Cobalt wrote:
here is nothing preventing a procedural IFR clearance in Class E below the MRVA, but the DFS does give any IFR clearances below the MRVA, which creates a “no mans land” band of Class E airspace that cannot legally be used in IMC.
Actually there is. According to PANS-ATM, ATC is responsible for terrain separation unless the aircraft is following an established route — i.e. when cleared direct or radar vectored — so they can’t give a clearance that will take the aircraft below the MRVA (or the MSA of an approach) unless the aircraft is on an established route.
IFR in class G is fully accepted and supported by ATS in Sweden, but you still can’t get a clearance to descend out of controlled airspace if the MRVA (or MSA) is above the base of controlled airspace unless you are following an established route. (Approach procedures count as “established routes”.) Leaving controlled airspace laterally is of course always ok.
In addition to the terrain clearance challenge there is a second (and from a German to the letter point of interpretation even more difficult) challenge: vertical separation!
And this one ios not even connected to MRVA.
In controlled airspace ATC is responsible for IFR/IFR separation. Minimum vertical separation requirement is 1000ft to any other IFR-traffic independent from which airspace this IFR traffic is flying in. Therefore if uncontrolled IFR traffic can legally fly up until the upper limit of airspace G, ATC can have no IFR traffic fly in the lower 1000ft of the airspace E above it because they can‘t gurantee seperation. ATC doesn‘t like to be responsible for something (esp. seperation) which they can‘t control.
Therefore the German solution is to not have any IFR traffic in these 1000ft. And exactly for that reason there is a „1000ft gap“ between the airspace G you could fly IFR in and the part of the airpace E where ATC would let you fly IFR. This problem technically is real – and ATC in a country can only decide between not to care for seperation in this piece of airspace or doing what the Germans do and not let someone pass through this „1000ft gap“ under IFR.
The only correct systematic solution would be to have a new type of controlled airspace „E*“ where ATC is able to steer traffic (to make sure it doesn‘t interfere with IFR traffic in E above) but is not responsible for seperation to lower IFR traffic in G.
Malibuflyer wrote:
Therefore the German solution is to not have any IFR traffic in these 1000ft. And exactly for that reason there is a „1000ft gap“ between the airspace G you could fly IFR in and the part of the airpace E where ATC would let you fly IFR. This problem technically is real – and ATC in a country can only decide between not to care for seperation in this piece of airspace or doing what the Germans do and not let someone pass through this „1000ft gap“ under IFR.
It sounds like German ATC is overstating the separation requirements. With exactly the same reasoning the requirement to separate IFR/VFR in class C would make it impossible for IFR traffic to climb or descend over a horizontal boundary between class C and class E, or indeed for IFR traffic to fly level in the class C airspace within 1000 ft of the boundary!
That is actually right!
For the “overall enroutel Charlie” above FL100 in Germany, the lowest usable level FL110 anyways – leaving 1000ft separation to the VFR-traffic in Echo.
That leaves us with the challenge of climbing or descending through the last 1000ft. The difference to the golf/echo boundary is, that there is radar coverage in the upper part of Echo and with the exception of very few gliders at FL100 all traffic has a transponder turned on (one of the reasons for the German transponder requirement for motor powered planes above 5000ft). Therefore they can vector you around traffic (also assuming that this traffic is not an extremely fast Jet on a VFR-flight at FL100 that gets close to you faster than ATC can vector you away…). I actually had already the situation that ATC kept me at FL110 due to lower traffic passing by …
And I can’t really see, that they are overstating requirements!?! Or do you know of any regulation, that separation minima only apply to aircraft in the same airspace class?
In Germany, the MRVA is above minimum terrain safe level in many many places.
It is always at least 500 ft above the lower class E limit, and in an area where class E starts at 2,500ft AGL that means 3000ft above ground. Sure the IFR minimum altitude is for 5nm around the aircraft, not above spot elevation, but in many places this is easily met.
Also, the minimum safe altitude of 1000 ft does not apply when necessary for take off or landing.
This peculiarity is simply regulatory inertia and has zero justification. And as many unjustified rules, it is routinely ignored.
Malibuflyer wrote:
And I can’t really see, that they are overstating requirements!?! Or do you know of any regulation, that separation minima only apply to aircraft in the same airspace class?
Both in SERA, PANS-ATM and ICAO Annex 11, this is phrased in a way which is ambiguous and needs interpretation. Many countries do not interpret the separation requirements in that way, so you can’t simply take for granted that the German interpretation is correct and other interpretations are wrong.
In any case, while not assigning cruising levels within a 1000 ft band of a horizontal CAS/OCAS boundary makes some kind of sense, restricting descents (or climbs) across the boundary do not. OCAS, there is no separation. An aircraft wanting to descend out of controlled airspace obviously assumes no separation of any kind the second it leaves CAS, so why is it so important to provide separation for the last 1000 ft of descent that failure to do so means that the descent must be prohibited?
Finally, Germany does permit some climbs/descents from/into class G airspace (namely from/to instrument airports OCAS). Why is it ok in these cases but not in others?
Because it limits IFR in class Golf to approaches to and departures from these airfields (which they have to do; otherwise, they would have to limit IFR ops to airports in class D only) and still bans it everywhere else (which is simply what they WANT, for dogmatic reasons).
Airborne_Again wrote:
Finally, Germany does permit some climbs/descents from/into class G airspace (namely from/to instrument airports OCAS)
Wich ones are you referring to? I obviously haven’t checked all of them, but the ones that come to mi mind either have a TMZ around (so that again ATC at least knows of other traffic) or Echo goes so low that there is no room for legal IFR-traffic with respect to terrain separation within the underlying Golf anyways.Airborne_Again wrote:
In any case, while not assigning cruising levels within a 1000 ft band of a horizontal CAS/OCAS boundary makes some kind of sense, restricting descents (or climbs) across the boundary do not.
It might make common sense but not “legal sense”. Either you assume that separation is the responsibility of ATC even in the lower 1000ft of CAS or not. In both cases it doesn’t matter at all if a plane is in descend or not.Airborne_Again wrote:
An aircraft wanting to descend out of controlled airspace obviously assumes no separation of any kind the second it leaves CAS, so why is it so important to provide separation for the last 1000 ft of descent that failure to do so means that the descent must be prohibited?
Because that is the rules. In aviation you could always argue, that hard limits don’t make sense. You can fly exactly to the limit of airspace Charlie w/o permission so why it is important if you accidentally enter it by 100ft? If that is not relevant, why is it relevant if you enter it by 500ft? That is not only true for aviation: Is it really so much more dangerous to drive 130km/h on a Swedish highway that you get busted while it’s totally ok to drive 120km/h? Limits are always kind of arbitrary but they help.
And yes: It does make sense that ATC can’t fly you directly into other traffic and the pretend, “yes, but it was on the other side of the airspace border”.
Yes, German ATC has a very conservative interpretation of the rules, but if you take them by the words, it is not wrong. While it’s easy to blame German ATC it would be much more worthwhile to make EASA (or even ICAO) simply change/clarify the rules – a simple “in any airspace it’s the pilots own responsibility to maintain separation to any other traffic outside controlled airspace” would avoid that discussion once and forever.
I suspect, however, that then we would have discussions here because pilots who get busted for loss of separation will complain here that this is unfair as they only followed their clearance (as they have to do in CAS) and did not see the traffic below…
Sorry, but it would be EXTREMELY easy to provide IFR-IFR separation procedurally, for example by only clearing one aircraft at the time in a given ATC sector. Which is , BTW, what the US does.
There is no justification at all other than resistance to change.
How is it possible for a pilot to maintain separation OCAS if they don’t know the exact position and altitude of other aircraft? Are you suggesting mandatory ADSB in and out or TCAS for all aircraft?
I like the way IFR is handled here. File FPL (although can be done in the air) take off from an uncontrolled, unmanned aerodrome, OCAS. Make contact as soon as possible (radio range) with an ATS service whilst climbing to 3000’. Ask for clearance. Clearance will usually be given quickly to some point in the direction I am going and then I go in and out of CAS just being told you are leaving CAS and rejoining CAS as needed with onward clearances as I go. All very easy and relaxed. The thought that on an IFR fpl in IMC being dropped out of ATS services and having to decide who you call next and whether or not you are likely to infringe either airspace or separation is a nightmare.
