[asw28-866]

Jerricho et al,

sometimes you have to grab a bunch of jets to keep things running.

Love it when you guys get all technical, just trying to prove a machine cannot do your job!

'866':p

[Topofthestack]

The extent of the holding area is usually a one-minute racetrack pattern but this is sometimes allowed to be extended to one and a half; anything further puts the aircraft too far away from the beacon and into another sector's airspace or conflicting routes. Once the aircraft leave the hold they're usually descended to 4000ft, which is above the SID intial climbout level from EGLC. When flights are within the appropriate distance from EGLL, they're descended to 3000ft to join the ILS.

As far as how high they go in, this will depend on the amount of traffic running into the stack in the same period. The stack can hold traffic upto FL170, and FL180 and above with co-ordination with the sector above, but that leads to separation problems with other routes: at FL180 and above, traffic is normally held back at BRASO and then brought on as levels become available at LAM.

[Fright Level]

When the hold is busy, it's common to ask for extended legs (time or distance). Holding above FL140 (if they're really busy) requires a 1.5 min leg in any case.