Primarily for general aviation discussion, but other aviation topics are also welcome.
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#1695669
Aeronca Alan wrote:
It fails to mention that SVFR is not allowed in a CTA, only a CTR.

No, CAP 1779 clearly mentions that in 2.2 (and perhaps elsewhere).

Yes sorry, that was poorly phrased, the do state it as a fact but don't then proceed to the (obvious to me anyway) adverse consequences.
I'm still trying to understand the bigger point you are making:
you won't be able to fly legally in the 1500 foot CTAs at either end if the cloud is 2500 or less.


I'm not clear what you're asking? You can't be SVFR in the CTA and if cloud is below 2500 feet you can't be VFR either (legally) in the Cardiff 1500 foot CTRs following the proposed changes (and I've just noticed you even have a 1000 foot one as well)! If you can't fly through the CTA how are you going to get to the CTR to experience the new-found joy of SVFR? It's the (legally ) bit that seems to provoke debate (or not)! as to whether it actually matters.
Alan
#1695672
James Chan wrote:Yet cloud base is measured at the aerodrome, which can have a very different elevation to where any other CTA is.

And clouds often don't have uniform base and coverage either.

Well it/they can of course but c'mon, in practice, at most UK airports, most of the time, they won't. Surely this is just fudging around trying to find reasons not to object to the proposed change rather than acknowledging and tackling the fundamental problem?

I'm struggling with the logic of your other post but maybe all will be clear when I come back from my bike ride :)
#1695675
The fundamental issue to address IMHO is that someone could look at reducing vertical cloud distance to 500ft.

c'mon, in practice, at most UK airports, most of the time, they won't.


I think we'll have to agree to disagree here.
#1695691
flybymike wrote:The whole idea is potty.
Clear of cloud in sight of the surface has never been a problem.
It doesn’t need fixing.


“The SERA Class D VMC requirements are in directly applicable EU law. This option does not satisfy this requirement and is therefore rejected.”

CAA seems to saying “no change” is not an option within their remit? Is that right or could they just extend the exemption again (legally)?
#1695702
James Chan wrote:The fundamental issue to address IMHO is that someone could look at reducing vertical cloud distance to 500ft.

c'mon, in practice, at most UK airports, most of the time, they won't.


I think we'll have to agree to disagree here.

500 feet would be better but is surely a non-starter as it would need a derogation from SERA which apparently we can’t have. We already have a better one which works fine, but are about to give it up.

Regarding cloudbase variation, ignoring wierd and wonderful airports, and within the context of the discussion, I think I'd come away from a wager a wealthy man but yes, probably we will need to just differ on that one as it is not really central to the debate.
Alan
#1696108
Aeronca Alan wrote:At the moment, Cardiff ATC in effect, and rightly or wrongly (it's academic), separate VFR traffic from IFR traffic. I don't see what the difference will be if I am in receipt of a SVFR clearance. Is there a difference?
I'm guessing that what you're referring to here is the routine practice in the UK of ATC units in Class D providing vertical separation of 1000ft between IFR traffic and VFR traffic that's below it. It's not in any rules but it's standard practice. But what they do not and cannot do is separate IFR and VFR traffic horizontally - i.e. by a specified distance. All they do is provide traffic information to both parties and issue a clearance limit to the VFR traffic to ensure there is always some horizontal distance between them.

The difference with an SVFR clearance is that ATC must provide minimum 3nm horizontal separation between IFR and SVFR traffic. The separation can't be vertical because SVFR clearances are always "not above xxxx ft" so the traffic could be at any level below that.

So on a SVFR clearance, if you're crossing the airport, or indeed departing from/arriving at it, there has to be a minimum 6nm gap between IFR inbounds/outbounds to allow your transit. In practice it has to be significantly more than that because it's a dynamic situation with inbounds closing on the airport at around 3nm/min. The result will be SVFR traffic orbiting 3nm away for as long as it takes for a gap to emerge, then a frantic rush to get across to 3nm the other side of the runway. For a typical light aircraft that will take a minimum of 4 minutes - much more if you're given the crossing clearance when you're at the back side of an orbit and you're crossing against a headwind. ATC at many locations will quickly conclude that the controller workload in managing this is unacceptable and they will simply stop issuing SVFR clearances.

You have until Friday to submit your response to the CAA. I hope as many of you as possible will submit.

NS
callump, Talkdownman liked this
#1696505
Unless I've misunderstood something the separation criteria for IFR versus SVFR is 3nm and 500ft as long as both aircraft are talking to the same controller. That surely can't be a huge task for a controller can it?? So one key point might be to establish standard routes for SVFR and VFR traffic across the class D?
#1696508
It sometimes certainly feels as though the “bubble” placed around CAT is currently somewhat bigger than that.
#1696515
johnm wrote:Unless I've misunderstood something the separation criteria for IFR versus SVFR is 3nm and 500ft as long as both aircraft are talking to the same controller. That surely can't be a huge task for a controller can it?? So one key point might be to establish standard routes for SVFR and VFR traffic across the class D?
3nm or 1000ft. But for the typical SVFR transit through a Class D CTR, crossing over the controlling airport, the separation can only be horizontal because the SVFRs are all on a "not above" clearance and the IFRs are all descending/climbing through those levels. So the controller has to keep any SVFR crosser at least 3nm away from the approach and climb-out paths until there's a gap in both arrivals and departures long enough for the SVFR to fly the 6nm+ from one side of the airfield to the other. That's at least four minutes during which there can be no IFR movements. And before that crossing, the controller will have to keep the SVFR orbiting and monitor its position, with all the extra RT and workload that involves.
The airport bosses who ultimately pay the controllers to expedite their airline traffic will very quickly get wise to any delays to IFRs caused by SVFR transits and will issue edicts to their ATC contractors that no SVFR transit requests are to be granted.
There are already standard routes for VFR/SVFR transits through every Class D zone. the proposed rule will effectively force all of them to be flown SVFR, causing the delays outlined above.
#1696522
Given the altitude restrictions then 3 nm seems to be a requirement as you state but would that be any different in practical terms from what controllers do today?? It would be good to get a controller perspective on this.
#1696538
If the ATCO is continuously visual with both the SVFR and the IFR inbounds/outbounds they can provide reduced separation in the vicinity of the aerodrome which makes it effectively like a normal VFR crosser but they’d need to be visual before radar separation is lost.
#1696569
From UK Manual of Air Traffic Services Part 1 (CAP493).....

Section 1 Chapter 2
8 Special VFR
8A. Conditions
8A.1
A Special VFR clearance is issued when requested by a pilot or when it is notified in the UK AIP for a particular type of operation. Before issuing such a clearance a controller must consider the prevailing traffic conditions, the extent of the proposed flight and the availability of air-ground communications. Special VFR flights are not to hinder normal IFR flights


My bolding.
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