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Mstream
15th Aug 2006, 09:56
Hi all ATCOs !
What kind of departure separation do you use at your airports ? Time (number of seconds between take-off clearances), distance (preceeding has to fly away x miles from the airports) or any other ?
Of course I am not asking about situations where wake turbulence is an issue but for example about sequence of medium category planes in a departure sequence.

Dizzee Rascal
15th Aug 2006, 15:31
So are you asking about IFR Departure Separations or Vortex Wake Departure Separations?

Gonzo
15th Aug 2006, 16:27
Dizzee,

So are you asking about IFR Departure Separations or Vortex Wake Departure Separations?

I think this covers it...

I am not asking about situations where wake turbulence is an issue but for example about sequence of medium category planes in a departure sequence.

In the UK we separate by time.

Barnaby the Bear
15th Aug 2006, 19:09
Ready?

1 minute-Provided that the A/C fly on tracks diverging by 45 degrees or more immediately after departure

The minimum may be reduced when A/C are taking off from independant diverging or parallel runways provided the procedures have been approved by the CAA.

2 Mins - Provided preceeding A/C has filed true airspeed 40 kts or more faster than the following.

Neither A/C is cleared to execute any manoeuvre that would decrease the 2 min separation between them.

5 Mins - Provided the preceeding A/C has filed a true airspeed of 20 knots or more faster than the following aircraft.

5 Mins - Provided that the 5 minutes separation is maintained up to a reporting point, within or adjacent to a control zone or terminal control area, and the A/C will subsequently be separated either:

a) Vertically

b) By tracks which diverge by 30 degrees or more, or

c) by Radar

Only to be used a locations approved by the CAA

Or else 10 minutes


* Separation minima based on time cannot be acheived unless the whole sixty seconds of each minute specified is permitted to elapse


Thanks to MATS pt 1. :8

airac
15th Aug 2006, 19:55
RTFQ Dizzee:ugh:

foghorn
15th Aug 2006, 19:59
Ready?
1 minute-Provided that the A/C ... Thanks to MATS pt 1. :8

But then there's speed tables as well at those units whose MATS 2s allow it.

Mstream
15th Aug 2006, 20:39
5 minutes ... or else 10 ? Isn't that procedural separation ?
I am asking about departures being radar controlled after departure (radar APP).

vintage ATCO
15th Aug 2006, 21:28
We use speed tables. 2 mins between aircraft in the same speed group, add an extra minute for each speed group difference when the first is in a lower group. On some routes where there is a split we can use 1 min. In practice, we are allowed to use the ATM to achieve 5nm in trail, just watch the speed groups. :)

Barnaby the Bear
15th Aug 2006, 22:26
5 minutes ... or else 10 ? Isn't that procedural separation ?
I am asking about departures being radar controlled after departure (radar APP).

I just answered your original question.
Didn't want to go into speed tables. RSI just from typing that lot before.
:(

Mstream
15th Aug 2006, 22:28
If it would be possible to get just few examples from such speed table I would appreciate it very much.

Mstream

Scott Voigt
16th Aug 2006, 01:15
DFW uses one minute between departures if you can't use visual separation on them with courses diverging by 15 degrees. If it is VMC and no wake turbulence is being worried about we can launch a jet behind another one when the first one is at least 6000 feet down the runway and airborne...

regards

Scott

GuruCube
16th Aug 2006, 07:29
Im sure I replied to this yesterday but my response seems to have disappeared?! Hmmmph. :hmm:

foghorn
16th Aug 2006, 08:59
If it would be possible to get just few examples from such speed table I would appreciate it very much.
Mstream

It roughly goes like this:

Group 3 - Jets with a few slow exceptions
Group 2 - Fast turboprops, slow jets
Group 1 - Turboprops.
Group 0 - Pistons and very slow turboprops (e.g. SH36)

If routes track 45+ degrees apart after departure, 1 minute separation.

Otherwise separation is 2 minutes or for some interacting routes 3 minutes.

Then if the slower type is first, add the difference between the groups on the speed table e.g. piston followed by a jet = 2 + 3 = 5 minutes, turboprop followed by a jet 2 + 2 = 4 minutes.

However if the following aircraft is more than 2 groups slower than the preceding one then the overall separation is 1 minute e.g. Jet followed by Turboprop = 1 minute

The details differ from unit to unit based on local experience and of course vortex overrides these.

no slots
16th Aug 2006, 11:52
Hi all ATCOs !
What kind of departure separation do you use at your airports ? Time (number of seconds between take-off clearances), distance (preceeding has to fly away x miles from the airports) or any other ?
Of course I am not asking about situations where wake turbulence is an issue but for example about sequence of medium category planes in a departure sequence.
We use the tried and tested 'CALENDER' seperation at our airport.1 on monday,1 tuesday etc.Cant get safer than that!!!

Barnaby the Bear
16th Aug 2006, 17:02
We use the tried and tested 'CALENDER' seperation at our airport.1 on monday,1 tuesday etc.Cant get safer than that!!!

I hope you comply with SRATCOH!!!!!!! :zzz:

Gonzo
16th Aug 2006, 17:15
Speed groups....Yep, the only Group 4 we have now is on the front desk! :{

choclit runway
16th Aug 2006, 17:46
Just launch 'em..... Radar can catch!!!!:=

Ready Immediate
17th Aug 2006, 08:13
I personally love the:

"If he can catch him he can $&#@ him" standard.

RI

Tarq57
17th Aug 2006, 23:27
Departure seperation here is delegated to tower via a simple to understand formula we have nicknamed the suduko charts.
There are 4 bands of performance based lines. We use 2 and a half miles in-trail for aircraft in the same group, 1 and a half for anything slower following a Boeing or Airbus, Runway length following observation of preceeding a/c turning 30 degrees, observation of a turn on radar where the blip has cleared the departure track, "adequate seperation" where one (or more ) of the a/c are on a visual departure, preceeding aircraft above 4000ft (4500ft where the 2nd is faster) plus since we have to protect the missed approach when wx below circling (for a category, or all categories) there is a chart of required distances the departure has to be rolling by depending on what performance band the departure (and the arriving) a/c is in. Typically 4-7nm, up to 12 nm eg; for a Seneca departing ahead of a Boeing on final.
There are permutations which vary depending on the particular SID flown, the radar performance on the day, and the presence of tailwind on approach. So worst case scenario when we have to consult 2 seperate calculations on 2 seperate charts, (x4) decide whether a shortcut can be achieved by changing a SID, re-calculate the revised spacing, by the time it's been decided that it might work, it's too late. It's all very efficient.

bobmij
18th Aug 2006, 20:26
On a slightly different note:
I see that the icao spacings for approach between different types are published in miles eg. 5,4 etc. Are these the same for all airports. I'm sure there is traffic at reduced spacings at Heathrow. ATC sometimes ask for a quick exit from the runway because of this. Can someone explain please.
Ta

Gonzo
18th Aug 2006, 20:38
The arrival vortex spacing varies between countries, and in the UK certainly it varies between airports. In the UK the CAA stipulates that a Light following a Heavy is eight miles. At Heathrow, the same traffic is seven miles apart.

bobmij
18th Aug 2006, 20:40
Two and a half miles seems to ring a bell. Is that between medium following heavy?

Gonzo
18th Aug 2006, 20:48
Medium following heavy is five miles at Heathrow.

If there is no vortex requirement (ie. medium following medium, or heavy following medium, we can use 2.5 miles, if certain criteria are met (10kt headwind, daylight, dry runway etc.)