IFR or VFR?
I don't know about corrigiendum letters as such. I've got the downloadable CAP 493 with Amendment 57. It mentions no VFR clearances when the vis is below 5000 m but I can't see anything about cloud ceiling.
I'm not just trying to be nitpicky about details, though you know too well that's in my nature
. Under ICAO rules for controlled airspace, the minimum VFR level permitted is 500 ft and the minimum vertical separation from cloud is 1000 ft. Thus VFR is impossible if the ceiling is less than 1500 ft. The UK has neither rule and so VFR is, in principle, possible with such a ceiling.
The ICAO rule anticipates class E control zones where a clearance wouldn't otherwise be required. It forces a flight in such circumstances to get a SVFR clearance. In the UK, the same can be achieved by instructions to ATC, as all the flights in the CTR require a clearance.
I'm not just trying to be nitpicky about details, though you know too well that's in my nature
. Under ICAO rules for controlled airspace, the minimum VFR level permitted is 500 ft and the minimum vertical separation from cloud is 1000 ft. Thus VFR is impossible if the ceiling is less than 1500 ft. The UK has neither rule and so VFR is, in principle, possible with such a ceiling. The ICAO rule anticipates class E control zones where a clearance wouldn't otherwise be required. It forces a flight in such circumstances to get a SVFR clearance. In the UK, the same can be achieved by instructions to ATC, as all the flights in the CTR require a clearance.
Thank you. I'm now totally baffled. Amendment 59 reads:
(change bars indicate that the parts about cloud ceiling are insertions in Amendment 59)
The corrigiendum reads:
So this raises two questions:
1) Why would they insert the 1500 ft bit? [Don't tell me -- it was that bl
dy ICAO safety audit, wasn't it...]
2) Why would they delete it in the second part but not the first?
It's really quite awful drafting. Reading the two bits together, does this mean, as Vintage ATCO suggests, that there is a 1500 ft ceiling limit on VFR in the CTR or not?
8.5 When the reported meteorological visibility at the aerodrome falls below 5000 m, and/or the cloud ceiling is less than 1500 feet, pilots of aircraft, other than helicopters, operating under VFR inbound to, or outbound from airfields situated in Class D control zones must be advised and their intentions sought. No further VFR clearances are to be issued to any inbound or outbound traffic, in these circumstances, until such time as the reported meteorological visibility at the aerodrome reaches or exceeds 5000m and the cloud ceiling is 1500 feet or above.
The corrigiendum reads:
There is an error in Amendment 59 to CAP 493 Manual of Air Traffic Services (MATS) Part 1, Section 3, Chapter 1, page 5, paragraph 8.5. The last sentence should be corrected to finish with a full stop after “exceeds 5000 m” and the remaining words deleted.
“No further VFR clearances are to be issued to any inbound or outbound traffic, in these circumstances, until such time as the reported meteorological visibility at the aerodrome reaches or exceeds 5000m. [and the cloud ceiling is 1500 feet or above].”
“No further VFR clearances are to be issued to any inbound or outbound traffic, in these circumstances, until such time as the reported meteorological visibility at the aerodrome reaches or exceeds 5000m. [and the cloud ceiling is 1500 feet or above].”
1) Why would they insert the 1500 ft bit? [Don't tell me -- it was that bl
dy ICAO safety audit, wasn't it...]2) Why would they delete it in the second part but not the first?
It's really quite awful drafting. Reading the two bits together, does this mean, as Vintage ATCO suggests, that there is a 1500 ft ceiling limit on VFR in the CTR or not?
aceatco, retired
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We are not permitted to issue a VFR clearance (in a Class D CTR) if the vis is less than 5km and/or the cloud ceiling is less than 1500ft.
I don't know why the second 1500ft was removed.
I don't know why the second 1500ft was removed.
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Finally had a chance to study all the views to this thread after a busy xmas. Hope all had a good time and are still within MTOW!
Judging by all the detailed posts, it seems that there certainly is confusion within the VFR regulations but these confusions seem to concern mainly whether or not a take off in the conditions stated is legal (it appears to be). But is the rest of the flight legal and how do you manage the flight if it subsequently becomes IMC/IFR.
Even though a departure may be legal in those conditions, the en route phase certainly would not be given that maintaining clear of clouds would invariably cause a breach of Rule 5.
So, why depart then VFR? As W Collins clearly points out, a big reason appears to be the wish not to incur route charges and who would not agree? You are not receiving any services so why pay? Perhaps then we should take this up with the powers that be but my life is not long enough to wrestle that one out of CAA, Brussels, whoever....
But is it sensible to depart without any prior arrangement with a radar unit set up? What about the possibility that somebody just might be coming the other way? To quote W Collins again, there have been no instances of collision whilst flying IMC outside of controlled airspace....this I presume is true but I have knowledge of several instances recently where collisions appear to have been narrowly avoided. Circumstances varied but some were saved by TCAS, some by timely radio calls coincidentally and some by radar. So the danger is there. The 'big sky' theory pointed out by some contributors to this post is true...but the sods law also applies.
What about radar then? At best in the UK coverage is patchy and although the controllers have the best of intentions, invariably you are offered 'Radar Information limited due to range,altitude,controller workload or poor radar performance'. Incidentally, I thought RIS or RAS was available.....where is the official definition of 'Limited radar'?!! Indeed, some of the close ones noted have been receiving a service so still you are not guaranteed safety but arming oneself with all the tools available must surely increse your safety margin.
In respect of W Collins worry that he was the 'target' of this post, this is not the case. The Metar given was a representative one used as an example. Indeed, I have seen departures in conditions worse than shown, which is the impetus for this thread. However, It is recognised that there is a difference between the crazies who launch ill equipped and under rated in a 150 to that of the experienced IR pilots in the right equipment who have contributed to this thread.
My summary then...no matter how experienced, or what you are flying, get a radar service if its available and you're IMC....the route charge (even if it ever finds you) will be small change if it's helped you avoid hitting me coming the other way! And turn that Mode C on!
Woss.
ps. Is it true that you cannot fly IMC outside controlled airspace in France?
Judging by all the detailed posts, it seems that there certainly is confusion within the VFR regulations but these confusions seem to concern mainly whether or not a take off in the conditions stated is legal (it appears to be). But is the rest of the flight legal and how do you manage the flight if it subsequently becomes IMC/IFR.
Even though a departure may be legal in those conditions, the en route phase certainly would not be given that maintaining clear of clouds would invariably cause a breach of Rule 5.
So, why depart then VFR? As W Collins clearly points out, a big reason appears to be the wish not to incur route charges and who would not agree? You are not receiving any services so why pay? Perhaps then we should take this up with the powers that be but my life is not long enough to wrestle that one out of CAA, Brussels, whoever....
But is it sensible to depart without any prior arrangement with a radar unit set up? What about the possibility that somebody just might be coming the other way? To quote W Collins again, there have been no instances of collision whilst flying IMC outside of controlled airspace....this I presume is true but I have knowledge of several instances recently where collisions appear to have been narrowly avoided. Circumstances varied but some were saved by TCAS, some by timely radio calls coincidentally and some by radar. So the danger is there. The 'big sky' theory pointed out by some contributors to this post is true...but the sods law also applies.
What about radar then? At best in the UK coverage is patchy and although the controllers have the best of intentions, invariably you are offered 'Radar Information limited due to range,altitude,controller workload or poor radar performance'. Incidentally, I thought RIS or RAS was available.....where is the official definition of 'Limited radar'?!! Indeed, some of the close ones noted have been receiving a service so still you are not guaranteed safety but arming oneself with all the tools available must surely increse your safety margin.
In respect of W Collins worry that he was the 'target' of this post, this is not the case. The Metar given was a representative one used as an example. Indeed, I have seen departures in conditions worse than shown, which is the impetus for this thread. However, It is recognised that there is a difference between the crazies who launch ill equipped and under rated in a 150 to that of the experienced IR pilots in the right equipment who have contributed to this thread.
My summary then...no matter how experienced, or what you are flying, get a radar service if its available and you're IMC....the route charge (even if it ever finds you) will be small change if it's helped you avoid hitting me coming the other way! And turn that Mode C on!
Woss.
ps. Is it true that you cannot fly IMC outside controlled airspace in France?
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but I have knowledge of several instances recently where collisions appear to have been narrowly avoided. Circumstances varied but some were saved by TCAS, some by timely radio calls coincidentally and some by radar.
I thought RIS or RAS was available.....where is the official definition of 'Limited radar'?!!
1.6 Limiting a Service
1.6.1 Outside controlled airspace in circumstances where controllers cannot continue to provide the following primary requirements:
a) traffic information and traffic avoidance in respect of all conflicting unknown aircraft for a radar advisory service; and
b) traffic information in respect of all conflicting unknown aircraft for a radar information service, controllers may elect to continue to give the service by limiting the extent to which it is provided.
1.6.2 Controllers must inform pilots when they limit the service and ensure that pilots are made fully aware of the implications of any limitation.
1.6.3 In particular the service should be limited when:
a) the aircraft is operating within 10 miles* of:
i) the edge of the radar display;
ii) weather clutter; or
iii) permanent echoes.
b) the aircraft is operating in an area of high traffic density;
c) the aircraft is operating near to the limits of solid radar cover; or
d) The service is being provided using secondary radar only.
* Except where the range selected (e.g. 3, 10, 15 miles) will not enable these criteria to be met during an approach to an aerodrome.
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Chiil Monster
Thank you for the MATS info re Limited Radar.
If you don't mind me saying so, this statement is a bit daft. Obviously you don't know in all cases if a collision would have occurred. But given that two aircraft in IMC are flying converging tracks neither of which are receiving separation from an ATC unit, it would seem that there is a risk of collision even if thankfully it did not occur. It does not matter how 'adjacent' they are: they are not separated by anyone, they are not talking to anyone so the risk is there.
Thank you for the MATS info re Limited Radar.
But - how do you know these 'instances' would have resulted in collisions or merely the aircraft being a bit too 'adjacent' than the occupants would have liked. You only know aircraft were in danger of colliding by either a) it actually happening or b) accurate simulation / modelling after the event. As such you can't really make the statement above - it just isn't true.
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Woss
But you didn't say that originally. You said
And I stick by my original answer. It's not daft unless refuted by FACTS and hearsay doesn't constitute fact. If you know of such circumstances then by all means enlighten us - but 'knowing' and 'summising' which is what, to be honest, your original statement is nearer to I would think, are two totally separate things. Your use of the word 'appear' would back that up.
I mentioned simulation/modelling of the events to derive information on whether the collision would have happened. That's because that is what the UK Airprox board is there for and what they do. Leaving them as the final arbiters of whether a collision would have taken place rather than summising whether it would is a far more sensible idea in my honest opinion. If those reports are what you're referring to as the possibles that you know of then fair enough - but if you're referring to other events then we're back to the summising verses fact situation.
Just because aircraft aren't separated doesn't mean that they're going to hit. There was such a thing on my procedural course as a 'technical' loss of separation. The aircraft may have been 20 miles apart - but if you didn't have in place a laid down method of separation as per MATS pt 1 then it was deemed a technical loss, even though they wouldn't hit in a month of sundays.
Facts count, nothing else.
But given that two aircraft in IMC are flying converging tracks neither of which are receiving separation from an ATC unit, it would seem that there is a risk of collision even if thankfully it did not occur.
but I have knowledge of several instances recently where collisions appear to have been narrowly avoided. Circumstances varied but some were saved by TCAS, some by timely radio calls coincidentally and some by radar.
I mentioned simulation/modelling of the events to derive information on whether the collision would have happened. That's because that is what the UK Airprox board is there for and what they do. Leaving them as the final arbiters of whether a collision would have taken place rather than summising whether it would is a far more sensible idea in my honest opinion. If those reports are what you're referring to as the possibles that you know of then fair enough - but if you're referring to other events then we're back to the summising verses fact situation.
Just because aircraft aren't separated doesn't mean that they're going to hit. There was such a thing on my procedural course as a 'technical' loss of separation. The aircraft may have been 20 miles apart - but if you didn't have in place a laid down method of separation as per MATS pt 1 then it was deemed a technical loss, even though they wouldn't hit in a month of sundays.
Facts count, nothing else.
Last edited by Chilli Monster; 28th Dec 2003 at 22:53.
We are not permitted to issue a VFR clearance (in a Class D CTR) if the vis is less than 5km and/or the cloud ceiling is less than 1500ft.
form, it says (first sentence) that you must advise VFR flights if the vis drops below 5000 m or the ceiling is less than 1500 ft. But (second sentence) if the latter is the case and the visibility is at or above 5000 m, you can issue a VFR clearance.
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Bookworm, actually vintage atco is correct. The CAA has got its self into a it of a muddle and have amended the ammedment to the the ammendment and my understanding is if the ceiling is below 1500ft you cant issue a vfr clearance to an aircraft taking off and landing in an airport in class D.
So this has been ammended again and the rest of the sentance put back in.
So this has been ammended again and the rest of the sentance put back in.
The corrigiendum reads:
quote:
--------------------------------------------------------------------------------
There is an error in Amendment 59 to CAP 493 Manual of Air Traffic Services (MATS) Part 1, Section 3, Chapter 1, page 5, paragraph 8.5. The last sentence should be corrected to finish with a full stop after “exceeds 5000 m” and the remaining words deleted.
“No further VFR clearances are to be issued to any inbound or outbound traffic, in these circumstances, until such time as the reported meteorological visibility at the aerodrome reaches or exceeds 5000m. [and the cloud ceiling is 1500 feet or above].”
--------------------------------------------------------------------------------
quote:
--------------------------------------------------------------------------------
There is an error in Amendment 59 to CAP 493 Manual of Air Traffic Services (MATS) Part 1, Section 3, Chapter 1, page 5, paragraph 8.5. The last sentence should be corrected to finish with a full stop after “exceeds 5000 m” and the remaining words deleted.
“No further VFR clearances are to be issued to any inbound or outbound traffic, in these circumstances, until such time as the reported meteorological visibility at the aerodrome reaches or exceeds 5000m. [and the cloud ceiling is 1500 feet or above].”
--------------------------------------------------------------------------------
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Bookworm, I trust that you meant that the discussion on CTRs should stop there and not the whole thread, cos I would like to come back to the discussion between Woss and Chilli.
The fact of the matter is that no such collision has taken place in UK airspace since the war. There is no better argument on risk than the actuarial one.
Some ATCOs and and Authorities seem to treat a "loss of separation" as seriously as a collision. This is like my wife's reaction to losing a child in the park. Just because you can't see him doesn't necessarily mean that he has been abducted or run-over, just as loss of separation doesn't mean the worst has happened.
I still feel safer in the class G corridor between BIG and OCK in a 2000' cloudbase at 2300' than I do at 1900'...and I believe that feeling of safety to be justified by the realities of the situation.
Will
The fact of the matter is that no such collision has taken place in UK airspace since the war. There is no better argument on risk than the actuarial one.
Some ATCOs and and Authorities seem to treat a "loss of separation" as seriously as a collision. This is like my wife's reaction to losing a child in the park. Just because you can't see him doesn't necessarily mean that he has been abducted or run-over, just as loss of separation doesn't mean the worst has happened.
I still feel safer in the class G corridor between BIG and OCK in a 2000' cloudbase at 2300' than I do at 1900'...and I believe that feeling of safety to be justified by the realities of the situation.
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I don't think its the ATCOs who necessarily treat a minor erosion as seriously as a collision, its more likely those pesky automated computer systems and the associated mountain of paperwork.
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I had a near miss yesterday, flying IFR from Beccles to Leicester in the snow and god knows what else another aircraft apparantly not flying a Quadrantal rule passed over the top at me by no more than 50ft. Made my bum clench a little a bit!
Forwardn viz at the time was around 250-500m.
The big skies theory is great if everyone flies to the same set of rules, unfortunatly yesterday it proves that they do not!
Unfortunatly all of the LARS units that I flew over were closed as well which mad a RADAR service impossible. I cant believe the want GA to pay for LARS!
Still a near miss is better than a hit!
Forwardn viz at the time was around 250-500m.
The big skies theory is great if everyone flies to the same set of rules, unfortunatly yesterday it proves that they do not!
Unfortunatly all of the LARS units that I flew over were closed as well which mad a RADAR service impossible. I cant believe the want GA to pay for LARS!
Still a near miss is better than a hit!
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bose
I rest my case.....you didn't hit him
It is very difficult to get two aeroplanes in the same place at the same time unless they are over a beacon at a fixed altitude (either whole numbers of 500' or scud running) which is why I avoid both.
Will
I rest my case.....you didn't hit him
It is very difficult to get two aeroplanes in the same place at the same time unless they are over a beacon at a fixed altitude (either whole numbers of 500' or scud running) which is why I avoid both.
Will
I had a near miss yesterday, flying IFR from Beccles to Leicester in the snow and god knows what else another aircraft apparantly not flying a Quadrantal rule passed over the top at me by no more than 50ft. Made my bum clench a little a bit!
Forwardn viz at the time was around 250-500m.
The big skies theory is great if everyone flies to the same set of rules, unfortunatly yesterday it proves that they do not!
Forwardn viz at the time was around 250-500m.
The big skies theory is great if everyone flies to the same set of rules, unfortunatly yesterday it proves that they do not!
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I am not sure that compliancewith the quad rule reduces the probability of a mid-air (implying a fatal accident).
It would make an interesting exercise in probability theory to work out whether IN IMC a mid-air is more or less likely between two objects flying head-on or the same two objects flying in the same direction.
I don't think the case is at all obvious. My feeling is that there is no difference at all.
(I am assuming that a 150kt plane going up the back of a 100kt one will be as good as a head-on)
If there is SOME visibility, then the quad rule should mean you have more time to see the other one. But given the poor visibility of GA planes (which is something all pilots and passengers notice pretty well right away) I don't think this is a factor unless the vis is a lot better than 250m. Also if somebody is being smart and is flying in marginal VMC with their landing/taxi lights on, you won't see those from behind. Also if somebody is closing with you at say a 20deg angle you probably won't see them anyway because few pilots twist their neck that far when looking for traffic.
I think by far the main benefit of the quad rule is for airliners: with TCAS you get a lot more time to act. But we all know that in GA a lot of people don't have transponders, or if they do they have them turned off. I flew today for 30 mins under an RIS, saw not one of 5 or so targets, and not one of them had Mode C on (I was VMC on top at FL050 and they were probably below).
I am not sure that compliancewith the quad rule reduces the probability of a mid-air (implying a fatal accident).
It would make an interesting exercise in probability theory to work out whether IN IMC a mid-air is more or less likely between two objects flying head-on or the same two objects flying in the same direction.
I don't think the case is at all obvious. My feeling is that there is no difference at all.
(I am assuming that a 150kt plane going up the back of a 100kt one will be as good as a head-on)
If there is SOME visibility, then the quad rule should mean you have more time to see the other one. But given the poor visibility of GA planes (which is something all pilots and passengers notice pretty well right away) I don't think this is a factor unless the vis is a lot better than 250m. Also if somebody is being smart and is flying in marginal VMC with their landing/taxi lights on, you won't see those from behind. Also if somebody is closing with you at say a 20deg angle you probably won't see them anyway because few pilots twist their neck that far when looking for traffic.
I think by far the main benefit of the quad rule is for airliners: with TCAS you get a lot more time to act. But we all know that in GA a lot of people don't have transponders, or if they do they have them turned off. I flew today for 30 mins under an RIS, saw not one of 5 or so targets, and not one of them had Mode C on (I was VMC on top at FL050 and they were probably below).
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Bookworm,
I am sorry but you twisted my statement I said APPARANTLY not flying a quadrantal, I did not say that anything had been BROKEN. The other aircraft appeared to be in straight and level flight for the few short seconds that I saw him and made no attempt at avoiding action so I would guess did not see me.
I was flying at FL45 heading 290.
I was not making a complaint about the other aircraft who could well have been climbing or decscending, I was merely making an observation about a near miss.
My point was that despite this near miss in the open FIR without radar it was still a miss.
I am sorry but you twisted my statement I said APPARANTLY not flying a quadrantal, I did not say that anything had been BROKEN. The other aircraft appeared to be in straight and level flight for the few short seconds that I saw him and made no attempt at avoiding action so I would guess did not see me.
I was flying at FL45 heading 290.
I was not making a complaint about the other aircraft who could well have been climbing or decscending, I was merely making an observation about a near miss.
My point was that despite this near miss in the open FIR without radar it was still a miss.
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I think by far the main benefit of the quad rule is for airliners: with TCAS you get a lot more time to act.
The Quadrantal rule was there long before airways and radar was universal, and was mainly for separating Doves and DC4s.
Airliners nearly all fly on airways nearly all the time. The Quadrantal rule does not apply to airways.
The Quadrantal rule preceded TCAS by a long, long time (let's guess fifty years.)
No, the quadrantal rule is there to reduce the probability of collisions. My own view is that if aircraft flew at a level determined by the last letter of its registration (thus introducing more randomness) it would be more effective, but, as I keep saying, there really is no problem. It ain't bust, let's not fix it.
Will