ATC IssuesA place where pilots may enter the 'lions den' that is Air Traffic Control in complete safety and find out the answers to all those obscure topics which you always wanted to know the answer to but were afraid to ask.
Is it really true that when you put a REA msg into the system, the MINLINEUP is only taken into account from the time the msg is put in? I.e. once the minlineup time has expired you could get a slot that's in 4 minutes time on minlineup of 20 mins (as happened yesterday) which is Dafty McDaft when the a/c is waiting on stand for any improvement and taxi time is 20 mins! (Got him airbourne within the slot though. )
If this is the case, can anyone explain why it is so?
A Slot Revision Message may be sent in response to an REA message with a minimum inprovement of 5' The MINLINEUP is the minimum time needed for that flight to get from its present position to airborne. 5' is the absolute minimum, 45' is the maximum. If no MINLINEUP is specified then the taxi time valid for that aerodrome will be used (that can be up to 45').
To answer the original question the minimum line up time is not counted from the time the message is received, but considered when the new slot is calculated, e.g clock time 1000, MINLINEUP 10' earliest slot allocated will be 1010.
The slot normally takes a few seconds to appear on your printer, it's almost instantaneous. There have been occasions however when Comm centre problems for AFTN or SITA mean messages can be significantly delayed. Hopefully introduction of the CFMU internet application should end that particular problem.
I have not seen any info on the "CFMU Internet application" - would be interested to know where I can find the latest gen on this. Also, is it meant to directly replace the AFTN-linked Departure Slot Monitors we currently use to request REA/DLA msgs?
Connex There are two levels of internet access. One is public and contains information on the ANM, AIMs NOTAMs and so on. The other is a protected and to subscribe go to http://www.cfmu.eurocontrol.int/serviceagree/index.html I think it costs 100Euros for a pin but that's it.
Point 5 is correct in what he says if related to a normal Slot Revision Message (SRM). But if you send an REA with a MINLINEUP of 5' then all that TIS + Taxi stuff goes out of the window. If you tell us you can get the aircraft on the runway in 5' then thats what we use to calculate the slot.
Gonzo: If you are sending REA messages without a minlineup then your Slot revision will be based on your taxi time. If thats 10' then of course you will receive a slot only 10' in the future. If you ARE including a minlineup then we will use that figure.
LHR does not have a MINLINEUP. If it does, then I've not heard of it. Our taxi time is 16 minutes, apart from one runway where it's twenty minutes.
Scenario: XYZ123 calls at 1000 for a 1005 slot. He's not going to make it. We use the DSM to get a new slot via a DLY msg (entering in the new EOBT time of, 1005, which based on a taxi time of 16 minutes should get a slot no earlier than 1005 + 16 = 1021). The new slot is 1100. We send a REA msg. At 1015, a new slot comes through with 1025, which is not going to work if it's anything other than very quiet.
This happens so so often. Many of us now don't bother sending REAs if the slot is within 40 minutes, because we fear the improved slot will come through which leaves the a/c no chance of making it.
There is no default MINLINEUP anywhere. It is what you, as the tower controller responsible, say it is. If it takes 20 minutes to get someone to the runway then specify that as your MINLINEUP. If you have somebody remote holding then it may be a shorter time period, just specify that in the message. If you can't get them to the rwy in 25' then don't bother sending an REA message. Don't forget, all flights are in RFI status (ready for improvement) by default anyway. So we know they are waiting for better slots unless they tell us otherwise. An REA message is just a means whereby ATC can tell us that a particular flight can be airborne within a specified time period.
The examples you give are unlikely to be because of AFTN problems. The only way to analyse such things is with actual incidents on the day. Next time it happens send me a personal message and I will investigate (if I'm at work) and let you know what happened.
We also get new slots by using DLA msgs, (oh for the days of SRR...) but on the REA msgs the default MINLINEUP is 0020 (taxi time). We'll change this depending on traffic situation and a/c position. Surely you must be able to input a MINLINEUP at LL?? However, like LL we also get slots coming forward to a time less than whatever MINLINEUP was specified and I can't believe they're all down to slow AFTN links.
Also, on the point on min MINLINEUP, we will often put it down as 0001 if an a/c has got to the hold early and it does work sometimes.
I've just seen the reply above and will take you up on it flowman if it happens again soon at KK too. Thanks.
Please do I.N.J.Sir. You are right that this cannot all be down to slow AFTN links. The other possibility is down to human intervention. Many slots are improved manually by controllers at FMD. If an empty slot becomes available it is often REA flights that are forced into them manually. The correct procedure is to check in the list of messages for the flight concerned and to look at the actual REA message to check for a MINLINEUP parameter. Often by the time that has been done the machine has given the slot to somebody else, so it's very tempting to just allocate the new slot immediately and check afterwards. Send me some examples as discussed above, and depending on what the outcome is we can always tighten up or change our procedures.
Lon More Thank you for your concern over our job title Its a contentious issue. Management describe us as controllers when it comes to our pay grades and flow managers when discussing ESARR 5 licensing and competency issues. This is also reflected in official documents. So I'm not sure what we should call ourselves. I know you all have your own names for us though
"Related question During the past year we now receive with our Eurocontrol invoices additional charges from individual countries for ATC services.
Can someone explain these additional charges?"
You asked the above question about route charges (which seems to have disappeared from this thread). I apologise for the delay in answering your, but I had to find the right person to give me the answer which is as follows:
CRCO sends three types of bill for ATC services - 1. the "multilateral" bill for en-route charges in the Eurocontrol Charge Area 2. approach charge bills for member countries which have requested us to make this billing on their behalf (eg Ireland, Denmark, Italy...) 3. bills for air navigation services for countries which are not member states of Eurocontrol but which have requested us to make this billing on their behalf (eg Belarus, Uzbekistan, Morocco...)
You indicated in your question that these additional charges have appeared "during the last year" - the above arrangements have been in place for several years now and my source in CRCO was not aware of any changes which have occurred recently.
Hope this answers your question, if not you can check for further details under CRCO in the Eurocontrol public web site.