Takeoff separation?

[JamesT73J]

I flew out of Malaga recently on a 757 on what appeared to be a very busy morning, and out of curiousity I timed how long it took for us start our takeoff roll after a company 757 departed just before us.

Between the preceeding aircraft and our takeoff roll, it was almost exactly 60 (+/- 1 or 2) seconds. It seemed very slick to me; what are the actual guidelines?

[JustaFew]

Reading between the lines from numerous threads, the arrival/departure separation is everyone after Iberia......:)

[HEATHROW DIRECTOR]

That's rather a long time!! At Heathrow, provided there are no vortex or separation problems, they aim to get the next one rolling as soon as there is daylight between the wheels and tarmac of the one ahead. In reality it's very hard to achieve much better than a one-minute departure rate, but with a bit of work and cooperation from the crews it can be done... I recall one controller getting 15 away in 12 minutes once...

[mogley]

Wake turbulence spacing for dept are as follows:

Leading A/c Following A/c Spacing

Heavy Med/Small/Light 2 mins
(dept from same position)

Med/Small Light 2 mins

Heavy Med/Small/Light 3 mins
(full length) (intersection)

These figures are from Caa aic pink 188
:ok:

[caniplaywithmadness]

There are also specific departure separations that can be applied with departing aircraft where no vortex wake separation is required, (these are procedural separations)

I'm doing this from memory, so if someone out there has a pt1 handy they can correct me where I go wrong:

1 minute - if tracks diverge by at least 45 degrees immediately after take off

2 minutes - if first aircraft is 40 kts faster than the following and neither is allowed to execute any turns that will decrease this 2 minutes

5 minutes - If first a/c is 20kts faster than the following

10 minutes - all other cases


There is another 5 minute separation which involves tracks diverging by 30 degrees and other separation being applied but I can't remember the exact details



At EGPF I've seen a controller get 3 IFR departures away in the same minute, that would be 36 in 12 minutes and who says the controllers at LL are the best :p :p

[HEATHROW DIRECTOR]

CanIplay - what were those departures, all helicopters???!!!

The procedural departure separations aren't used much in a radar environment. Biggest problem is the noise abatement procedures, but if the routes are separated then, technically, as long as Vortex doesn't enter the equation, no time separation is necessary.

[caniplaywithmadness]

HD

it was a S340 followed by twin otter followed by ATP

S340 departed the intersection, twin otter the cross runway and the ATP off the main after the twotter through the intersection, granted it was all reduced separation in the vicinity but it worked well and all within the same 60 seconds

[JamesT73J]

Thanks for the replies. That's most informative. I've scanned various threads and articles about concerns with regard to wake turbulence and It got me thinking afterwards.

In a similar vein, I saw an amusing example of movement in the lounge at LGW. There were about six aircraft all waiting their turn in that wonderfully complex array of turn-offs near the threshold. Suddenly, a BA 737 appeared moving at a fair trot and swung round onto the runway at the entry point - in front of an aircraft that was already lined up on the runway. Someone remarked "Look at that little bugger - he's cut them all up!". I wondered what it was like for the a/c behind - he must have got a fair old rumble from the exhausts.

It's a testament to the people that coordinate all this - it just had me in awe. That and the two different lanes of taxiing traffic at the end of 26L, with several ways onto the rwy. It must be equally fun for the crews :)

[HEATHROW DIRECTOR]

CanIplay.. Brilliant, love it. Man after my own heart, without a doubt.

Take care..

James... Sounds like he was a bit tight with his slot time. ATC does its level best (not level bust!) to accommodate such things but it only works if there\'s room on the taxiways.

Sounds like you need a visit to Gatwick ATC to see how it all works. Don\'t ask me - they still hate my down there after a certain TV programme 20 years ago!!