start-ups prior to EOBT

[Cecco]

I'm in business aviation and fly within Europe and of course, sometimes our passengers turn up early and luckily ATC approves an early start-up (unless a slot applies of course), even if it is 30-40 minutes prior to the EOBT. I found the information that if start-up is requested prior to the EOBT mentioned in the flight plan, a new flight plan would have to be filed. However, until now, we never had to do that. I'm somehow surprised about that. How much flexibility is there for earlier than expected departures, are there any "unofficial" rules? Also, I read that a new flight plan has to be filed if the EOBT is exceeded by more than 11 minutes (if the FPL is subject to ATFM, which I suppose most flights are) or a "delay message" could be sent. How come ATC is flexible with early start-ups but not with late start-ups? Furthermore, I have never encountered the use of the "delay message" in real life so far. Is that still applied (my information source is my flight planning ATP folder dated 2002)?

[Stpaul]

All yours answers are in CAA CAP694 chapter 6 i think.

[Cecco]

It took some reading but I got my answers, thanks Stpaul!

[eyeinthesky]

In an unregulated (= no slot) environment, a Tower's 'flexibility' may be storing up problems for sectors hundreds of miles away.

En-route capacity is finite, and the decision whether to regulate is based upon flight plan and radar data. If the flight plans do not indicate an excessive demand for a certain period (say 30 mins, but more often in the UK 15 mins) at a certain 'choke point', then no regulation will be applied.

Now let's assume you call for start 30-40 mins early and your local tower approves it, as there is no slot restriction. You get airborne, and arrive at the 'choke point' 30-40 mins earlier than filed. Now add several other airfields who have done the same (or let traffic depart 30-40 mins after EOBT) and you can see how a bunch of traffic can build up. Bunching of unregulated traffic is one of the biggest causes of overloads in ATC, and it is a serious safety risk.

If you are ready 40 mins early, you should re-file without relying upon the tower's flexibility. The rules which say you should for taxi no more than 15 mins before and no later than 15 mins after EOBT are there for a good reason. Please help by complying with them.

[GuruCube]

'eyeinthesky' is exactly correct. :cool:

[MANAGP]

Cecco

Now I understand why when I adhere to the rules I still don't get the filed level or route!

Is this practice commonplace in Business Aviation?

Please adhere to the rules!