Conditional Line Up Clearances at LHR

[Human Factor]

I've just re-read the AAIB report on the BA/BM incident of April 2000, it mentions that at the time, Heathrow ATC were considering implementing a restriction on the number of conditional line up clearances. Having been given a couple of excessive clearances (as I see it) in the past few months, (for example: "line up 09R behind the BM 737 on the northside", where having counted, the BM 737 is ninth in the queue), I would be interested to know what the restriction actually is, and does it differ when single and dual landing runways are in use?

Not necessarily a criticism, just a query.

[HEATHROW DIRECTOR]

"line up 09R behind the BM 737 on the northside"

For a start, no ATCO would EVER say that in that order, but pilots say it over and over and over... I wonder why???

[Human Factor]

OK, that may be me :eek: (and a few others) - will keep that in mind - anyway, what about the question?

[ATCO Two]

There is a recommendation that we should have no more than six aircraft on conditional clearances, however if there is no chance whatsover of any misunderstanding, I don't see any reason why there couldn't be one or two more. The danger of lining too many up is that when an aircraft arrives at the holding point with a tight CTOT, then it can be potentially more difficult to revise the departure order. I usually indicate their projected number in the sequence to aircraft when it is busy. The number of aircraft with conditional clearances is largely academic; having identified the traffic they are following, pilots only have to remember one aircraft and then line up behind it. If there is any uncertainty then they only have to request confirmation of the order. If there are several aircraft of the same company/type then the controller will identify the aircraft to be followed more precisely.

If HF was able to successfully identify the aircraft he was following (as he obviously was), then I suggest there was not an issue.

During single runway operations with one aircraft to depart in the gap, we will only issue conditional line up instructions subject to one aircraft. In LVPs, aircraft will be given individual line up clearances.

In mixed mode it depends entirely on the size of the gaps between the inbound aircraft. Working on a rough 3 nm per minute time separation, controllers can calculate how many aircraft will be able to depart safely in the gap.

The departure sequence is all about safety and expedition; if Heathrow controllers lost the ability to use conditional clearances then capacity would doubtless suffer.

Lastly on the subject of RTF phraseology HD makes a good point. If pilots were to read back the clearance exactly as passed, then controllers would be a lot happier!! In the example quoted it would be, "After (not behind), the departing BM B737 on the North side of the runway, line up and wait 09R". The condition comes first, the description second and the instruction last.

My biggest bugbear is with pilots' readback of runway crossing clearances. PLEASE read them back in the format passed as above. NOT, "Cross 09R after the departing/landing (company/type)"!!!!! Easy isn't it?

[Human Factor]

Thanks ATCO Two. Will endeavour to get the RT right in future.

HF

[GoneWest]

For the pilots that simply haven't thought of it....if you respond with the clearance first - and then follow it with the attached condition - but for some reason the end of your message is blocked or not received.......all that the controller may have heard is "line up" or "cross runway **".....and that can lead to heart failure.

Any other reasons, ATCO Two?

[ATCO Two]

Got it in one, Gone West!

There is a NATS project at the moment which is examining standards of pilot RTF phraseology. To my knowledge pilots do not routinely undergo any continuation training or examinations in RTF after their initial test. The results of the NATS project will be illuminating.

[Scott Voigt]

Shoot, I wish that we even had a test for pilots for phraseology. They seem to just make it up as they go along here. Just trying to get folks to use a call sign all the time is getting to be really rough...

regards

[GoneWest]

Scott - a sequence of thoughts from your posting....I was at a seminar hosted by an "Orlando International" tower/approach controller.

He was growling about too much readback stuff from pilots and said that the best response to an IFR departure clearance, such as...

"Mouse 757, cleared to London via ABC, DEF, (airway) 1, 2 and 3 to GHI, after departure maintain two thousand feet, expect flight level one eight zero in ten minutes, departure frequency 123.45, squawk 1234"

would be.....

"Roger"

Is this correct? (I have this seminar on video tape).

[tired]

Gone West - yup, that's about it. All they want over there is for us to read back the squawk, nothing else required unless we have a question.

ATCO Two (or anyone else in LHR Twr) - please excuse what will seem to you a very dumb question ( but then, I'm only a dumb pilot :) ), but why exactly would losing the ability to give conditional clearances at LHR impinge on capacity? Actually, let me rephrase that - why do you sometimes give 5 or 6 aircraft conditional clearances? I can see the advantage of giving the one at the head of the queue and the one behind him a conditional clearance, but how on earth does it help to have zillions of us all conditionally cleared?

And do remember I'm only a dumb pilot, so please be gentle with me!! :)

[ATCO Two]

Tired,

Let me rephrase YOUR question, why NOT give 5 or 6 aircraft conditional line up clearances? If the runway is only being used for departures, and there is no ambiguity and no chance of misunderstandings, the procedure is safe and efficient. Workload is reduced if you can give a series of line up instructions sequentially.

Air Departures is all about priorities - using the available RTF time effectively. You need to time your instructions carefully so that no time is unnecessarily wasted. You cannot afford to be issuing marshalling instructions when you should be issuing take off clearances. Those lost seconds mount up over the course of a day and become significant, and lost time as we all know is money and lost capacity. If a pilot knows where he is in the sequence, then he can plan to have his checks complete, line up on the runway promptly, and roll immediately on receipt of take off clearance. We get minimum departure spacing, you get minimum delay.

[Gonzo]

And of course there's the fact that if you've got 10 at the hold, and only three given line up clearances, all the others start asking "where are we in the sequence??". The R/T time spent answering these queries could be better spent actually giving a line up clearance.

Gonzo.

[M.Mouse]

Gonewest, how did you know I fly 757s?

On a serious note, I agree that the standard of phraseology by UK pilots appears to be slipping. How many times does one still hear affirmative for example, a word changed for good reason in the mid - eighties?

If the standards are becoming a cause for concern I would suggest that NATS concern is brought to the attention of the airlines. In my own airline we have numerous channels of communication that are used to address a problem. R/T is sometimes, perhaps not enough, de-briefed after our annual route checks.

It is my observation that we (UK) are actually very pedantic when compared to the USA.

That is not a criticism of either country but, as has been mentioned, in the US the readback of the squawk signifies that you have understood the clearance (which can be very long and involved). If the clearance is not read back in full then how can the controller judge whether it is understood or not?

Taxi instructions are often acknowledged with 'Roger'.

Having said that if one did read everything back in full in the US many airfields would grind to a halt. LHR is busy but try LAX or ORD on a busy day.

[tired]

ATCO Two - yeah, fair enough, there's no reason not to, it just seems an awfully arse-about-face way of doing things. I often seem to roll up to the holding point, hear a frantic burst of activity on the RT as half a dozen conditionals are given, then minutes of utter silence broken only by the occasional T/O clearance. And then of course every once in a while the whole thing has to be rearranged when some aeroplane with a tight slot suddenly appears! (And don't we just love it when it's a Virgin :) :) ) Still, if that's what blows your hair back, far be it from me to carp about it!

One point I should make is that I, and every other professional pilot I've ever flown with, always approaches the hold expecting an immediate T/O clearance - in other words, we make sure all the checks (except the "below the line" checks which should only be done as we enter the runway) are complete and the cabin is secure so that if we do get an immediate we're ready for it. In the instances when we're not going to be ready on reaching the hold(and there seems a chance that we might be cleared immediate) then we'll tell you we're not going to be ready - it's only proffessional. There again, maybe I've just had a sheltered upbringing. :)

[Muppit]

Tierd,

Just because we're not talking on the r/t doesn't mean we're not working.;)

As ATCO 2 says, runway management is all about priorities: We can be on the phone coordinating with radar, talking to GMC, looking for a Virgin with a tight slot, :p trying to get Flow to release someone early....and on and on. So that frantic burst of activity gives us the opportunity to get on with other tasks in the knowledge that the runway/departure order is sorted for the next 5/10 mins.

[HEATHROW DIRECTOR]

Muppit makes an excellent point, which many pilots simply don't understand. There are times when we hardly have time to talk on the R/T, there's so much else going on "off-air".

[Scott Voigt]

Gone west;

All we really need for you to do is read back the transponder code. However, most of the busy places, the reason that you do that, is that we have something called PDC ( Predeparture Clearance.) You get your clearance either from a printer at the gate or on your ACARS. You just read back the code to ensure that you got the right flight plan clearance.

As controllers, we normally like short read backs. If you read back a clearance, <shrug> ok, hopefully doing that because you haven't gotten one via PDC. If you are in doubt, they you should always read back everything. However, if you are sure that you got it right, then let your feelings be your guide... Wilco or your call sign is a very nice read back. It puts all the onus on the pilot <G>...

Speaking of Seminars <G>, we have a safety seminar coming up in April for you to come too in Denver <G>...

regards

[vector4fun]

Scott,

Is somebody at some of the seminars preaching read back the squawk code of a PDC clearance? None of the regular airline customers do, and I wish they wouldn't. Call me if you have a question or you didn't get it, but I'll assume you did otherwise. Lately though, I've had some 91 and 135 operators call me at CD with the squawk readback from their PDC. I was wondering where they got that?

(me-- "Yeah, so what?")

DT @ AUS

[ATC Sweden]

In Sweden we also have this PDC system at some airports. Don't know if it's the same as in the US, but in the swedish system, pilots never speak to clearence delivery. They get the clearence via ACARS and then just press the button to accept it. Next call they make is to ground.

About readbacks... very surprised about this "roger"-thing. The situation in Sweden can be good described by examples like these:
GND: Spainair 123, go behind the Scandinavian 737 at your ten o'clock.
JKK123: Roger, JKK123.
GND: JKK123, readback please.
....
CD: SAS123, Cleared ***** via AB, ABCDE, UN456, FL80 bla bla bla.
SAS123: Cleared ***** via AB, ABCDE, FL80 bla bla bla. (the same but not the airway)
CD: SAS123, negative, after ABCDE, cleared UN456.
SAS123: After ABCDE, cleared UN456.
CD: SAS123, readback correct.
....

So I'm having kind of hard to understand how you can readback a long and important clearence with just roger and still think it's safe (if it's not given as PDC or similar way)... :confused:

And last about the after/behind conditional clearences... I've learnt it's supposed to be...
"Behind DC9 on short final, line up runway 26 behind." :p

[Scott Voigt]

DT;

The code was at some of the large places a few years back. I haven't watched them lately to see if they have changed or not. The code readback was to determine if they both had the right flight plan...

regards

[GoneWest]

Scott & Co...

The "Roger" only readback that I mentioned was explained to a group pf private pilots - some IFR, some VFR - and wasexpressed as a suitable readback to a verbally issued airways clearance for a "general aviation" flight. No ACARS there.

[LateLandingClearance]

I remember when NATS put effort into developing useful things like PDCS. It was in place at LGW for trials which worked, it seemed, really well. The kit is still there, just seems like no pilots want to use it any more :( Maybe they've all been told it's not working any more :confused:

Ah well.........

[West Coast]

When I recieve a clearance I don't intentionally record it incorrectly. I repeat it back fully expecting to be told "read back correct" Unfortunately from time to time I am corrected on something. Point being that even routine clearances can be hacked up. I suggest pilots always read back the clearance. I also recognize that controllers may not catch errors in the readback, but then again they might. I also recognize there is a finite number of clearances that can be read in a given period of time. That number of course would increase with a "roger" in lieu of a full readback. I have waited 10 minutes plus at LAX awaiting a clearance. That is the price for the additional level of safety a readback provides. Those mistakes will start to be caught by departure or center guys as we blow through an altitude that might have been caught by the CD controller