New guidance on unknown traffic in Class D
Bookworm
You say:
"Yes, in the simplest case, it's clearly possible to fly SVFR if you're the only aircraft around. But if there are more than one, doesn't even "reduced separation" between SVFR flights place a rather heavier operational burden on ATC than simple VFR in the circuit?"
Quite correct - although I would phrase it as "more responsibility". However, an alternative is to place the responsibility for maintaining "own" separation on the pilot(s) - another form of "reduced separation int he vicinity...". That ploy will often reduce the circuit activity to an appropriate level!
You say:
"Yes, in the simplest case, it's clearly possible to fly SVFR if you're the only aircraft around. But if there are more than one, doesn't even "reduced separation" between SVFR flights place a rather heavier operational burden on ATC than simple VFR in the circuit?"
Quite correct - although I would phrase it as "more responsibility". However, an alternative is to place the responsibility for maintaining "own" separation on the pilot(s) - another form of "reduced separation int he vicinity...". That ploy will often reduce the circuit activity to an appropriate level!
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Of course just to make it all even more confusing, the ability to accept a VFR clearance in Class D when flying just below the cloud is limited to UK pilots.
A visiting pilot who is only legally permitted to fly in VMC as per the ICAO rules could not accept such a VFR clearance unless they were 1000ft below the cloud.
So the argument about making it easier for VFR flights only applies to some of the flights......unless the airspace is restricted to UK pilots only!
It's like the UK pilots who have to be in sight of the surface at all times not being able to fly VFR on top in France despite the fact that French pilots with the same licence (JAA) can do so.
So perhaps the tower controller needs to not simply say "the visibility is XXX do you request IFR of Special VFR........but also to visiting aircraft......the ceiling is XXX do you request IFR or special VFR.
Makes for a very simple system indeed.
Regards,
DFC
A visiting pilot who is only legally permitted to fly in VMC as per the ICAO rules could not accept such a VFR clearance unless they were 1000ft below the cloud.
So the argument about making it easier for VFR flights only applies to some of the flights......unless the airspace is restricted to UK pilots only!
It's like the UK pilots who have to be in sight of the surface at all times not being able to fly VFR on top in France despite the fact that French pilots with the same licence (JAA) can do so.
So perhaps the tower controller needs to not simply say "the visibility is XXX do you request IFR of Special VFR........but also to visiting aircraft......the ceiling is XXX do you request IFR or special VFR.
Makes for a very simple system indeed.
Regards,
DFC
Of course just to make it all even more confusing, the ability to accept a VFR clearance in Class D when flying just below the cloud is limited to UK pilots.
The Chicago Convention provides for aircraft to obey the Rules of the Air of the state whose airspace they are in, not the state of registration, nor the state of licence issue/validation of the crew (which will usually be the state of registration).
The rather screwy extraterritorial provision of the Rules of the Air Regulations need to be taken with a pinch of salt and a liberal dose of Art 84(3)(b). Its intention is to provide some framework for behaviour over the high seas.
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Just out of interest, to get back to the original points regarding avoiding unknown contacts in Class D control zones from surface upward - any slow moving primary only contact is almost definitely an aircraft (especially if no class G above).
Can anyone supply me with the old rules applying to Special rules zones etc that were in effect in late 80s before the new classifications came in - especially with regard to avoiding unknown contacts.
Final theoretical question - if you as an approach controller saw a slow-moving primary return in your class D control zone (no class G above), would you avoid it? I know the rules say you can, but would you? I'm thinking zone infringers etc.
Can anyone supply me with the old rules applying to Special rules zones etc that were in effect in late 80s before the new classifications came in - especially with regard to avoiding unknown contacts.
Final theoretical question - if you as an approach controller saw a slow-moving primary return in your class D control zone (no class G above), would you avoid it? I know the rules say you can, but would you? I'm thinking zone infringers etc.
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Bookworm,
Pilots are required to comply with the rules of the country over which they are flying or the rules of the country where the aircraft is registered whichever is the most restrictive
By following that requirement, a pilot ensures that none of the rules of any country are infringed at any time.
As I said, the perfect example is the UK pilot flying outside the UK.
The ICAO VMC criteria permit VFR flight above an overcast. The basic UK PPL is prevented from flying as such by UK law. Thus in that case even if the pilot is Flying in France, it is UK law that is the most restrictive and what limits the pilot.
Simply by not flying above an overcast, the pilot will comply with both French and UK law so there is no problem.
Going back to the Class D issue. If a French pilot for example refuses to accept a VFR clearance unless they can be 1000ft vertically from cloud in Class D then they are not breaking any UK law.....and also they are not breaking any French requirement.....or any ICAO requirement because OCAI clearly requires such a separation unless a special VFR clearance is obtained.
Thus they are limited by the most restrictive requirement which in this case is from outside the UK system.
Thus, the UK local operation of a sub ICAO airspace VMC requirement is only good for UK pilots and pilots of other countries that have the same VMC requirements..............Does anyone know of any other countries in Europe that have Class D VMC criteria below the ICAO requirements?
Regards,
DFC
Pilots are required to comply with the rules of the country over which they are flying or the rules of the country where the aircraft is registered whichever is the most restrictive
By following that requirement, a pilot ensures that none of the rules of any country are infringed at any time.
As I said, the perfect example is the UK pilot flying outside the UK.
The ICAO VMC criteria permit VFR flight above an overcast. The basic UK PPL is prevented from flying as such by UK law. Thus in that case even if the pilot is Flying in France, it is UK law that is the most restrictive and what limits the pilot.
Simply by not flying above an overcast, the pilot will comply with both French and UK law so there is no problem.
Going back to the Class D issue. If a French pilot for example refuses to accept a VFR clearance unless they can be 1000ft vertically from cloud in Class D then they are not breaking any UK law.....and also they are not breaking any French requirement.....or any ICAO requirement because OCAI clearly requires such a separation unless a special VFR clearance is obtained.
Thus they are limited by the most restrictive requirement which in this case is from outside the UK system.
Thus, the UK local operation of a sub ICAO airspace VMC requirement is only good for UK pilots and pilots of other countries that have the same VMC requirements..............Does anyone know of any other countries in Europe that have Class D VMC criteria below the ICAO requirements?
Regards,
DFC
Can anyone supply me with the old rules applying to Special rules zones etc that were in effect in late 80s before the new classifications came in - especially with regard to avoiding unknown contacts.
The confusion arose after the UK adopted ICAO Airspace classifications, in 1991? The rules subsequently published in MATS Part 1, regarding the avoidance of unknown aircraft in re-classified Class D Control Zones (old Rule 36 SRZs) were mistakenly changed, but remained the same, according to the UK AIP!
Some time after the Airspace changes, ATC Units were invited to submit comments on any problems or discrepancies to the CAA. (It was hoped that the 'new' airspace classifications would have little impact on procedures then current).
Yours truly, and others, did point out the discrepancy at the time.
Some 13 years later, somebody has finally taken note, and MATS Part 1 once again accords with the AIP!
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SIOTP:
Really? I can think of several Class D zones where your statement would be true only if you put a 'not' between 'definitely' and 'an'.
I presume you meant to say "ignore" rather than "avoid"? The rules don't say "you can avoid it"; they say "you will not give traffic info or avoiding action unless..."
spekesoftly:
Not quite I'm afraid! The AIP text says:
"Traffic information and avoiding action will not be given unless information has been received which indicates that a radar echo may be a particular aircraft which is lost or experiencing radio failure."
The MATS Part 1 text now says:
"Neither avoiding action nor traffic information shall be passed unless radar derived or other information indicates that an aircraft is lost, has experienced a radio failure, or has made an unauthorised penetration of the airspace."
The eagle-eyed among you will spot that the AIP text (which I presume comes from ICAO Doc 4444 - don't have a copy here to consult) says nothing about unauthorised penetrations of the airspace, while MATS says nothing about "particular aircraft". If the AIP text is followed, then controllers could legitimately ignore a primary-only return which appears from nowhere and is not associated with the previous returns from an aircraft which they have been monitoring or which they have been told is an aircraft which is lost or had a radio failure. But the MATS text could, arguably, justify a controller treating any unidentified primary-only return appearing anywhere on the screen as something that requires the giving of traffic information and/or avoiding action.
I see the UK differences from ICAO Doc 4444 are currently under review. Presumably this is one of those differences - although it wasn't previously noted as one.
in Class D control zones from surface upward - any slow moving primary only contact is almost definitely an aircraft
if you as an approach controller saw a slow-moving primary return in your class D control zone (no class G above), would you avoid it? I know the rules say you can
spekesoftly:
somebody has finally taken note, and MATS Part 1 once again accords with the AIP
"Traffic information and avoiding action will not be given unless information has been received which indicates that a radar echo may be a particular aircraft which is lost or experiencing radio failure."
The MATS Part 1 text now says:
"Neither avoiding action nor traffic information shall be passed unless radar derived or other information indicates that an aircraft is lost, has experienced a radio failure, or has made an unauthorised penetration of the airspace."
The eagle-eyed among you will spot that the AIP text (which I presume comes from ICAO Doc 4444 - don't have a copy here to consult) says nothing about unauthorised penetrations of the airspace, while MATS says nothing about "particular aircraft". If the AIP text is followed, then controllers could legitimately ignore a primary-only return which appears from nowhere and is not associated with the previous returns from an aircraft which they have been monitoring or which they have been told is an aircraft which is lost or had a radio failure. But the MATS text could, arguably, justify a controller treating any unidentified primary-only return appearing anywhere on the screen as something that requires the giving of traffic information and/or avoiding action.
I see the UK differences from ICAO Doc 4444 are currently under review. Presumably this is one of those differences - although it wasn't previously noted as one.
NorthSouth,
Glad to see you were paying attention!
As you may also have noticed, the layout and format of the rules regarding 'ATC action with regard to Unknown Aircraft' differs between MATS Pt1 and the UK AIP, which makes comparison of the detail unnecessarily tedious.
Cheers.
Glad to see you were paying attention!
As you may also have noticed, the layout and format of the rules regarding 'ATC action with regard to Unknown Aircraft' differs between MATS Pt1 and the UK AIP, which makes comparison of the detail unnecessarily tedious.
Cheers.
Pilots are required to comply with the rules of the country over which they are flying or the rules of the country where the aircraft is registered whichever is the most restrictive
Chicago Convention 1944
Article 12
Rules of the air
__________ Each contracting State undertakes to adopt measures to insure that every aircraft flying over or maneuvering within its territory and that every aircraft carrying its nationality mark, wherever such aircraft may be, shall comply with the rules and regulations relating to the flight and maneuver of aircraft there in force. Each contracting State undertakes to keep its own regulations in these respects uniform, to the greatest possible extent, with those established from time to time under this Convention. Over the high seas, the rules in force shall be those established under this Convention. Each contracting State undertakes to insure the prosecution of all persons violating the regulations applicable.
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Liverpoolquietly:
I agree it probably wasn't necessary for it to be so tedious but are you suggesting comparison isn't worthwhile? The difference between telling controllers they must vector traffic around every swan or rain shower that pops up out of nowhere, and telling them that they only need give traffic info when they see that light aircraft with the radio failure hang a left and go straight towards the CTR boundary, is huge.
NS
makes comparison of the detail unnecessarily tedious
NS
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Bookworm,
If every country had the exact same requirements then those requirements would be equally restrictive.
That is the whole idea...but then the UK comes along and dreams up it's own version which from a pillot's point of view reduces the safeguards built in by ICAO.
Isn't the teritorial limits of the ANO put somewhere in there....i.e. it applies to all flights over the UK and to UK aircraft where everthey may be? or something like that.
You can be sure that France has similar requirements in it's law.
As for the high seas!
Regards,
DFC
If every country had the exact same requirements then those requirements would be equally restrictive.
That is the whole idea...but then the UK comes along and dreams up it's own version which from a pillot's point of view reduces the safeguards built in by ICAO.
Isn't the teritorial limits of the ANO put somewhere in there....i.e. it applies to all flights over the UK and to UK aircraft where everthey may be? or something like that.
You can be sure that France has similar requirements in it's law.
As for the high seas!
Regards,
DFC
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OK......but if the slow moving contact resembles the returns that you would, from your experience, consider may be a microlight or light aircraft, you would presumably avoid it - especially if your zone was regularly infringed by such aircraft?
The only way that you can deduce whether an unknown contact may be an aircraft that has infringed the zone is from your primary radar (unless it is squawking and then it is fairly obvious).
What about windfarms which often produce a series of primary returns that are identical to light aircraft? Would you take the chance that it is just the usual returns from a windfarm that you see all the time or would you consider the possibility that it is a light aircraft that has infringed the zone? Mats Pt 1 leaves that decision to you.
One day it will be a light aircraft!
Surely that is one reason for the requirement to have primary radar otherwise we would all be operating SSR only.
The only way that you can deduce whether an unknown contact may be an aircraft that has infringed the zone is from your primary radar (unless it is squawking and then it is fairly obvious).
What about windfarms which often produce a series of primary returns that are identical to light aircraft? Would you take the chance that it is just the usual returns from a windfarm that you see all the time or would you consider the possibility that it is a light aircraft that has infringed the zone? Mats Pt 1 leaves that decision to you.
One day it will be a light aircraft!
Surely that is one reason for the requirement to have primary radar otherwise we would all be operating SSR only.
Isn't the teritorial limits of the ANO put somewhere in there....i.e. it applies to all flights over the UK and to UK aircraft where everthey may be? or something like that.
The UK makes even its Rules of the Air extraterritorial, with an exemption:
84(3) It shall be lawful for the Rules of the Air to be departed from to the extent necessary:
(b) for complying with the law of any country other than the United Kingdom within which the aircraft then is;
On the face of it, it looks like it's exactly what you suggest: that the more restrictive rule might apply. But practically speaking, you have to interpret to the extent necessary quite liberally. It is never necessary to make (or continue) a flight, and thus one can always say that it is never necessary to break any rule from either state.
If I'm cruising on a NEly track outside controlled airspace in France, I'm supposed to be at odd thousand levels according to the UK Rules of the Air, odd + 500 according to the French Rules of the Air. A literal interpretation of 84(3) would simply be that I am unable to fly VFR on that track -- choose IFR instead. (Can't fly IFR? Tough!) In practice, you ignore the UK rule and adopt the local French practice. It would be quite impractical to do otherwise.
I think the same applies where VFR minima are varied. You could argue that a French pilot should reject a VFR clearance with a "not below 1500 ft" restriction into Birmingham class D with cloud at 2000 ft. Never mind that the guy before and the guy after did just that in a G-reg. The only practical option for the French pilot to avoid screwing up UK ATC with an apparently odd request is to ignore the French rule and adopt the local practice.
I believe that that is the way ICAO intends Rules of the Air to be applied. Annex 2 uses slightly but significantly different terminology, and requires that Rules of Air of a state apply to aircraft registered in that state to the extent that they do not conflict with the [local rules].
If every aircraft adopts local Rules of the Air, it provides for consistent behaviour and minimises risk.
(Sorry to have hijacked the thread for a legal debate.)
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siotp:
I guess that would depend on where the windfarm is in relation to your zone bdy and how good your primary cover is around it. If it's comfortably inside the zone and you know your radar's coverage is good in the areas between it and the boundary I'd guess you'd be more likely to disregard any pop-up primary return in the area of the windfarm that hadn't shown up previously.
There are similar problems with, for example, hang gliding, paragliding etc on LoAs inside Class D. You might get fleeting returns from these but how do you know that fleeting return is a hang glider operating under the terms of the LoA, or a zone infringer?
What about windfarms which often produce a series of primary returns that are identical to light aircraft? Would you take the chance that it is just the usual returns from a windfarm that you see all the time or would you consider the possibility that it is a light aircraft that has infringed the zone?
There are similar problems with, for example, hang gliding, paragliding etc on LoAs inside Class D. You might get fleeting returns from these but how do you know that fleeting return is a hang glider operating under the terms of the LoA, or a zone infringer?
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Bookworm,
"You could argue that a French pilot should reject a VFR clearance with a "not below 1500 ft" restriction into Birmingham class D with cloud at 2000 ft. Never mind that the guy before and the guy after did just that in a G-reg. The only practical option for the French pilot to avoid screwing up UK ATC with an apparently odd request is to ignore the French rule and adopt the local practice"
Are you saying that the same pilot faced with a wind out of personal limits should not anoy ATC by holding and requesting info on suitable alternate airfields but should try to land because after all the G reg pilot previously and the following G reg pilot both say there is no problem with the wind and they are flying the same aircraft type?
Are you also saying that certain flights are "screwing up UK ATC" by insisting on IFR clearances in Class D when there is CAVOK weather for 100nm?
As a pilot, I can make the decision that I will require a special VFR clearance every time the vis reported in the zone is less than 8Km..........that is higher than UK requirements however nobody can say that it is unsafe.
No pilot should let peer pressure including pressure from official sources cause them to operate in conditions which are below what is considdered safe.
Isn't your statement that a pilot sticking to international standards that are more restrictive than the UK would be "screwing up UK ATC" doing just that?
Regards,
DFC
"You could argue that a French pilot should reject a VFR clearance with a "not below 1500 ft" restriction into Birmingham class D with cloud at 2000 ft. Never mind that the guy before and the guy after did just that in a G-reg. The only practical option for the French pilot to avoid screwing up UK ATC with an apparently odd request is to ignore the French rule and adopt the local practice"
Are you saying that the same pilot faced with a wind out of personal limits should not anoy ATC by holding and requesting info on suitable alternate airfields but should try to land because after all the G reg pilot previously and the following G reg pilot both say there is no problem with the wind and they are flying the same aircraft type?
Are you also saying that certain flights are "screwing up UK ATC" by insisting on IFR clearances in Class D when there is CAVOK weather for 100nm?
As a pilot, I can make the decision that I will require a special VFR clearance every time the vis reported in the zone is less than 8Km..........that is higher than UK requirements however nobody can say that it is unsafe.
No pilot should let peer pressure including pressure from official sources cause them to operate in conditions which are below what is considdered safe.
Isn't your statement that a pilot sticking to international standards that are more restrictive than the UK would be "screwing up UK ATC" doing just that?
Regards,
DFC
No pilot should let peer pressure including pressure from official sources cause them to operate in conditions which are below what is considdered safe.
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Absolutely, it is peer pressure that forces a pilot to follow international standards of safety!
Peer pressure to do something safe is always good.
Don't forget that a French pilot flying VFR at FL55 on a track of 045 is perfectly legal in the UK!
Regards,
DFC
Peer pressure to do something safe is always good.
Don't forget that a French pilot flying VFR at FL55 on a track of 045 is perfectly legal in the UK!
Regards,
DFC
