Departure separation
 

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.

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

Dizzee,

I think this covers it...

In the UK we separate by time.

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

RTFQ Dizzee:ugh:

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

5 minutes ... or else 10 ? Isn't that procedural separation ?
I am asking about departures being radar controlled after departure (radar APP).

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. :)

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

If it would be possible to get just few examples from such speed table I would appreciate it very much.

Mstream

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

Im sure I replied to this yesterday but my response seems to have disappeared?! Hmmmph. :hmm:

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.

We use the tried and tested 'CALENDER' seperation at our airport.1 on monday,1 tuesday etc.Cant get safer than that!!!

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:

Just launch 'em..... Radar can catch!!!!:=

I personally love the:

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

RI

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.

Spacing
 

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