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-   -   EBOT tolerances question (https://www.pprune.org/atc-issues/571746-ebot-tolerances-question.html)

Miles Magister 11th Dec 2015 12:08

EBOT tolerances question
 
Guys,

I heard it mentioned in conversation that some of the major UK airports now do not allow pilots the +/-15 mins on their FPL departure time, but expect aircraft to taxy exactly on the time. I can not find any reference to this in any documents or procedures. I would be grateful if one of you good guys could direct me to where this may be written.

Also I used to have a doc which listed the CFMU taxy times at major airports for the respective runways but can not find this information any more. Again I would be grateful if one of you could direct me to the reference.

Thank you for your help,

MM

Gonzo 11th Dec 2015 15:45

Airport CDM has muddied the waters somewhat.

Airports with CDM running will provide individual taxi times from individual stand to individual runway, varying by aircraft type, aircraft operator, season and other factors.

So a taxi time from LHR stand 511 to 27R in Summer for a BA 320 may be 14.79 minutes, but in winter might be 13.96 minutes, and for a BA 320 on stand 512 it might be 14.93 mins in Summer and 14.21 mins in Winter.

CDM also uses TOBT - target off blocks time. Airports differ in the tolerance on this time, some insist that you call ready at this time exactly to get push back approval, others have a 3 or 5 minute tolerance.

This should all be detailed in the airport's AIP entry.

Miles Magister 11th Dec 2015 17:21

Thank you. I did search the AIP but was unable to find the information you posted.

wiggy 11th Dec 2015 17:38

Won't do a cut and paste but for example at LHR our documentation, which is derived from the AIP, says something like..


Airport Collaborative Decision Making (CDM)

CDM concept in use at this airport. See GenPart ADR Chapter 6 and in addition:

- Be ready TOBT and inform DLV (time window ±5min)

- Expect information from ATC if delay more than 5min.

- REQ start-up at TOBT +5min, otherwise sequence PSN is lost.

- REQ push-back latest 5min after transferred from DLV.

Hope that's of some help.

DaveReidUK 11th Dec 2015 19:13

Here's what the AIP says:


Airport - Collaborative Decision Making (A-CDM)

(1) TOBT/TSAT

+ (aa) Pilots should take note of the TSAT which they receive from their AO/GH or ATC and comply with it;

+ (bb) If TOBT or TSAT can no longer be met, at any time, then TOBT must be updated by AO/GH;

+ (cc) Pilot should ensure that the flight is ready to depart at TOBT (window of -5 to +5 minutes).

(2) Start Request - Heathrow Delivery

+ (aa) Pilot should report ready to Heathrow Delivery at TOBT (window of -5 to +5 minutes);

+ (bb) ATC will then approve start or in the case of a delay will advise the TSAT;

++ (i) Pilots to monitor the frequency from this point, as TSAT can improve up to TOBT;

++ (ii) Start approval will be issued, based on TSAT and the prevailing traffic situation;

++ (iii) Pilots will be informed of an ATC delay to TSAT in excess of 5 minutes.

+ (cc) If at TOBT + 5 minutes ATC have not received a start up request the aircraft may lose its position in the sequence.

++ (i) ATC will advise the pilot that a new TOBT is required;

++ (ii) Once the new TOBT is entered the flight will be re-sequenced according to a new TOBT, with a subsequent delay;

++ (iii) The aircraft will not be allowed to depart until a valid TOBT is entered and revised TSAT given and complied with.

(3) Pushback Request - Heathrow Ground

+ (aa) Pushback/Start clearance must be requested from Ground no later than 5 minutes after being transferred from Delivery;

+ (bb) If unable to meet this constraint, the aircraft will not be allowed to pushback. A valid TOBT must then be issued by the AO/GH and ATC will then issue a revised TSAT.

(4) Remote Holding Request

+ (aa) If an eligible AO is aware of a CTOT and wishes to take the delay on a taxiway rather than on the stand, then they should contact the Tower Supervisor by telephone to arrange it;

+ (bb) In this instance, the TSAT will be adjusted to allow the aircraft to be transferred to GMC earlier for the remote hold.

confused atco 11th Dec 2015 20:18


the +/-15 mins on their FPL departure time,
This was intended to facilitate ATC.
Problems arise when some operators that its theirs.

Operators should always aim to be at the departure point at their expected take off time.

good egg 11th Dec 2015 20:20

Although at the UK's most punctual airport they still apply +/- 15mins on EOBT :) (Providing flight is not regulated by CTOT)

Miles Magister 12th Dec 2015 21:07

Thank you guys

3miles 19th Jan 2016 17:31

CDM got nothing to do with it - we are talking EOBT here - look in the UK AIP Enroute section which clearly states the requirements, and points out nothing to do with ATC unless ATC are the cause of delay.

It's been regulation for probably 10 years plus that it's the aircraft operator/airline/handling agent (delete depending on your operation structure) to ensure that you EOBT is updated - the issue comes that airlines know they will never make the EOBT(plane not even arrived yet) but don't update it - the crew then call ATC when ready for push and rightfully so nowadays ATC tell them to get their operations(who you paying money to) to update it, issue is for years ATC used to fix it for you - but that can cause all sorts of issues - plus we often now employing someone to do that for you.

Form a network point of view and sector management and production of slots it's the EOBT that generating these restrictions - so in pre planning if from EOBT 10 aircraft are planned to depart and be in a sector at the same time this could result in some form of flow, when in reality 5 of those aircraft won't be departing then they just haven't updated their EOBT - so other aircraft are getting slots based on false data - so airlines that only update their EOBT at last minute generally buggering the system up for everyone else!

Gonzo 20th Jan 2016 05:39

3miles,

You might be talking EOBT here, but it seemed to me that the OP was hearing conversations that were muddling EOBT with CDM-related matters.


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