Approach sequencing

[RAC/OPS]

This is my first post so please be gentle if you think it's a stupid one!

When sequencing traffic, I'll tell acft what number they are, but when do you think the new sequence starts?

For example, nos 1, 2 and 3 are with the tower, and the next one calls on freq. As he is probably 30 or so miles away, I reckon he is now no.1, as surely it is a pointless exercise to include tower's traffic in your sequence as ADC may have any number in the circuit as well, and I don't always know their plan

So basically what I'm asking, do you consider 'number 1' to be no 1 to land or no 1 in the gaggle that you are working?:O

[This is a crisis]

This is an interesting one!! I always consider no 1 is the number 1 to land. We used to have a SATCO in the olden days who used to say, in the days when you could say it!, 'Cleared to final No1, no4 to land' This used to confuse everyone!!

Where I work you tend only to have one sequence then it all goes quiet for an hour or so !!

[APP Radar]

A new sequence starts when the gap between two consecutive aircrafts in sequence is such that the second will not be affected by the first ... ie if the distance between an aircraft and the previous one is such that the second will not be affected by any delay manouvering of the first or will never spot the previous one then a new sequence should start.

I often advise pilots about their sequence number to have their cooperation on reducing speed or trying to see the previous one (for visual approach)

[brimstone]

RAC/OPS - I've always worked on the premise that No 1 is the next aircraft to land irrespective of where any other aircraft or group of aircraft is. This saves any potential confusion.

Say for example Nos 1, 2 and 3 are all established and working the tower but the next aircraft is 25 miles from touchdown via an 8 to 10 mile final but is passing 10 miles south of the airfield. If you tell him he is No 1 he might say "I've got the field in sight can I take a visual" and suddenly he is No 4.

Rather than get involved in all that, in my opinion it is best not to give a sequence number unless it is meaningful. A range from touchdown when the aircraft is 25 to 30 miles out is far more useful in terms of the pilot's descent planning.

[Jerricho]

I have heard 2 schools of thought on this one, both very similar to the posts of APP Radar and Crisis.

Firstly, an aircraft who is number two in the sequence, but a good 25 miles away from the first, I would quite happily say "You're number two, number one is on short final/x mile final", then you can tell them to keep their speed up if you want or whatever. The drivers can normally take the hint. Another term heard used is "very shortly becoming number one, maintain high speed/specified speed" if required to keep their place in the ensuing "gaggle" (Personally, I use this method)

Conversley, as APP Radar says, you can tell them "You are number one in this sequence", if the preceeding will not effect them if they blatted along as fast as they want.

[saintex2002]

...When on duty on APP, I use to say " number XXXX on IFR Arrival " ...doing so I hope pilots are able to understand : " I'm number XXXX on IFR Arrival but caution with others VFR flights possibly sequenced before me on TWR freq. ... "...and I try to hand over as soon as possible with TWR...

[M609]

A new sequence starts when the gap between two consecutive aircrafts in sequence is such that the second will not be affected by the first

Could not aree more! :)

[HAMMY]

fine until the first a/c in the sequence lands has a problem and blocks the runway,then the other a/c in the sequence is broken off.First question from said a/c is, you told me I was number one!!!

[caba]

I always give the actual number in sequence, including the A/C already with tower. If the gap is big I would add a "no delay".

[604guy]

From a pilots perspective I would assume that being told we are number 1 would mean number 1 to land. We'll often get something like "you are number 1 for runway xx, number 2 for the field. Might also get something like "looks like you are number 11 or 12 for the field".

Being given some sense of the overall picture helps in the whole situational awareness thing. It makes it easier to plan and brief the approach if we have some sense as to how we fit in. We can't always get that from simply listening on the frequency (multiple freq's and sectors could be involved) or seeing a bunch of TCAS targets (may not be going to same airport but a satellite field).

[GearDown&Locked]

Silly question:

When ATC is busy sequencing all the a/c on a rush hour, is it all that important to tell the 4th ot 5th a/c in the sequence its number (assuming this a/c as a visual on the preceeding one), thus increasing the brain-load by trying to find a suitable number for all?

I think it would be easier to inform seq numbers til the 3rd a/c at most , cos the 4th still has plenty to do before reaching final, so its not very worried to know its seq nbr yet.

[Jerricho]

Once again, it can be a personal preference or dependant upon which airfield you're talking about.

Generall I believe a range from touchdown is far more helpful than a sequence number, especially if they are in a downwind position (or vectoring for ILS approaches). It may be well and good that they are number 4, however number 1 may be a heavy on a 4 mile final, number 2 might be a light, requiring a 7 mile wake turbulence gap, the tower may also have asked for a 6 mile gap between no 3 and number 4 cause they have loads of crossers............well, you get the idea. Where as if you give the driver a range, he'll not get twitchy or start wondering why they are being given extended track distance.

[Invictus]

The issuance of track miles to touch down (when not on a STAR) helps the pilot to plan their decent profile if continuous decent is available.

Position in the sequence is not important if the ATC;

1. Does not intend to authorise a Visual Approach,
2. Intends to give track miles to touchdown,
3. Is using speed control.

Position in sequence is important if the ATC;

1. Wants to "hint" at a visual approach
2. Wants to hint that he is buys and would like minimum woffle on the freq.
3. Just wants everyone to know how busy he is.

On a side note, I know an ATC whose favourite reply to a "what is our position in the sequence?" is

" ABC123, I have you pencilled in at number 2, but I do have vacancies at number's 5 and 7!"


Invictus

[FWA NATCA]

When I worked at a VFR tower the radar facility would tell IFR inbounds that they were number 1, when the pilot switched over to the tower I would inform them that they were number 3, 4, etc. The pilot would become confused, or angry because they were origionally told they were number 1 and now they aren't.

As a Radar Controller the only time that I tell an inbound what number they are is only when the pilot reports the airport in sight and expects to be cleared for the approach, but isn't because of sequencing.

Often I tell the pilot that they are being vectored for sequencing (which they should realize because they hear me sequencing and clearing other aircraft), if the pilot ask what number they are I'll tell them.

Mike
NATCA FWA

[ILS 119.5]

The landing sequence is not important. DFT is, because it does affect the descent profile. If I'm no. 8 to land at EGLL then I have about 24 miles to touchdown. If I'm no.8 at a single runway airfield then I may be 60 miles from touchdown. Big difference.
I know ATCO's have to say what your number is in traffic, but to me it is a waste of time.

[Canoehead]

I believe that when a pilot asks "what number are we", he really means "how far will I turn final?". So I usually answer; "expect a (15) mile final. Exception is when he is really No. 1, in which case he'll get a normal vectored approach, or a visual if the wx's good.

[Goldfish Jack]

Why bother to even tell the aircraft his number in the sequence? Is it of any consequence to anyone? In any case, having told an aircraft his number, is it updated at the preceeding a/c are handed over to tower??

IN the centre where I work, often if there are more than 2 a/c they are taken off the STAR, for some unknown reason, vectored around an empty TMA and then they have no clue who will be number 1 or 2 or 3!!!!!!!!!!!!!

Surely logic says give the a/c his distance from touchdown, if it is not published on the STAR plate, and then tell them when they arenumber 1 for the approach.

Hell, I am sure pilots could not care what their number is, until they are number 1.

"please hold you are number 245 in the queue and your call will be answered in 2 days. Please be patient and enter the hold"

[av8boy]

There are times when it’s simply beneficial to me and to the customers to provide a sequence number. What comes to mind right away is something like telling a pilot on the downwind “…number three following a Citation on a six mile final…” With that call I’ve let the pilot know that he’s looking for the second of two aircraft on the final. He’s looking for that traffic, knows what my plan is, and has become a partner in that plan. In my perfect little world, he either sees the traffic and tells me he’ll be following it, or happily waits for me to turn him at exactly the right moment, having prepared for that moment because he knew my plan.

Of course, in my less-than-perfect world he always says, “can we get a short approach?”

Dave :)

[604guy]

Heaven forbid....you mean us pilots being partners in the plan?! That way we might do something silly like be in a better position to plan ourselves and keep the folks in the back informed.

Actually thank you Av8. I couldn't resist the comment though. It must have been the bottle of grape squeezin's......honest...really...no I don't want a holding clearance thank you......................;)