Approach from lambourne hold

[boe777]

Hi, I would like to know if the aircrafts follow a path towards the final approach to heathrow once they have been vectored off the stack, ie; do they follow beacons ? I know that they normally follow S shape from Lambourne hold,passing just past Canary Wharf where both the stacks meet for the approach to Heathrow, this path leads just over my house, however lots of aircraft do short cut, ie they will bypass the greenwich and canarywharf and head over central london from the stack before joining the final approach. Also which airband freq would be best to listen to when being vectored off from lamboune stack ?

Thanks...

[wiggy]

No, they don't normally follow beacons, though there are back up procedures involving various beacons that can be used in the event of radio failures. Instead the Air Traffic Controllers normally give what are know as "radar vectors" once the aircraft leave the hold - i.e. headings to steer, which, combined with speed and altitude instructions should :} end up with a nice procession of aircraft down the final approach to the in-use runway at Heathrow.

Usually you do indeed fly a S shaped pattern off Lamborne if landing to the West at Heathrow but if it's not busy (e.g. early AM arrivals) then you'll get some sort of short cut - and the controllers can and do vary the routing depending on traffic....

[HEATHROW DIRECTOR]

Just to add to Wiggy's piece..... in busy airspace aircraft are under radar control before and after the holding facilities, such as Lambourn (there are 3 other Heathrow holding facilities). The radar controllers responsible for the airspace around London are located at the ATC Centre on the south coast.

Caution: It is illegal to listen to the airband, although information about such things is in the public domain... try Google.

[boe777]

Thanks Guys for the info, Its amazing just how complicated it can be for the guys in the ATC, taking into the consideration the diffrent aircrafts ie; A380, followed by 737 or a330, 777 etc, do they give instructions about the wake and turbulance that follows the heavies ? does the horizontal seperation increase after a heavy ? also does ILS vary for heavies and say a 737 or m89 for example, since the gradient will be diffrent...

Also while the aircraft is landing, I believe they are at maximum thrust..does that mean that the speed in reduced just with the help of airbrakes, aielrons and flaps ?

[simfly]

No they don't give instructions about wake turbulence, but they position following aircraft behind at a minimum distance to avoid the wake turbulance from the proceeding aircraft using headings and speeds. In a busy airport like Heathrow the distances have to be spot on, so they can move as much aircraft as possible. Aircraft are split into wake turbulence categories, Heavy, medium, small and light based on their weight, plus a special one for the A380! you are right that there will be a bigger gap behind heavier aircraft for smaller aircraft ie, 747 followed by 747 = 4 miles, 747 followed by A320 = 5 miles A320 follwed by A320 = no vortex issue, but radar seperation used etc, but where possible the controllers may try and group heavies together then smaller aircraft as this saves lots of larger gaps and gets more aircraft on the ground in a given time. The ILS "glideslope" does not vary, it is at an angle of 3 degrees. Aircraft use flaps to allow the aircraft to fly at a slower speed on landing, airbrakes / spoilers are used after touchdown to aid braking. With flaps & wheels down more power will be used on approach than if they were up due to the extra drag, but not full power, if it were then they wouldn't be able to go around. (ailerons btw are what is used to roll / bank the aircraft) That's a simplistic view anyway...

[wiggy]

simfly, I'm not sure the controlers do try to group arrival aircraft by wake category, from observation we are sequenced off the hold in turn from the various hold, irrespective of wake category, and then speed control/headings are given to achieve the required spacing on finals - any comment from the ATcers?

Anyhow you always end up with "160 to 4" at some point, and boe777, we definitely do not land at anything like maximum thrust.

[HEATHROW DIRECTOR]

wiggy.... They do (or they did when I was there) try to group the various weight categories to achieve the best landing rates. So occasionally an aircraft will be taken off the stack out of turn EAT-wise to provide a better landing sequence. A great deal of time would be lost if this procedure was not followed.

[boe777]

Hmm.. Interesting, so are they (engines) at say 70% of max thrust while landing? the reason i thought they would be at max was in case you need to abort landing at the last moment, ( i saw AI 777 do that just recently at heathrow, very low and almost ready to touch down )then atleast you can utilize all that power quickly. As pilots do you think an abort exerts more stress to the aircraft frame ? and if in case of aborted landing are they given any prefrence by ATC....

[HEATHROW DIRECTOR]

<<and if in case of aborted landing are they given any preference by ATC....>>

Unless there is a fuel problem, not usually. They're just fed back into the approach sequence and usually land about 10 minutes later..

A pilot will, I am sure, provide factual information... but the engines are throttled right back on landing. If the engines were wound up the aircraft would go off the end of the runway!

[simfly]

an F-18 landing on an aircraft carrier however...(or any other a/c landing on a carrier with a hook) does go to max thrust at touchdown incase they miss the wire, but that's coz there's not time to react if they waited to find out:eek: Are you maybe confusing it with that? As commercial a/c are producing still quite a bit of thrust on final approach, they will spool up to max power for a go around fairly quickly, might take a bit longer if the engines had been back at idle though, but I have witnessed an A320 go around after not touching down half way along a very short runway in a snowstorm, and it climbed away very quickly I assure you!

[potkettleblack]

To answer the thrust question we would typically be at around 55% as a general rule of N1 over the numbers in an A320/1. Bit less if we are light and a bit more if heavy. Never anything like 70% though. The spool up times aren't an issue for a go around. There is bag loads of thrust and if anything you will often find yourself having to pull the levers back so that you do not bust the go around altitude and over speed the flaps.

[HEATHROW DIRECTOR]

Hi John R. As already mentioned, and what many people do not seem to appreciate, is that aircraft flying into major airports are under radar control. I.e they are in radio contact with air traffic controllers who effectively handle the navigation from the ground.

The aircraft goes around.... shortly afterwards it is instructed by the Tower to contact the radar controllers who direct it back into the approach sequence by issuing headings, speeds and altitudes for it to fly. This usually means a turn on to the downwind leg to join the landing stream.

If the go-around was because of very bad weather ATC may well climb the aircraft back into one of the holding patterns where it will hold to await weather improvement. This prevents congestion at lower altitudes. In such conditions ATC will often keep the lowest levels in the holding patterns available.

Occasionally an aircraft flying a go-around may be very short of fuel. In an extreme situation it may be necessary to break another aircraft off the final approach and slot in the one which flew the go-around. Luckily this does not happens too often!!

HTH

[HeathrowAirport]

I suppose if it helps and no Im not a controller but for 27s Aircraft generally leave Lambourne heading 280*-260* generally and then turn left at about 8-12 miles on a heading of 90*-120* they will then be turned base at 170*-190* to establish at 10-15DME on a heading of normally 245*

[wiggy]

Interesting, I'd never noticed the arrivals sequence being tweaked in that way so I assume the process must be fairly transparent. Must pay more attention in the future....:ok:

Rgds

[betpump5]

boe777,

also we give the Director some information to help them categorise us: I.e "Pprune Airways 123 is a 744 with Information Alpha" etc.

That way, providing it is not too busy, the nice Director may sometimes give us heavies 230kts leaving the hold rather than 220. Flaps too early sure uses up fuel!

[Skipness One Echo]

Actually the fun bit is that when you see heavies descending Southbound onto base leg coming round the Wharf watching a 146 heading out of LCY climbing straight towards the descending heavy! Is very entertaining from Greenwich Park on a sunny afternoon.

[boe777]

betpump..
"Flaps too early sure uses up fuel!"

I may sound totally naive, with my muniscule knowledge about aircrafts, but do you guys have mpg for each engines ? and if the engine is replaced does that change the fuel consumption, I know things like using flaps, wind and ultimately the route decides how much fuel is consumed, most heavies carry a swimming pool, is the justification needed for every flight ?

Thanks

[boe777]

Skipness one echo, agree with you entirely, Greenwich park is an absolutely stunning place to be, the best view of London skyline and the point where both the stacks meet...recommend to anyone who enjoys a bit of spectacular scenery... shame about the cutty shark though...

[potkettleblack]

We don't have mpg as such but we have fuel flow per engine/hr and in total plus total fuel on board/used and also fuel pages that we can pull up which shows the total fuel remaining in each tank.

With the current price of fuel it is in everyones interests to conserve as much of it as possible. Things like flying clean (ie: no flaps out) around the holds and delaying the extension of gear and landing flaps till as late as possible in the approach all helps. In the event of a go around having as much fuel on board as possible will obviously be of benefit in shooting further approaches and avoiding a diversion.

Some aircraft/airlines will be tankering fuel in order to reduce turn around times and to avoid uploading "expensive" fuel at a destination so having enough to get you home plus reserves becomes a factor.

[HEATHROW DIRECTOR]

<<the point where both the stacks >>

It's actually where the traffic from four stacks meet!

[boe777]

Heathrow Director,

I was under the impression, they only use lambourne and biggin while the approach is on 27L/R passing over london, and they use other 2 stacks when "tresspassing on Queens abode "... never thought we have 4 stacks in use together.

[HEATHROW DIRECTOR]

boe777.... As John R suggested, there are 4 stacks in use all the time. Traffic from Scandinavia, Germany and various points east goes to Lambourne; traffic from Scotland and the north to Bovingdon; traffic from France, Italy and the southeast goes to Biggin Hill and traffic from the southwest and west goes to Ockham. Traffic at Bovingdon and Lambourne are on one frequency whilst that at Biggin and Ockham are on another. When the aircraft have left the stacks and commenced descent they are all then transferred to another frequency for final vectoring.

[togsdragracing]

This not not unconnected to the above so can I ask: if I understand it properly, then "intercepting the localiser" means that the aircraft picks up a narrow radio beam from the airfield which guides it in.

How narrow is that beam - can you be a mile left or right of the centreline and still pick it up? Or have I misunderstood the concept (or the physics).

[betpump5]

most heavies carry a swimming pool, is the justification needed for every flight ?

Boe777,

I'm a little lost.

Am I to assume you are using an analogy that we carry a lot of fuel? Hence the swimming pool?

If so, then yes there is a justification. The fuel is calculated based on many things and don't forget the extra fuel needed for diverting and holding. We don't just carry fuel for the sake of it.

If I am wrong and you really do mean that we literally carry swimming pools, then I'd tell you to get your face out of the Private Owners' A380 Brochures.

As for mpg, yes we do have have them for our engines. Urban, Extra-Urban and Combined. I usually get about 1 centimetre per gallon at Take-off for our RR engines.

[potkettleblack]

togsdragracing - everything you ever wanted to know about an instrument landing system.

Instrument landing system - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Instrument_landing_system)

Nicer picture of one here:-

Dictionary : Instrument_Landing_System (http://www.centennialofflight.gov/essay/Dictionary/ILS/DI87G1.htm)

[boe777]

betpump5,

I only wanted to glean, just how do the pilots calculate the optimum fuel reserve needed before each flight..

and potkettleblack has explained it well

We don't have mpg as such but we have fuel flow per engine/hr and in total plus total fuel on board/used and also fuel pages that we can pull up which shows the total fuel remaining in each tank.


Also, if the engines are replaced due to maintainance etc, does that affect the consumption.

as far as A380 is concerned.. you may soon have Burger King or KFC in arcade for PAX.. who knows.

[togsdragracing]

Question answered, thanks potkettleblack.

Back to enjoying lurking :)

[boe777]

then I'd tell you to get your face out of the Private Owners' A380 Brochures.



It would be great, to be in league of Gates, Mittal etc etc lol:)
i bet they will struggle too...