Right-of-Way for traffic being overtaken

[WOHOOO]

Hi, recently one of pilots reported my collegue stating that his FL was changed in spite of the fact that he was the one being overtaken by the succeeding traffic and according to Annex 2 to he has the right-of-way and he must keep his flight level. I checked Annex 2 but under the related section it is stated that the aircraft that has the right-of-way shall maintain its speed and heading. There is no mention of FL. In this respect I am a bit confused. Also in todays traffic flow it is not easy and logical for a controller not to play with the level of preceeding everytime traffic cause there are numerous variants like the settled spacing mimina with the downstream unit by the LoA. In our case the preceeding traffic was an A320 and behind that aircraft at same level there were two A38O's whose performances were much higher than him and going to enter another FIR through the same exit point with an agreed spacing minima of 20 NMs.
Does the right of way cover maintaining of FL and is it mandatory to apply it in any case even if it would be cumbersome and increase the worklod to apply it? Can anyone enlighten me on this issue?

[jmmoric]

When it comes to flightlevels, the first one "shall normally have priority", as stated in DOC 4444.

But look at DOC 4444 5.3.3.6 and 5.3.3.7.

But there are a lot of factors, and every situation is different. So the word here is "normally", it's still at the controllers discretion.

There are a lot of reasons why one would change the flight level of a preeceding, but it usually comes down to, what's easiest.

[WOHOOO]

Thanx for the info. I'll check it.

[ferris]

Does the right of way cover maintaining of FL and is it mandatory to apply it in any case I gather you are talking about the middle east (A380s and 20nm spacing), and we can't run them on parallel headings for long periods? Yes, the priority rules do apply, and they state "first to use the level". However, they also state the controller can change that, if there is "significant economic benefit". So, if 2 A380s can be put in trail at the level of the A320, then the A320 will have it's level changed. What tends to happen during rushes is all the 777's get FL320, all the A330's get FL360, all the dreamliners get FL380, and the odd A320 gets whatever is left (that is an oversimplification). Types with similar Mach numbers can be speed restricted at the same level (eg. A340 ahead of 777 both M82), but numerically inferior A320s tend to "block" the level they are at. Significant economic benefit is therefor achieved by moving the smaller, occasional A320, even if he was at the level first.

[WOHOOO]

However, they also state the controller can change that, if there is "significant economic benefit".

What is the source of this quotation?

[ferris]

They are contained in unit instructions, which go by different names (such as LATSI- local air traffic services instructions, MATS- manual of air traffic services etc.), and are unfortunately not available online, to my knowledge. The 'head of power' for such a rule is ICAO DOC 4444 10.2.1 "Air traffic control units shall issue such air traffic control clearances as are necessary to meet the objectives of collision prevention and the expedition and maintenance of an
orderly flow of air traffic."

[Plazbot]

Like the old chestnut of - aviate navigate communicate ATC have - safe orderly and expeditious. Move the fly in the ointment. Any more questions?

[A Squared]

Hi, recently one of pilots reported my collegue stating that his FL was changed in spite of the fact that he was the one being overtaken by the succeeding traffic and according to Annex 2 to he has the right-of-way and he must keep his flight level. I checked Annex 2 but under the related section it is stated that the aircraft that has the right-of-way shall maintain its speed and heading. There is no mention of FL. In this respect I am a bit confused.

Ok, I think that the root of your confusion is that you're attempting to apply the right of way rules outside of their intended application.

Right of way rules , like in Annex 2, are intended to guide *pilots* as to who has the responsibility to alter course when there is a conflict in the absence of ATC. (presumably, if ATC were present, there would be no conflict) They are not intended as instructions or procedures for Air Traffic Control on how to manage traffic.

As an analogy, think of road traffic right of way rules. In the US, at least, a driver is required to yield to another who is to the right of them in the absence of other traffic control devices That's the key. If there is a stop sign, the driver wit the stop sign yields to the one without, even though he may be to the other's right.

The right of way rules are intended to guide you when there here there is no other information on who has the right of way. They are not intended as rules for programing traffic signals or for traffic cops to direct traffic at an intersection. In fact, as a busy intersection if you had a traffic light that always allowed the driver on the right to proceed, you'd have complete failure, everybody has someone else to their right.

Likewise the Right of way rules for aviation are to keep pilots from running into each other when they have no other guidance, they are not intended as rules for Air Traffic Controllers. There can be many situations where the simplest, most efficient way for ATC to keep traffic moving may be at odds with the right of way rules which would be in effect if there were no ATC present.