ATC special procedures @ LEVC ??

[saleya22R]

Hi everybody

I don't know if my question is for an ATC or pilots, but I'm trying to understand some special request from the ATC during a flight departing from LEVC.

Here is the story:
I was flying IFR (light jet) from LEVC to France. EOBT of the FPL was at 14H00.
We asked start up around 14H05, and still waiting for the PAX, we only requested taxi around 14H15. ATC cleared us to taxi, and asked us if we would be able to be airborne before 14H25 (!!??).
And that's my problem, i don't understand why there is a restriction on the take off time since we didn't have any slot.

I know that, before taxiing, after 14H30 the FPL is suspended. But once you taxi, your FPL cannot be suspended.

Anybody has this type of experience before ?

Thanks ;)

[jpc]

Assuming that LEVC's taxi time is 10 minutes, I think I might have a good idea of what happened :8

It boils down to this:

1. Your flight didn't receive a slot because according to your EOBT, routing, altitude and speed, it was not necessary to issue one.

2. When you don't have a slot (or CTOT) you have a ETOT (estimated take off time) to comply with: ETOT = EOBT + 15 minutes tolerance + airport Taxi Time.

3. So, in your case ETOT = 1400 + 15min + 10 min Taxi time = 1425.

You can have a look at Eurocontrol's ATCFM manual on this link, it actually has a lot of useful information:
http://www.cfmu.eurocontrol.int/cfmu/gallery/content/public/library/handbook_supplements/basic_handbook/docu_atfcm_users_manual_latest.pdf

Of course, if LEVC's taxi time is something other than 10 minutes... then I have no idea of what went down :}

By the way, your FPL is suspended only after 30 minutes after EOBT + TAXI TIME! And it will be suspended while you taxi, while you line up and even on the departure roll!

[Lssar]

Hello saleya22R

I work as an ATC in a collateral ACC to LEVC. We have had in the last week military exercises afecting part of Sevilla and Barcelona FIR´s, over San Javier airbase. As we try not to penalize the traffic (even if some of you up ther don´t believe it ...), coordinations can be made with our colleagues in blue uniform to try to use active areas during low activity. This could explain the time constraint that the ATC from Valencia mentioned to you. I myself saved more than 20 min. of flight to an Air Berlin from the south of Spain to LEPA, which initially had the FPL through Argelia, due to the military exercises.

This is only my 2 cents, but it could be some other reason.

Saludos!

[saleya22R]

Hello Lssar

First thanks for trying to explain !
My flight was a sunday afternoon in december (the 18th).

I was surprised when i tried to discuss with the ATC on the frequency, he told me that the FPL validity is 25min, i tried to told him that normal FPL is valid 30minutes and he disagreed (!!!).
I tried to find in the Jeppesen doc if there were special procedures in spain for FPL but i didn't find anything.
In the Eurocontrol doc, it is also said that the FPL is suspended after 30 minutes...

Still very strange...

[BOAC]

Still very strange... ? Is this not explained beautifully by jpc in post #2?

[saleya22R]

Sorry jpc, i saw the message of Lssar before yours

Thanks for your answer, it appears to be obvious now.

But concerning the FPL suspension, an other ATC told me that after you start to taxi the FPL cannot be suspended...
Do you have a reference concerning FPL suspension ? I didn't find anything in the ATFCM user manual

Thanks

[Andy Mayes]

But concerning the FPL suspension, an other ATC told me that after you start to taxi the FPL cannot be suspended...

This is inaccurate. It does happen although most pilots tend to say it can't, several times I've had to tell a pilot as he taxi's out is has and when those 4 crosses appear on the ATSA data screen there's not a lot I can do about!