French ATC question

[Mister Slot]

I was rather hoping that there may be an ATCO (preferably who works the Brest UIR's) lurking in these hallowed halls to answer a question.

Yesterday I was returning from the Canaries to the UK in a B767 at FL380, approx. 25nm behind another UK airlines' B757 at FL360 on the same routing. Winds and temperatures in the upper levels were pretty consistent, so TAS and ground speed were in the same ball park, as were Mach numbers for both types.

On first contact with Brest I heard the B757 being cleared (without asking) direct to BARLU from PATEL. "Nice one" I thought, because this typically saves 4 or 5 minutes by elimating a substantial dog leg provided by the standard routing.

We made our introductory call and were cleared PATEL POMTA BARLU (essentially the standard "dog leg" routing). Having heard the B757’s advantageous clearance we naturally asked if the same was available, only to be told that this was not possible.

[thinks] "Hmmm, very strange." So we said that changing FL's was not a problem (up or down) if it would facilitate direct BARLU. The reply was a most insistent not possible. We were having a nice day so I sure as hell wasn't going to spoil it by pressing the point and continued on the Canine route.

On examination of the Jeppesen airways charts it was evident that the direct track from just north of PATEL to BARLU passes through one Danger Area and very close (if not JUST) through another. The first has an upper limit of FL275 and the other by NOTAM, to which I could find no reference of activation. So that didn’t provide an obvious answer.

Close scrutiny of TCAS appeared to show arbitrary routings inasmuch that some aircraft (in both directions at various levels) were enjoying direct routings whilst others were not. Lateral spacing did not appear be the causal factor.

Sorry if this is a bit verbose, but I’ve tried to provide as much info. as possible to paint a picture from the pilots’ point of view.

So – why the direct routings vs. stick to the Airway in this case? Thanks for any light that can be shed on this (quite) common brain teaser.

[1261]

You may get an answer to this in the French forum.....

As a UK ATCO, I believe that such routings in France are generally due to the complete segregation of civilian and military ATC.

[AREA52]

Dear MS

In the UK at least, on a Saturday, most danger areas are inactive and we have off-route available for such direct tracks at FL245+. There are a few in the South that remain active, but I believe most of them are low level. However, as said by 1261, the French may operate completely differently.

The other thing is that although as a pilot you may be aware of some of the picture via TCAS or R/T, the controller will have a bigger picture and may be looking further ahead (i.e traffic from other directions/sectors). However, you are unlikely to receive an explanation from the French as to why. I hear that they very rarely accept a/c on headings:eek:

The problem at Swanwick is getting into a sector in the first place, not your route within it.:D

Hope this helps:)

[atccmm]

I may be wrong, but I believe the French have a prediction computer, that shows any conflictions an individual aircraft may have on its route. Could it be that the aircraft in front of you showed no confliction, whereas you did?

Just for the record, you just have to look at the presentiation of aircraft into UK airspace to show it doesn't work.

[XFL]

Hi everyone,

I'm a french air traffic controller at Bordeaux ACC (unfortunately not Brest), so I thought I might help here. And, by the way, this is my first post here:)

Basically, I can see 2 reasons why he gave you the other aircraft a direct BARLU and not you :

1) Brest sectors are fairly huge and maybe he was planning way ahead a sequencing at FL360 over BARLU. The acft ahead of you was n°1, another plane on a different route was n°2 and you were n°3 (or more...). According to the distance he has to put between each plane, he maybe needed to create more distance between you two and he realised that by giving a good direct to the 1st one and not to you...

2) As 1261 mentionned it, there is a complete segragation beween military and civilian control in France (which is kind of scary, but it's not our subject). The TSA (what you call the "danger zones") are activated in real time with a 10 minutes PPR.

So, maybe the zone was activated just after the first plane got his direct (in this case, we try to coordinate with the military the entrance into the zone, we don't want to ask the pilot to go back to the standard routeing just seconds after giving him a direct -- sometimes the military don't accept...) and as a consequence he went direct BARLU and not you...

I don't know if that helps...