Changing ends

[simonhk]

Hi all,
How do you go about changing runway operations for wind direction? I'm guessing that in places like the south UK all the airports have to "flip" at the same time. So what process do you go through? Or do you just flip a big switch somewhere
Do you end up with the last arrivals on 27R facing the first arrivals on 09L?

SimonHK (SLF, ex ppl, simmer)

[radar707]

Hi Simon,

Changing ends is a relatively simple operation, there are many factors that determine the runway in use, surface wind being the main one, but we also have to consider the upper winds, if the surface wind is say 200 @ 5kts then you might think that the westerly rwy would be best, but if the upper winds are:

3000ft 010 / 38
2000ft 090/ 25
1000ft 100 / 25

then the minor tailwind on short final by using the easterly runway makes it a lot easier than having a large tailwind on the approach.

Other things to consider are serviceability of Nav aids, ILS category, even the position of the sun (especially if the upper winds favour neither end).

Once we decide to change ends, we either wait for or create a gap in the inbound and outbound traffic, switch the ILS to the correct end (just the turn of a key ay Glasgow), change the lights so that all the corrrect lights are on for the runway in use, inform all the relevant people (Usually airfield operations, Fire Service, Satellite airfields, any contractors working on the airfield), then we start sequencing fo rthe new runway.

All very straightforward until you get pilots who can't accept the surface wind when the upper winds favour the rwy in use and they want to depart from the wrong end, which happens quite a lot at Glasgow due to the peculiar winds we have around the airfield.

hope that helps

[vintage ATCO]

No, the southern airports don't change at the same time, the wind could be significantly different at each, and besides Stansted have a NE/SW runway whereas the rest of us (mainly) have E/W.

At Luton we agree with the Intermediate Director (at TC) after which inbound we are going to switch, keep the outbounds going to the old runway until that time, then make sure we have the outbounds going to the other end afterwards. :D:D Tell all the people radar707 mentions and some besides, throw all the switches, get a radar release on the first departure off the new end, and Bob's your uncle!


VA

[Captain Windsock]

Radar707 says

"Changing ends is a relatively simple operation"

Well it wasn't simple the other day at Heathrow when the last but one departure on the old runway aborted take off which resulted in immediate entry in EAT's.

[Jerricho]

While LHR has 27L & R as "preferential" runways, to share the noise around there is a published list of dates and runways alternations to be used.

It isn't uncommon (especially at the moment with all the work being done during the night) to be using one runway (say 27R single), then if the work is finished in the wee hours of the morning, that the other end is officially the one that should be used (taking into account wind direction and strength).

[simonhk]

thanks all,
I remember seeing a BA 146 turning an easterly approach to London City, and an Emirates 777 turning for a westerly approach to LHR.
I wondered what was going on, they looked like they were pretty close to each other (of course, they weren't really). All looked very balletic ;)

BTW, what's EAT's?

SimonHK

[RomeoTangoFoxtrotMike]

I remember seeing a BA 146 turning an easterly approach to London City, and an Emirates 777 turning for a westerly approach to LHR.

Dunno about it being a BA, but easterlies into LCY while LHR is on westerlies is not an entirely uncommon sight as I walk home from the tube.. :) and they do look much closer than I know they are :uhoh: :ok:

[av8boy]

"Changing ends is a relatively simple operation"

Well it wasn't simple the other day at Heathrow when the last but one departure on the old runway aborted take off which resulted in immediate entry in EAT's.


I started to pen a similar response but when it began to look like a novel I thought better of it. In short, there are a good many locations at which "turning the airport around" results in bleeding ulcers for many, and for those operations where one runway configuration is used 97% of the time, a switch can REALLY slow things down...

Just ONE illustration: consider an airport with a 10,000 foot east/west runway where the prevailing wind is from the west and blows from the east only a few days per year. Assume that the designers put the tower near the approach end of 27 (with good operational reason). When runway 9 is in use, the controllers find themselves close to two miles from the threshold, making it very difficult to get the most efficient use possible out of the runway.:uhoh:


Dave

[Jerricho]

Hey Simon,

EAT's are "expected approach times". Aircraft pilots are issued these times when the delay for holding in the stacks is above 20 minutes. Without going into the specifics, it gives the pilots obviously an indication of how long they are going to be holding for (which can be critical in some jets that have flown for 13 hours and have a low fuel situation) or in the unlikely event of an aircraft having a radio problem, the pilots knows when to commence an arrival procedure, and we as ATC having recieved acknowledgement that the pilot has this EAT, know when the will commence and approach (and get everything out of his/her way).