EOBT inconsistency

[michael ATC]

Hi everyone
It is becoming a pressing problem
I mean EOBT issue at my unit
As I understand it's time when pilot
is allowed to start move from the stand but
some pilots prove that they could taxi 10 even
30 min before this time and 30 min late, so it
creates a lot of cluters.
How do things work at our units boys any info please

Regard M.

[HEATHROW DIRECTOR]

Simple - do not issue start-up clearance! Start-up times should be issued to ensure that there is a steady flow of traffic, with minimum delay at the runway.

[michael ATC]

Great idea
but saying simple shut up and wait
sounds not so good
Do you know any referenses where I can get any
details, just to explain them that they are wrong.

[reportyourlevel]

Assuming you're in the Ukraine (as your profile says), then you are in the IFPS zone and the Eurocontrol CFMU handbook is the document you require. You can find it on the web here.

Section 3 page 3-3 says that any change of more than 15 minutes to the EOBT shall be communicated to the IFPS. In the case of being ready after the EOBT, this can be via a DLA message, but if the aircraft is ready early they can either wait or cancel and then refile for an earlier time (negative delays are not accepted).

[HEATHROW DIRECTOR]

<<Great idea
but saying simple shut up and wait>>

Hmmmm... don't think I ever said that to a pilot! When a pilot calls for start up, tell him when to start. It's a simple procedure which is employed at just about every major airport in the world.

[Sand Devil]

Great idea
but saying simple shut up and wait

Or even "C/S Standby for start, I will call you"

[michael ATC]

Many thanks to averybody
I have to apologize for my for my rudeness
I mean sh...
It was couple days ago. Pilot requested start up
18 min before I said stand by cause EOBT
He insisted and declaried He could depart 30 before
and 30 min late
We have the situation like this one off and on,
but it was the last straw I thought I probably
have a huge gap in a knowlege concerning CFMU.
So I decided to apply to such remarkable community
for advise
Once again thanks a lot.
Any additional info would be deeply appreciated

Regard M.

[chevvron]

In the UK, if a CTOT has been issued by IFPS, departure has to be from 5 min before the CTOT to 10 min after. If no CTOT has been issued, then it must be between 15 min before to 15 min after the filed FPL departure time. Details are in the UK AIP.

[windowjob]

Sorry HD it's got far more restrictive nowadays. The stupidest part is that a pilot can delay his plan, but if he's ready early can't bring it forward. He has to cancel and then re-file a completely new plan with the earlier time.
Computers - pah!

[michael ATC]

How much does it take to re-file FPL
Could pilot do it on his own or
He has to apply to TWR.

[13370khz]

windowjob

If ready between filed EOBT and that EOBT -30 tower or FMP
MAY send ready msg ?

[Antek]

Ready message only applies if the a/c has a CTOT.

The formula we should use (in the European area) for departures with no CTOT is:

Earliest airborne time = (EOBT - 15 + taxy time) to EOBT + 15 + taxy time.

Declared taxy times vary depending on airport, time of day and wx conditions.

At my airport, for example, this means airborne between EOBT - 5 until EOBT + 25 for a departure without a CTOT. So start-up clearances are timed to allow for this, and current traffic conditions.

It can be frustrating for all, but hey - rules are rules. They do, actually, have a reason (so I'm told). Personally, I blame Brussels...

[bookworm]

The formula we should use (in the European area) for departures with no CTOT is:

Earliest airborne time = (EOBT - 15 + taxy time) to EOBT + 15 + taxy time.
...
At my airport, for example, this means airborne between EOBT - 5 until EOBT + 25 for a departure without a CTOT. So start-up clearances are timed to allow for this, and current traffic conditions.

Your formula and policy is perfectly logical, but unnecessary. While a CTOT applies to airborne time, and requires the cooperation of ATC to get the aircraft in the air in the correct CTOT-5 to CTOT+10 window, the -15/+15 restriction on EOBT is exactly that, and it's permissible to get off blocks at EOBT-15 and taxi quickly, or at EOBT+15 and taxi slowly.

I get the impression that the latter is much less critical to the smooth running of the system than adherence to slot times (which tends to be no better than 90% anyway). Nevertheless, the law requires ATC to ensure that "(c) flights not adhering to their estimated off blocks time, taking into account the established time tolerance, are not given take-off clearance;"

I think this causes unnecessary grief. As reportyourlevel indicates, while a DLA is easy, bring forward an EOBT is complex, requiring a cancellation and refiling of the FPL. Among some operators, this leads to a systematic error in estimating EOBT, as it's easier to file early and delay than the reverse.