Filing Low IFR Altitudes

There was a recent thread on low IFR filing in France. I can’t search well right now…

In principle, there is no difference between the lower and higher altitudes in the Eurocontrol airway system, but there are fewer legal routes at lower levels, or they are harder to find.

The reasons are

• high MEAs en-route – while controlled airspace (including Class E) may go down to quite low, the route MEAs can be higher in practice, although the 5-8000ft range is not that much affected by this. For example – Germany has Class E down from 2,500 AGL upwards (1,000 or 1,700 in TMAs), but MEAs can be quite a bit higher, making a band between 2,500 and around 5,000ft difficult to route in (altouhgh in practice they can then clear you down to the MRVA). The UK is especiialy famous for this, because the MEAs for airways outside TMAs and CTAs are very high to free up airspace below the route for everybody (which is good) but there is a completely different ATC environment below the route and you have to renegotiate your return into CAS if you leave it (which is less good)
• high MEAs in TMAs – TMAs have minimum overflight heights, ranging from FL80 – FL120+, so airways leading through them might have an MEA to reflect that
• alternatively, some low-level routes are only available for specific destinations. So while the chart might show you options, in practice they are not available.

But all this is only theory these days. You plug in your desired route into any of the available routing tools, together with the altitude you want to fly, and see if it finds one.

I only have experience from filing low altitudes in Sweden and that is generally very simple. There are no airways to file so you just route Waypoint1 DCT Waypoint2 DCT and so on which can give you very direct routings.

The thread I referred to is here.

The really key point to appreciate in all this is not whether one “can” file a valid flight plan at a low level (say a few k feet). You can do it in probably most countries in Europe, in terms of Eurocontrol validation.

The first issue is whether you will get any “rights of way” – in Eurocontrol IFR you get a seamless flight, with no CAS clearances needed because they are already implicit (your departure clearance did after all contain the phrase “cleared to xxxx destination”). When the Autorouter first came out, I got a really angry email from an old pilot friend (who had an CPL/IR but like almost every other product of the FTO system he didn’t have a clue about how to actually fly from A to B) who filed a flight plan across the UK at something like 4500ft. He then got into a C172 and flew it…………. The resulting mayhem with ATC made him wish he should never fly a plane again. What he discovered is that many countries don’t supply Eurocontrol with all the restrictions. Many do it deliberately for job protection reasons (Germany is one of these, according to one German pilot who knows the system there). So in (in this case) the UK you can file for some low level but the result is completely worthless. On top of that, London Control will dump it as soon as they see it, so nobody enroute will have a copy… One could make an academic argument that the guy’s flight plan was indeed valid… being completely worthless is no grounds for rejecting it

The next issue is whether your low level flight can be escalated in altitude to get above hazardous wx. That is after all why we got the IR. It isn’t so we can sit in the muck. In the UK this (what in the USA is called a “popup clearance”) is basically impossible. The London Control controlled airspace is watertight; they won’t let you pop up into it. And if you declared a mayday, that would work but the resulting “interaction with the CAA” would make you not want to do this again… or indeed fly a plane again, perhaps. I actually suspect that in some of the countries whose pilots proudly say you can Eurocontrol-file at 3000ft etc, you cannot just climb up to FL200 to get above wx, and/or get that climb quickly. In France you can get it, in theory, but it can take 10-20 mins to convert a low level flight (basically VFR) to high level IFR. And you may never get it, especially if there is some military activity (the military basically own the air in France) affecting what you are asking for.

And so on… so much depends on the detail of what is possible and how you can get it.

Peter wrote:

I actually suspect that in some of the countries whose pilots proudly say you can Eurocontrol-file at 3000ft etc, you cannot just climb up to FL200 to get above wx, and/or get that climb quickly.

In Sweden you can. Definitely. The reason being that the FIS you talk to at 3000 ft in class G is the same guy (on the same frequency) who is ATC for the control area above. And (s)he has your flight plan — no doubt about it.

(Above FL195, there will be another sector so some coordination will be needed — but that is no different from being on controlled airspace below FL195 from the beginning. And there may of course always be conflicting traffic.)

Well Denmark’s ATC is almost identical to Sweden’s, so it should be no surprise that i can attest to Airborne_Again’s statement. It is the same in Denmark. Not an issue.