Zone Infringements - why ?

[flower]

Apologies if you see this on other forum but the more opinions and information gathered make for a better survey.

NATS has established a working group to look at the increase in zone infringements and is looking at ways to prevent them occurring. This is not about a witch hunt but a genuine attempt at looking at why there has been an increase in zone infringements and a look at seeing what we as ATC can do to help prevent them. I am not a member of the group but have been approached to see if i am happy to work with them or add my comments.

Whilst as an ATCO I may have my thoughts on the matter I would like to throw the question back to the GA flying fraternity for their views on why they happen, ie are the charts sufficient, is Navigation now taught correctly , is their an over reliance on GPS ?
So I would welcome your views and thoughts on how they may be better prevented in the future.

Thank you
Carole

[Chilli Monster]

A lack of adequate planning - which may have its roots early on in a pilots training.

How many schools are under financial pressure to increase throughput, and instructors under the same pressure (only get paid when they fly). Ground exams are more and more being left on a "teach yourself" basis. Now - people may have passed the exam, but be honest. how many learnt the subject, and how many have learnt to pass the exam?

Aviation, Airspace, ATC and Aircraft equipment are organic - always changing. You have to keep up with it all to stand a chance of not falling into the traps that are out there.

There are a few simple solutions. Don't just look at a chart - learn how to READ it (the two are different). When you plot the route fly the trip in your head beforehand - if you see a possible problem at that point think about how it could be averted.

If you have a GPS - LEARN how it ALL works, don't just press the "Direct" button.

If you have a VOR, NDB or DME in the aircraft same again - LEARN how to use it. How many people here have thought how they can fix their position just by using DME in an emergency (go on - think about it - the answer's relatively easy).

In short -people need to think out of the box, not inside the one that your PPL groundschool kept you in.

What is needed in addition is some form of mentoring sytem, where the experienced AND knowledgable (the two don't necessarily go together - believe me!) can talk things through face to face with people and have things demonstrated to them. Forums are great - but they lack that "one to one" that is often required to expand someone's knowledge.

[slim_slag]

Clear more traffic through your airspace. If you have a reputation of telling traffic to remain clear, they will go round the airspace, increasing the chance of a bust.

Provide more radar services so you can proactively manage traffic close to your airspace and make sure pilots know they can get it.

Charts. They are just an OS road map with some aviation stuff overlaid. Cluttered with detail that is of no use, for instance don't need every country lane on a VFR chart. Put only relevant info on charts and should make it easier to visually navigate around airspace.

Airspace. Not designed with VFR traffic in mind. Boundaries of any airspace at an airport with a VOR on or near it should be based upon clearly visible surface features, DME arcs, or VOR radials.

Then I guess some pilots are muppets.

[effortless]

I infringed once but in my defence I was PUT and the instructor was RHS. He knows who he is.

All I can say is that I am crap at navigation. I do not fly enough to get much better but I know it so I tend to be well away from anything that looks like trouble. Charts are crowded and can be complex but then they have to be. I always ask what I should look out for even if it makes me look stupid. I don't mind sounding stupid but in the clear. I do mind looking stupid while cutting up a 737.

I was once on a flip which ended with the newish pilot losing his priviledges for a few years. It taught me a lesson which has stayed with me for thirty years.

Too many of us think we know it all, it is the same on the roads.

[alphaalpha]

Carole:

I thought this subject was researched pretty thoroughly in the 'On Track' project about two years ago. A lot of the conclusions have not really been actioned yet, I believe.

Is there much difference between zone infringements and any other sort of airspace busts?

I think we would do better to try to get the best out of 'On Track' before starting another project.

AA.

[Chilli Monster]

Slim - you may not have realised but it's often pilots that infringe zones - not ATC.

So - with that in mind do you actually have any constructive comments to the question asked?

[slim_slag]

Morning chilli,

I suspect its always pilots, never ATC, but I do believe ATC can make a difference.

Question asked was

"Zone infringements - why?" "So I would welcome your views and thoughts on how they may be better prevented in the future. "

I have presented my views and thoughts. I would welcome your constructive thoughts on what I have said.

[Charlie Zulu]

If it were posssible for more traffic to be cleared through the airspace in which flower controls then that traffic would be cleared through. For every occurence of a zone clearance being refused by the controller, for whatever reason, a mandatory form has to be filled in... (I think I am correct in saying this).

Yes I agree with providing more radar services. In fact I would go as far to say that if they could provide something along the lines of "Flight Following" that the American's have then we would be so much happier... Flight Following is just one of those fantastic services that is available free of charge to the GA pilot stateside.

I'm in full agreement with the charts. Too much clutter. Especially airspace above 10,000'. They could probably do something like they do with the quarter mils and only have airspace up to 5,000' (or FL55) depicted BUT increase the height to something like 10,000'. That would incorporate most, if not all, VFR flights...

For instance I showed the Southern UK chart to someone in LA (for anyone who hasn't seen the LA chart then its ever so slightly more complicated looking than London). The first thing they said was, "How the **** do you fly VFR around that area?" whilst pointing to London.

But it also comes down to initial pilot training, just as Chilli Monster suggests...

Personally I would love to see a proper oral type examination introduced before each and every checkride. This ensures one learns the subject material in depth... just look stateside (yes I know I keep referring to FAA land but they do have some things right). Okay their written test is a little bit of a joke but then again our own written tests (I am talking about the PPL *not* ATPL) can be passed by "learning" the confuser. With an in depth oral exam before the skills test (just like the FAA way of things) then that would ensure candidates studied the subject material fully and actually "understand" the subject material.

[Chilli Monster]

Clear more traffic through your airspace. If you have a reputation of telling traffic to remain clear, they will go round the airspace, increasing the chance of a bust.

Not always possible. It's therefore a good idea for the pilot to plan an alternative route in case that happens (read my answer re: "head flying" at the start of this thread)

Provide more radar services so you can proactively manage traffic close to your airspace and make sure pilots know they can get it.

Nice idea - and you'd fund it with.................what? (or should that be by who? A very thorny subject indeed). I shan't even mention how you would staff it (30% shortfall in ATCO's Europewide I believe).

Charts. They are just an OS road map with some aviation stuff overlaid. Cluttered with detail that is of no use, for instance don't need every country lane on a VFR chart. Put only relevant info on charts and should make it easier to visually navigate around airspace.

Don't know what you're using. But the standard ICAO 1:500,000 chart doesn't come anywhere near what you're describing

Airspace. Not designed with VFR traffic in mind. Boundaries of any airspace at an airport with a VOR on or near it should be based upon clearly visible surface features, DME arcs, or VOR radials.

Why should it be? Controlled Airspace (which is what you are referring to) is designed for the protection of IFR traffic inbound and outbound IFR and as such is designed with that purpose in mind. Yes, in an ideal world it would follow the U.S model of being based on an "on airport" VOR/DME facility but with the lack of such a facility on many european airfield that's hardly a possibility. With the gradual retirement of ground based aids in the next 20-30 years it's not exactly sensible (or sound fiscal planning) to start basing airspace construction on facilities whose years are numbered.

[effortless]

So does anyone know how the infringers are broken down? Are they mostly experienced in transit? Inexperienced who haven't the foggiest? Fat git like me out for bimble who hasn't noticed the cross wind? I'd be interested but I know that my definitions aren't helpful.

[flower]

However controversial keep the opinions coming, as i said this is not a witch hunt and it is not about blame but about how we can help prevent them.

[slim_slag]

Ok chilli, so the money and resources aren't there for my first two thoughts. That's fine, but at least we have addressed the issue and it won't be an unanswered question.

How about Class e/f/g corridors? Works elsewhere.

Charts. I was referring to 1:250,000. If you look at the OnTrack charts they have removed a huge amount of unnecessary clutter, the problem is they are not legal for navigation. They are a definitely a vast improvement over the standard chart, and er, designed to help prevent zone infringements.

Controlled airspace can be designed with vfr pilots in mind. So, for instance, if there is a readily available surface feature (road/river/coastline) just outside the calculated boundaries of the protected airspace, extend the boundary to that feature. No reason any future airspace changes/grabs shouldn't use the same principle wrt navigation beacons, or GPS waypoints.

Found a good example. The southern boundary of the Heathrow surface area could so easily be defined using a radial off the BIG VOR, but it isn't. Why not? Why isn't the eastern arc of the surface area a DME arc off the london vor? TYou could use the M25 as the northern edge of part of the Gatwick 1500ft area. So easy to do, nobody thought VFR when doing airspace.

[tacpot]

I'd hope most pilots plan their (horizontal) routes with some reference to their experience levels and the equipment fit in their aircraft. IF inexperienced an only using a compass, perhaps it might be batter to leave a wider margin around controlled airspace than if experienced and able to use GPS/Radio Navigation.

But it's my experience that vertical navigation is not taught well at the PPL level, and indeed I still struggle with a conventional PLOG finding the space to indicate level changes when these are need to avoid controlled airspace. I've tried with map annotations (in increasing amounts of red INK) but this still doesn't leave me feeling that I definitely won't bust controlled airspace. I'm still in search of a better PLOG format for vertical navigation...

Does anyone use VORs to setup a "do not cross" line on their chart, as a way of making sure you are clear of controlled airspace?

tp

[dublinpilot]

Flower,

Purely out of curiosity, what would the breakdown, in your zone, be between


A) Busts that largely track the edge of the zone (indicating someone thinking they are tracking outside the zone), and

B) Busts that go straight through a large part of the zone (indicating someone who was totally unaware of either the zone, or their own position.) ?

Just curious.

dp

[IO540]

One can assume CAS busts are caused by nav errors, or by map reading errors.

I find the latter incredible because IMHO the CAA 1:500k VFR charts are by far the clearest of

Jepp VFR/GPS (lousy choice of colours, occassional ambiguity)
French SIA (poor terrain info)
Swiss ICAO (stupid mixture of ft and m in elevations)
FAA sectionals (one needs to know the implied airspace types)

Only the French 1:500k IGN charts compare for clarity with CAA but they omit stuff above 5500ft, making them IMO useless for serious flying.

The CAA charts are exemplary for clarity and lack of ambiguity. A pilot from Mars could use them right away. Helped by the fact that one really can just about "fly anywhere" in the UK; Class G is plentiful and there is no French-style military airspace all over the place.

So, what causes nav errors? Candidates must include:

1. Lack of currency: Present-day GA scene is too decrepit and so attracts too few people with funding adequate for flying. So, most PPLs fly too little, 10-20hrs/year?

2. Peer pressure to use old fashioned methods: Too many old farts in GA telling everyone that stopwatch+compass is the only real way to do it. This was fine 50 years ago when there was little CAS to bust, and is OK for a pilot who has been flying around the UK for past 30 years - even if he flies very little nowadays. It's not OK for a recent low-currency PPL.

3. Poorly equipped aircraft: most planes flying are old rental spamcans in which very little works. Obviously this argument is on a hiding to nothing if you believe in the old fashioned methods but it also scuppers any attempt to modernise.

It's tempting to blame the often poor training but I can't see how anything else (a full inclusion of GPS in the PPL being the obvious thing to do) can be included without increasing the minimum hours from 45, and few people want that. It would also necessitate mandating panel mounted GPS installation in training aircraft, which the industry would really hate.

Instrument-capable pilots routinely navigate GPS/VOR/ADF/DME when when flying VFR but IMHO it would not be productive to get PPLs to use VOR/DME routinely because, at the very low levels enjoyed by many pilots, one cannot receive the navaids over much of the UK.

A full inclusion of GPS is the way to go, but it will never happen.

[Fuji Abound]

1. Pilots should be trained to use a moving map GPS,

2. The aircraft should be fitted with a good quality moving map and the database updated when necessary,

3. Infringements would very rarely occur.

:D

[WorkingHard]

"I would like to throw the question back to the GA flying fraternity for their views on why they happen" - This seems to pre-suppose that it is GA who are the only culprits. this is not the case as we all know. My view is that navigation in the UK is extremely difficult because of weather and CAS boundaries as described earlier. I am not suggesting there is any easy answer but we clearly need a sort of continuing "on track" operation the recognises the obstacles in the way of VFR navigators.

[hingey]

Never had a zone bust, but the times I have come close were due to wind calculation errors or different wind to what I had planned for altogether. The relevant controller advised that my heading took me into their airspace so I diverted. If an ATCO sees somebody bumbling towards their CAS, they should shout. Obviously, this is no good without the pilot being tuned in. Never forget the 6 P's! If your flying close to CTA, call them on the radio. If your not intending to go close to the zone, at least have their frequency on standby. Tune in and ask if you think you might be a little closer than planned. IMHO, pilot awareness and planning are the key factors in zone busts.

With regards to GPS training, what about a couple optional hours on top of a PPL, like with a night rating? GPS may replace older forms of navigation, in which case the methods they replace will be taken off the syllabus, keeping it at 45 hours. Of course costs probably would go up, whatever happens, but a required rating to use a GPS would reduce the number of GPS blunders.

Though having said that I haven't gone electric yet, and so far have done fine without. Some people are just idiots (no offence anybody :ok: )

h

[slim_slag]

So IO540,

You tell us that

"The CAA charts are exemplary for clarity and lack of ambiguity. A pilot from Mars could use them right away."

yet you have to use a moving map gps to avoid busting airspace, and you want to make us lot use one too ! :) You aren't going to force that one on me.

One thing is for sure, a Martian wanting to learn how to design airspace wouldn't spend long fact finding in the UK. :ok:

[HelenD]

The times I have been closest to infringing a zone are when I have been routing back to my base airfield that is within the zone but ATC is too busy with people giving their life stories informing them about their latest problem with their Dash 8 indicating they will miss their takeoff slot or worst of all asking for the latest results of a major sporting event and I cannot get my request to enter the zone in. The few times I thought I would call up early and speak to the approach controllers rather than tower I get told to use a different airield instead. If you are concentrating on trying to get a call in you may not notice that you are getting very close to the zone. I have noticed that you do appear to get a better service if you ask for an IFR rejoin in preference to a VFR one.
One other thing to bear in mind with PPL traffic is we are usually single pilot ops and do not have the luxury except on training flights of the First Officer/ Captain doing the radio while we or the autopilot do the flying.

[flower]

This is about GA infringements hence why I am asking the GA fraternity for any responses.

WR, yes we have zone infringer's at Cardiff, not to the same extent as many others but that is potentially because if we see an aircraft about to infringe we tell them either to adjust their heading or give a clearance through.

This is not about specific zones but about looking at why they may occur , I have had through the various forums some well observed comments, thank you to those taking the time.

[Pierre Argh]

if there is a readily available surface feature (road/river/coastline) just outside the calculated boundaries of the protected airspace, extend the boundary to that feature The way it should works is, when planning your flight you look for such features outside of CAS, then use them to ensure you remain clear. Far easier than describing the zone boundary as a wavering line (following the River Piddle) to an IFR pilot who cannot see the ground.

Furthermore CAS is designed (believe it or not) to be the minimum possible/acceptable size... start stretching it to a convenient VOR radial, or so it follows the M25 and you'll lose a sizeable chunk of Class G across the whole country.

Like Chilli says, there isn't enough money in the kitty to fund LARS as it stands, who out there thinks it'd be a good idea if ATC charged for LARS?

[IO540]

slim_slag

There is a distinction to be made between

a) having problems reading a chart, and

b) navigation

It has been suggested by some that a) is responsible for some infringements, hence my comment that CAA charts are clear enough.

[Droopystop]

Planning and practice.

I have never had a problem using CAA charts. I choose not to use half mils, but that is a matter of personal choice and it suits the flying I do. Quarter mils are great because there is generally some feature that you can pick up during planning that you can use to avoid the zone. Peculiarly shaped bits of forest, lake, town - draw a black line around it to highlight it on the chart and know where you have to be relative to it to stay clear. Simple. Just as a matter of interest, how are fixed wing pilots taught to navigate? Is it literally just compass and stop watch or do you feature hop?

Or buy a decent GPS and learn how to use it before you take it flying. But wait a minute (and I apologise IO540 if this has been thought of before) has anyone bothered to check that a) GPS charts are coincident with the CAA charts or b) are the overlays used on the radar in the right place? Stupid I know, but has anyone thought to check it?

[IO540]

A moving map GPS is largely self-checking.

You switch it on; within a minute or two it captures enough satellites to do a fix, and the map centres on your position. My preflight check includes a) zooming right in and checking that the position shown (sitting on some place on the airport) is correct and b) the GPS altitude is within say 50ft of actual.

Then I set it to something like 20nm full-scale and fly off.

Accuracy of the database datum isn't an issue; that's all done for you.

After loading a route, the route is displayed on the map and one checks it for gross errors; one may have to zoom out to say 1000nm full-scale to see the whole of a 700nm route, obviously.

Can't speak for radar calibration but imagine they do it by flying a plane with a GPS (and a DME) in it around the boundary :O

Regarding radar, I've occassionally been accused of infringing when I knew I wasn't (GPS and DME), but could see that the controller was concerned about the *projected* radar track which would infringe if I stayed on it. I got this once from Lyneham; phoned them afterwards and they admitted they do this to "VFR pilots" who often infringe in droves :O

[WorkingHard]

Flower - I did not understand from your first post here that it related only to GA CAS infringements, so my post was off track. May I ask if the NATS working group you describe is similarly charged with looking at GA only? Is there any group looking at other CAS busts?

[slim_slag]

Pierre, of course I will not be able to see the river if I am above clouds. But it will also invalidate the navigation method you intend to replace mine with, you will pick a visual feature outside the CAS, mine will be the boundary.

How many GA people fly VFR above clouds in the UK? Perhaps the vast majority who don't fly above clounds will be helped by making the boundary follow surface features, and we are after all only giving suggestions.

Your method of following a feature outside CAS will, for all practical purposes, reduce the amount of class G as putting the boundary on the river. So no difference from me there either.

I have no idea how they calculate the boundaries of CAS, but looking at the southern england chart, there appears to be a lot of it places I would not expect it. It has most certainly not been designed with VFR traffic in mind, and the designers should therefore share some of the blame (only a little) for zone infringements.

Far easier than describing the zone boundary as a wavering line (following the River Piddle) to an IFR pilot who cannot see the ground.

How would you describe the boundaries of the gatwick surface zone to an IFR pilot, if he had any interest in knowing?

[Droopystop]

IO540,

I am sure that the GPs is sufficiently accurate and all the automatic checking is done for you but.....
Accuracy of the database datum isn't an issue; that's all done for you.

By who? By using what method?

What I am trying to say is has anyone checked that when you are flying "hard up" against a zone boundary as displayed on the moving map, you are not the wrong side of the line on a radar screen. Someone might have had a bad day at Jepps writing in the airpsace data? Or is it that the positional accuracy of the radar is no longer as good as GPS.

Or have we another scenario where ATC anticipates a likely infingement, ie if current heading is maintained, but the aircraft turns away at the last moment - does that count as an infringement? Especially if there is no radio contact. May be the problem is that there is a difference of interpretation?

Flower,

The bottom line here is that there is a whole heap of issues here and your posts are very open. What sort of infringements are we talking about? Perpendicular zone penetrations deep into CAS, or are we talking "glancing blows"? Have NATS stopped to think that it might have something to do with them? For instance are radars accurate enough to pick up which side of the line a contact is? Moreover is there is a difference between what a pilot would consider an infringement and what ATC would report?

IMHO if you want some constructive input from the GA community, you are going to have to be a bit more expansive on the issue.
Here is a few points for starters....
- What is the ATC definition of infringement.
- What are the statistics
- How many infringements involve a penetration of less than 1 or 0.5 nm
- What investigation has NATS already done.
- Is one area more prone than others.
- Have NATS checked that all e charts, paper charts etc are the same?

I am not trying to critise what NATS do by any means, or trying to belittle what Flower is trying to achieve (I think the effort is admirable). Just more information please!

[High Wing Drifter]

The CAA charts are exemplary for clarity and lack of ambiguity.
I tend to agree. However, I think there is a definate skill to using the charts that only seems to be refined with experience, possibly not ideal for low houred chaps. In many ways this boils down to simply knowing what the multitude of possible features are likely to look like from the air.

I noticed during my night qual, many moons ago, that all the red stuff on the chart is rendered invisible with a red torch/dome light at night. Maybe another colour is in order. Never mind the roads being handy for navigation, but the airways are an obvious potential problem.

[flower]

This is purely an exercise on my part and not that of the working groups. I am not part of that group but have been asked for my input from them. I wanted a Vox Pop I suppose of how you view infringements and why they may happen. It is nothing more than that. I shall be submitting a report but this post itself is not in anyway official and should not be considered as such.
Should the working group decide to open up this subject to the GA fraternity it will come with terms of reference and go through the appropriate channels.
There are some extremely interesting views and thank you for them.

[IO540]

Droopystop

You make a valid theoretical point but when working at this level one has to trust somebody! Jeppesen do have errors in their data but much of the commercial world uses their approach plates, in either printed or electronic format, their data gets loaded into FMS systems, every aviation IFR GPS uses it, and this wide usage means that if a major error crept in (which has happened) it gets picked up and fixed fast.

Even the CAA charts have errors; they have huge masts missing for example.

And electronic data is much more likely to be correct, at any randomly chosen point in time, than paper charts that get "fixed" some months before going to print and then they are in all the shops for the next 12 months.

I have seen massive errors in CAS depiction in printed charts in France (IGN, Jepp were seriously wrong, SIA were OK) and these would have persisted for up to a year, whereas in electronic data they got corrected within the 28-day cycle.

You probably also refer to a general issue of map accuracy. The way this is done depends on whether the database is described as objects (each with lat/long data attached to it) or whether it is a bitmap. In the former case the calibration is taken care of implicitly, and will be right provided the database is right. In the latter case one has to calibrate the bitmap by marking several points on it and entering the coordinates for them; however this is rare in aviation units because nearly all use the Jepp vector data, not bitmaps (the Memory Map PDA-based product is one exception).

If you want to know about bitmap calibration, look up www.oziexplorer.com. It takes me only minutes to calibrate a scan of an entire country map, to within a fraction of a mile all over. In fact the surveying itself it likely to be far worse than that!

In all cases, one obviously assumes the GPS receiver is returning the correct position but there are so few players in this market this isn't normally a problem. The SIRF chipset is known to return GPS altitude 200ft too high, but one soon spots that!

A properly designed GPS is supposed to detect when the fix isn't good enough (or is entirely lost) and it displays a "NO SATELLITE RECEPTION" or similar message. Anecdotal evidence suggests the really old units (e.g. the Garmin 195, now over 10 years old) have bugs which cause a loss of fix without the warning appearing.

"Or have we another scenario where ATC anticipates a likely infingement, ie if current heading is maintained, but the aircraft turns away at the last moment - does that count as an infringement"

NO, but they might pretend to the pilot otherwise. It certainly makes them nervous.

Flower

I suggest someone correlates infringements with GPS usage, types of equipment, pilot currency with it. Without this, you will never get anywhere. Human IQ has hardly changed in the last 50,000 years, PPL training will never get any better (and will get worse as GA activity slowly reduces) so modernisation is the only way.

[Pierre Argh]

IMHO IOS40 makes a valid point about increase in GPS use... The kit is fantastic, but like all hardware only as good as the liveware input. Yes it'll tell you how to fly from A - B in a straightline, and keep you advised how many feet left/right/above track you stray... but I feel that leads pilots to think its OK to skirt too close to the boundaries of Zones.

There is no definition of an infringement (too obvious to bother I would have thought) and I can certainly recall arguements with pilots over the radio as to whether they'd infirnged a zone or not... one actually stating he was 0.1nm clear.

The fact is as a controller I use a radar, that probably doesn't display to that level of accuracy, to separate aircraft. That's my concern, not whether an aircraft is in or out of the zone... so the decimal places don't mean much to me other than whether I can control YOU or not? Actually, when cross-checked with a precision source the stroppy pilot who claimed he was clear of the zone was actually 0.25nms inside it... because he had misinterpretted the zone origin... back to my original point, would he have considered going that close without GPS... I doubt it?

[IO540]

"would he have considered going that close without GPS"

Probably not; in fact he would probably have stayed on the ground, or did a (very) local burger run instead. Soon he would have got fed up with that sort of relatively pointless flying, and left aviation for good.

That's one innovative solution to CAS busts - reduce the number of people flying!

Or force people to stick to useless local flights only, where they know e.g. the M25 just happens to mark the CAS boundary.

The job here is to deliver a more reliable navigation solution. As I say, no use looking at training or "pilot quality"; those will never get better.

[DFC]

If one reads many of the posts here, one can pick up a general trend that I believe can be the cause of many infringements. That being that in general pilots who have to go round some airspace want to get as close as possible to the boundary and thus minimise the track distances involved.

The CAA recomend that pilots try to miss zone boundaries by 5nm laterally (the 5nm allowing for navigation errors). Even on a 90 deg turn this would only add a few miles to the track and less than 5 minutes to the total time.

GPS users must be aware that even approved IFR panel mounted units are RNP5 - they only keep you within 5nm of track. So why use a handheld to try and stay within 1nm or less of track.

Another reason for infringements of various airspace is the use of QFE and RPS and giving VFR enroute flights the option to use Altitudes above the Transition Altitude.

On a related point, if somewhere like Lyneham Radar observes a slow moving primary track cross their zone West to East, do they report an infringement or do they assume that the primary return is above their zone?

Regards,

DFC

[IO540]

even approved IFR panel mounted units are RNP5 - they only keep you within 5nm of track

If taken literally as stated, that's rubbish.

I hope you are not a pilot, DFC.

[WorkingHard]

My flight yesterday took me close to 2 areas of CAS and the weather was cr**, or should I say very poor. My navigation is usually very good and as I use VOR, NDB, DME all crossed checked with GPS I can usually be pretty sure where I am. Now the point is one controller gave me a RIS which helped enormously for the odd bit of weather avoidance and he was happy that he knew who I was and where I was and if required could enter his zone at a predertmined level.
The other just gave the usual response of "stand by and remain clear etc." Now I have no problem with the second but it would perhaps have been more helpful to both sides if he could have found the time to just check what I was expecting (I do not know how busy he was of course since I could only hear the frequency on which I called ) and then advise. He would have at least been equipped with the knowledge that I was UNDER his CAS and he needed to do nothing about me. Perhaps may have even alleviated a possible "infringement" report. Earlier someone asked about the traffic that goes under or over CAS. If you are a controller not working them do you automatically assume (if no height read out available) they are clear?

[JustaFew]

Perhaps it might help if the word FLOWER is written around the relavent CTZ boundary...

[DFC]

CAA Occurrence 200505672

BE90 King Air. Alleged infringement of the London CTR.

The pilot believed that he had navigated around the CTR. Three days after this incident the route was reflown with an ATC staff member on board. On this occasion, the aircraft also established communication with London SVFR as a safeguard. The primary navigation tool was a GPS. The aircraft tracked west until it reached the eastern extremity of the Wycombe ATZ before turning onto a track of 190 degrees. This should have kept the aircraft clear of the Heathrow CTR. However it became evident from observation on radar that this turn was taking the aircraft into the CTR. Analysis has shown that the software used on the GPS had not illustrated the London CTR accurately and had also shown the Wycombe ATZ as having a wider radius than it actually has. Thus when the aircraft commenced the turn at the Wycombe ATZ as indicated on the GPS it was turning too early and infringing the CTR. The pilot will now use alternative navigation strategies when tracking around the Heathrow CTR.

The above example comprises all of what I believe are the common causes of infringements - 1. Trying to cut it too fine round the edge, 2. Over reliance on GPS, and 3. A patchy ATS.

---------

IO540,

Read the above again. I know that you are sure it won't happen to you and that is fine! The rest of us will just stick to padding the safety margins! :)

Regards,

DFC

[IO540]

"Analysis has shown that the software used on the GPS had not illustrated the London CTR accurately and had also shown the Wycombe ATZ as having a wider radius than it actually has. "

If you could provide the make, model, database of the GPS that might be useful, to somebody perhaps.

But what does a database error have to do with your alleged GPS-inherent error of up to 5nm?

You are wasting your time, DFC, totally and completely. Because for every GPS database error you can dig up (and I can dig up one or two myself, from bits of Europe too remote to bother most UK PPLs) anybody in ATC can dig up THOUSANDS of infringements caused by IGNORANCE of modern navigation methods (known as "good airmanship" by the old farts).

Touch wood, I have never been lost, even for a moment, and the only time I have infringed CAS was when climbing/descending when I just clipped the three-dimensional corner of where it changes level. I've done that quite a few times.

(I've busted a certain foreign TRA, which in those days didn't show up on Notam.)

But every time I fly some distance I hear a number of pilots who are clearly lost. It's good luck that there is a lot of Class G around. They usually sounds well overloaded so one must assume they are exercising proper airmanship.

"The pilot will now use alternative navigation strategies when tracking around the Heathrow CTR."

Well he had to say that, in his grovelling letter to Captain Somebody (Ret'd) at the CAA; the one with the really posh fountain pen with a 1.5mm wide nib, whose job is to write stroppy letters to people who the CAA doesn't prosecute. Still, it's a lot better to grovel than to get done, especially if a certain foreign CAA is involved.

Tell me, DFC, what "navigation strategies" would a King Air be using instead? I can just see the ATP (likely 2x) going to Transair to buy a stopwatch, a CRAP-1 slide rule... I suppose he could have flown a DME arc (autopilot coupled) all the way round :O

[benhurr]

All this talk of GPS.

Is it part of the PPL course? No.

Is it part of the CPL course? Yes - but only frequencies, RAIM etc.

Maybe if the syllabus recognised modern navigation aids then there might be less zone busts.

GPS position errors are now potentially within a few feet - possibly this is more accurate than radar.

My suggestion - teach people to use the huge advantages of GPS proactively - incorporate it into the PPL syllabus.

Around Stanstead (cos you are never ever ever going to get a FIS) it is fun to fly just outside the zone and not talk to them.

How about a VFR GPS VRP database (I love acronyms). That would probably reduce zone busts by 50%. Then include GPS navigation in the PPL training - that would probably reduce zone busts by another 49.9%

Of all the people viewing this thread who has had proper training regarding the use of GPS? Maybe a poll is in order.


Flame away

[PPRuNe Radar]

IO540

Ok, regardless of the thrust of DFC's argument .. what do you understand by RNP and what RNP do you think your GPS is certified to ??

[englishal]

GPS is GPS, who cares what it is certified for for VFR flying, its more accurate than anything else out there.

5nm error....never (without you knowing about it). I have used GPS since 1995 to position equipment for the oil industry and have never had more than a few second nav jump. Accuracy is now within metres even on my cheapo eTrex sub £100 unit. Try this with an NDB.....

dB errors....possibly. Thats why I would create GPS waypoint on the centre of the zone, and ensure my GPS DME never drops below 5 miles or whatever, or download "official" waypoints.

[IO540]

RNP5, AIUI, refers to nav capability. It doesn't have any relationship to the actual equipment. Meeting RNP5 just means the device meets RNP5. It says nothing about the device itself, and most importantly, it does not imply that the device will only just meet it.

GPS is either working (and accurate to a few metres 99% of the time, and a few more the rest of the time) or it isn't (no reception, device has failed, etc).

I would bet that RNP5 goes back to inertial derived navigation, where an error of a mile or two is entirely plausible. INS uses DME/DME to keep itself reasonably accurate but often it won't have DME reception (e.g. over large swathes of France).

KNS80 and similar old RNAV solutions (VOR shifting) also comes to mind as likely applicable to this.

[Kolibear]

The CAA recomend that pilots try to miss zone boundaries by 5nm laterally (the 5nm allowing for navigation errors).

Which would close the gaps between Heathrow & Luton, Luton & Stansted; Heathrow & Gatwick.

even approved IFR panel mounted units are RNP5 - they only keep you within 5nm of track

The GPS doesn't keep you on track, it only displays the route to follow.

Its up to the pilot to follow the route displayed.

[Droopystop]

Flower,

Here is my interpretation of what seems to be happening in the GA environment.

Infringements happen because they are flying too close to zone boundaries, either deliberately or because they are lost. I would therefore summise that a proportion of infringements are pilots who are lost. Others will be those who are cutting the margins to the limits on their whiz bang nav sets who genuinely believe they are clear of the zone. Case 1 is a serious problem and needs addressing. Case 2 is less of an issue since the pilot knows where he/she is and acknowledges the existance of a zone, but is just the wrong side of the line by a small amount.

IO540

The King Air incident was repeatable and as you say GPS's are not inherently inaccurate, so the make and model of the set is largely academic. Therefore it must be the database that was incorrect. The question is which database? The database that the controller's radar uses to overlay the zone boundary or the GPS data base? It is the answer to that question that I would like the answer to.

Unfortunately I do not have a moving map GPS, but here is a challenge for someone who does. Take the SW corner of the London TMA where the King Air infringement happened. Find its lat and long in the AIP and load that position into the GPS as a way point. Then see where it is relevant to the moving map's location of the zone boundary. Perhaps that will answer my question.

Here's another thing. How many pilots check that their GPS set is using the same survey datum as the CAA charts? I am sure that those who know about it do, but does the average spam can hirer?

[BEagle]

I use GPS to tell me roughly where it thinks I am - and a CAA 1/2 mill chart to confirm that. I do not think that reliance on a basic GPS moving map will ever be safe unless the software is regularly corrected. None of my a/c GPS systems has a moving map and we do NOT update the waypoint database - this then forces pilots to use it as a back up to traditional VFR navigation on pre-planned tracks between specified points using the CDI scale with +/- 1.25 mile fsd sensitivity. The edge of a CTR may change, but lat/long never will!

But I wholeheartedly agree that it would be nice if a good ground feature could be used as a delineating feature whenever possible. Years ago I did low level local air defence in the F4; up to the stop line we would chase any hostiles, beyond that the Bloodhounds would take them out. It was dead easy (and quite wise) to knock off any attack before infringing the Bloodhound engagement zone as the boundary was well defined by the main A14 Ipswich-Stowmarket road.

[IO540]

Beagle

If the RAF still navigates this way, it is as well it is the Americans who get to do the dirty (but usually necessary) work around the world today!

Recently I spoke to a Hawk pilot (an instructor as it happens, too). He said they navigate absolutely using dead reckoning, map, stopwatch. GPS is out of the question. I asked him what would be the function of a Hawk in a real conflict. A long pause followed........ the enemy would only need to wait for some clouds to form :O

Droopystop

The SW corner of the 2500ft+ TMA is, measured from the displayed map

Jepp Flitemap (current Jepp vector database)
N 50 58 31
W 000 34 28

Jepp Flitemap (current Jepp "VFR raster charts" database)
N 50 58 31
W 000 34 23

Navbox Pro (current Navbox database)
N 50 58 20
W 000 33 40

Memory Map (2004 CAA 1:500k chart)
N 50 58 29
W 000 34 25

Memory Map (2004 CAA 1:250k chart)
N 50 58 31
W 000 34 27

OziExplorer (real 2004 CAA 1:500k printed chart, scanned, my own map calibration)
N 50 58 32
W 000 34 23

All the above are within the thickness of a line on the printed chart.

Perhaps someone with more time will look up the official lat/long in the AIP but frankly I doubt ALL the above products are wrong! I also know the last one above was no more "wrong" than the printed CAA chart itself because one can overlay the chart grid onto the map display and see if the two grids line up.

So I wonder just what "database" the King Air was using.

How many more GPS navigation products do you want me to dig out? I have an old Skymap 2. I also have a KLN94 and KMD550. But these all use the Jepp vector database.

There was a stand-up comic on TV who used to always start with "I am going to tell you a story...." (Frankie Howerd)? I can tell you a story about a VOR receiver which would show a perfectly plausible radial, no flags showing, but it was complete rubbish. I also used to fly an Archer whose DME would show anything it felt like, but most of the time it mattered (say on an NDB/DME approach) it was usually plausible, but it was rubbish. Now, that is really dangerous because all multi-step step-down approaches are that way for terrain clearance. So, let's ban VOR and DME navigation.

As a general comment, I doubt whether more than 1% of UK PPLs read this stuff. However, the pro-GPS and anti-GPS pro-modern anti-modern conflict pervades GA very thoroughly everywhere (except among pilots who go places and who can't be bothered to argue about nonsense like this). It does not suprise me, given the wide range of types of aircraft operated, and the huge range of pilot ages. What does suprise me is the way the GA Dept of the CAA remains on the sidelines, letting it carry on. All the while approving BRNAV units, which makes a mockery of the attitudes of its (very small) GA Dept.

[Droopystop]

Thanks IO, I'll check the AIP this pm.

So where does the Radar think the boundary is?

It seems mighty strange to me that using GPS is causing an increase in infringements if the database and the sets are as accurate as they claim to be.

[High Wing Drifter]

Recently I spoke to a Hawk pilot (an instructor as it happens, too). He said they navigate absolutely using dead reckoning, map, stopwatch. GPS is out of the question.
There almost certainly won't be a reliable GPS signal anywhere near the enemy; the GPS system is very easy to jam.

Two points, first I'm pretty sure they would use a combination of GPS and INS/IRS, second at the sort of speeds the RAF would do inbound, the difference between a 10kt and 40kts is probably somewhere in the region of only 2degs of drift, so deadreckoning would probably in many cases be a viable option!!

[IO540]

the GPS system is very easy to jam

Not the military signal, with military receiver technology coupled with FOG gyros.

If one has FOG input, one can tighten up the GPS PLL to such a degree that the jammer needs about 30db (1000x) more jamming power, than is needed to jam a plain civilian GPS.

[IO540]

OK 2 more bits of data

Skyforce / Honeywell Skymap 2 (2004 Jepp vector database)
N 50 58 50
W 000 34 50

Skyforce / Honeywell KMD550 MFD (May 2005 Jepp vector database)
N 50 58 53
W 000 34 45

So far, everything lies virtually on top of each other, so I consider the King Air matter a bit of a wind-up.

[englishal]

I remember Irv Lee (I think) of Flyer did an airticle a few years back where he skirted Bournemouths Zone using MM gps and then compared the results with the radar data. From what I remember it seemed pretty accurate.

[IO540]

Well it would be. GPS, if its working, is accurate to well within the thickness of the line on the CAA chart.

[Fuji Abound]

I agree with IO540 on this - as I said in my earlier post the simplest and most foolproof way of stopping zone infringements is by training pilots to use and equipping aircraft with moving map GPSs.

I know some will go on putting forward the age old arguments about reliability but there seems so little evidence to support these arguments. In fact there never really seems to be any evidence at all.

Consider the facts. In my experience I have never lost the GPS signal (not a single time) and I have never found my position to be any where other than that shown on the moving map. I have also never had the GPS unit fail (although I fly with two and have a third in my bag!). In the same time the VOR has failed twice and the DME once. Moreover the moving map tells you exactly what you should expect to see on the ground. Personally I would expect you to compare the ground information with the map occasionally - it really is not that hard - and there is no better fail safe.

There is a whole debate about skirting very close to CAS. However you see that debate, it cannot but help to tell the controller that you intend to skirt his CAS closely. In so doing he does know you know where you are and if he thinks you are beginning to invade his territory is likely to tell you before it becomes a problem. Whilst I don’t know the precise circumstances of the King Air bust once again had the controller known their intention to skirt CAS closely I would expect they might have warned of the infringement.

We should not forget CAS is like a prison wall keeping not only us out (without permission) but also the rest in. Whilst it is not the controllers implicit responsibility to keep us they don’t want the hassle of zone infringements any more than we (on the whole).

[High Wing Drifter]

Fuji,
Consider the facts... and I have never found my position to be any where other than that shown on the moving map.
I have :uhoh:

[Fuji Abound]

High Wing Drifter

How much was the map adrift by?

Why was it adrift?

How many times has it occurred?

How quickly did you identify the problem?

With respect, that was my point. Pilots say GPS is not very reliable, but never seem to set out the facts.

[DFC]

Touch wood, I have never been lost, even for a moment, and the only time I have infringed CAS was when climbing/descending when I just clipped the three-dimensional corner of where it changes level. I've done that quite a few times.

Intentionally infringing controlled airspace was not something that I expected to be entered into the debate! Do many pilots simply "clip the corner" of a CTA without being lost?

----

With regard to the Heathrow zone case, looking at the CAA chart there is only about 2nm bewteen the Wycombe ATZ and the London CTR. Not much room for error there no matter what method of navigation is used. The gap between Wycombe and the Benson zones is much bigger and often with a radar service available from Benson. Perhaps taking a wider route (3 minute delay) and obtaining a radar service is a better strategy! Definitely better than trying to visually shoot a 2nm gap in busy low level trafic with the view available from a King Air Office!

-----
How about a VFR GPS VRP database (I love acronyms). That would probably reduce zone busts by 50%

How about everyone using the one provided by the CAA on its website!

------

Kolibear,

You are correct. makes no diference how accurate the equipment if people can't make use of such accuracy. Most people with some training can keep a CDI centered or the aircraft exactly on the GPS derived track line - provided they watch it most of the time. What happens to lookout in those cases?

------

BEagle,

Insted of expanding a zone to a line feature currently some 3 or 4nm outside the boundary, why not teach pilots that it would be a good idea to use that feature as a "handrail" to avoid the airspace. i.e. track crawl when there is a good reason for it?

-------

It does seem odd that ATC must try and keep flights 2nm minimum inside the boundary but every puddle jumper on the other side of the fence wants to get as close as possible. Perhaps we have to ask why this mindset is common? Perhaps in that culture of taking it as close as possible is the answer?

Regards,

DFC

[englishal]

Well it would be. GPS, if its working, is accurate to well within the thickness of the line on the CAA chart.
I meant that the database tied up with the radar data, as well as the fix being accurate.

I use memory map and CAA digital charts, and they are so accurate you can use them to see which taxyway (and which side of it) you are on.

People keep mentioning the CAA dB. I searched for ages yesterday trying to find it, could someone post the link here please?

ta

[WorkingHard]

It is really worrying that whenever a debate about CAS/ATC/GA etc starts we very soon have a "them and us" attitude developing. It is, I think, really untypical and the problems as perceived are from a very few on each side. Can we not have a little more understanding and sympathy from each other? Yes pilots should not fly so close to controlled airspace so that an infringement is more likely and equally ATC should be more in tune with difficulties faced at times by pilots, when the controller is sat in his warm office and the pilot is against the unexpected elements. I have flown as PIC (GA not CAT) in many parts of the world and found attitudes very different in different places. UK appears to be the worst for the them and us attitude.

[mm_flynn]

UK appears to be the worst for the them and us attitude.

I think this impression might be driven by the very binary nature of airspace and control in the UK. There seems to be absolute control and bandit country. The blending of levels of control and freedom that exist in many other countries doesn't really happen. Therefore, CAT pilots and controllers trying to control/operate in bandit country (i.e. EGLF) have a bigger challenge and the duty of care philosophy results in Class D being treated almost as Class B.

I think most pilots I know and most controllers I interact with try to do their best and respect the needs of the other party within the constraints of the system we operate in.

There are some occasions, however, when it does seem the deck is stacked against everyone. I had a flight from Cranfield to EGTF where - Cranfield suggested a call to Luton (who were just too busy to get the basic call sign acknowledgement in as I transited underneath their airspace). Heathrow wasn't able to provide the Burnley/Ascot transit, meaning that I was coming in between Heathrow Zone and Farnborough’s ATZ - EGLF were trying to get a jet out and found the simplest solution was to actually clear me back into Heathrow zone Direct EGTF.

I was prepared to not talk with Luton and to not get the zone transit - however, from my seat on this day it would have been a lot easier for me and Farnborough to have done the zone crossing (although clearly I have no picture as to what challenges that might have provided to the Heathrow guys). Equally, the route is intrinsically within +/- 5 miles of a lot of zones and many of the units were too loaded to even establish a minimum level of service/contact.

[Warped Factor]

mm_flynn,

The challenge for the Heathrow people is that the London Zone, being Class A, needs you to be separated by 3nm and/or 1,000ft from anything else in the Zone.

So if say someone beat you to it and was coming in the opposite direction via Ascot and Burnham, there isn't enough room available to apply the separation standards and accomodate you southbound at the same time.

EGLF would have to co-ordinate with EGLL before clearing you in to the London Zone, they are not allowed to do so off their own back, so whatever was in the way to stop your intital transit must have moved out of the way by the time you were cleared in by EGLF.

WF.

[IO540]

I think this impression might be driven by the very binary nature of airspace and control in the UK. There seems to be absolute control and bandit country. The blending of levels of control and freedom that exist in many other countries doesn't really happen. Therefore, CAT pilots and controllers trying to control/operate in bandit country (i.e. EGLF) have a bigger challenge and the duty of care philosophy results in Class D being treated almost as Class B.

HOW VERY TRUE.

The ease with which a VFR pilot can fly through anything (below Class A) in the rest of Europe (except Switzerland, IME) is astonishing and an absolute eye opener. And this includes e.g. Brussels, some of the busiest airspace around.

It can't be the traffic, it must be different attitudes.

I suppose the UK gets away with it because of the plentiful Class G. So one can always pretend that VFR traffic (and sub-airways IFR traffic too) never needs to get clearances, so why bother to give them?

After all, all the pilots need is to navigate accurately !! A fair enough attitude, OK for me and the others who have all the proper nav kit and know how to fly A-B-C-D-E but the training syllabus and establishment are still firmly stuck in WW1 practices.

I know I've said this before but IMO the only reason the situation is able to continue is because most PPLs chuck in flying very soon. So the situation never really needs to be addressed. Which is just as well because.... what is the solution?? Mandatory GPS is the only way, and nobody in the training business wants that.

[IO540]

WR

Depends on the objective. If the objective is to eliminate CAS busts then some sort of highly reliable navigation is required.

It isn't going to be achieved with better training. Just how much more training can you stuff into somebody who keeps forgetting to reset/start the stopwatch, or flies just 10 hours/year and cannot fly an accurate heading, or is flying a plane whose knackered DI drifts 10 degrees every 10 minutes... I would be busting CAS all the time if I had to fly like that, yet that is the only option for a typical new PPL!

It could be achieved with radar, mandatory Mode S, mandatory radio contact, etc, but nobody will pay for the radars or the personnel. And it would be silly.

I think one could eliminate practically all CAS busts if every plane had a decent large colour moving map GPS (not a GNS430 - map is far too small) with a current database, preferably showing a copy of the printed CAA chart.

There are other little things like elimination of RPS and QFE and getting everyone to fly on QNH only.

It won't happen, but there is no reason to not talk about it :O

[Fuji Abound]

I would not support the mandatory use of GPS. It is entirely possible and sensible to navigate accurately using only visual references.

I would support mandatory GPS training as part of the PPL syllabus.

The problem with visual references as the sole means of navigation is that it is a skill that needs to be well taught and regularly practised. The syllabus does not provide sufficient time to teach the skill. I believe this is entirely correct because the syllabus is already long enough. On the other hand there is time within the existing syllabus to introduce to pilots the use and shortcomings of GPS.

A moving map GPS supported by proper training on how to prevent a course being incorrectly entered and executed and supported by visual navigation is almost foolproof and certainly and awful lot more foolproof than anything else available to the average PPL.

Of course it is not perfect and zone infringements will still occur. However in my opinion they would be an awful lot fewer.

GA vitally needs this culture change. GPS is one of the most important pieces of equipment in the cockpit both as a navigational aid but also as a very good means of getting yourself out of trouble. It is also one of the least expensive pieces of kit. I simply have no idea why anyone would want to fly without a moving map GPS even if it was only there as a backup to visual navigation, unless you had complete confidence in your visual navigation in all circumstances (and I accept there are a few who would be able to meet that criteria).

[High Wing Drifter]

Fuji,
High Wing Drifter

How much was the map adrift by?

Why was it adrift?

How many times has it occurred?

How quickly did you identify the problem?

With respect, that was my point. Pilots say GPS is not very reliable, but never seem to set out the facts.
About 4 or 5nm. You'll have to ask Mr Honeywell why it was adrift. It happened once, since then I haven't really bothered with GPS and now the group disbanded I don't have one. Not sure how long it was like that, because I was flying with watch and chart, the GPS was on to satisfy my passenger's curiosity, but we are talking at least minutes. Before anybody suggests it, I was right and it was wrong - OK :)

I would support mandatory GPS training as part of the PPL syllabus...GPS is one of the most important pieces of equipment in the cockpit both as a navigational aid but also as a very good means of getting yourself out of trouble.
It was once said that the difference between the US and British armies is that the US man the equipment and the Brits equip the man. Anything that even remotely suggests "thou shalt use GPS" is fundementally a bad idea. What ever the reasons for pilots busting CAS, fundementally it was because they swtiched off rather than the GPS not being switched on. IMHO, to totally prevent CAS busts flying must be a simple activity, so long as man holdeth the stick and pusheth the buttons nothing will ever make flying a simple task :ok:

[IO540]

I agree 100% with Fuji Abound.

I was not after mandatory USE of GPS; it would be its inclusion in the PPL (which itself is highly unlikely) that would result in mandatory INSTALLATION in a proportion of training aircraft. Mandatory USE of anything is not enforceable (company manuals in commercial ops aside) and that's why no law prohibits any use of GPS...

Mandatory installation of GPS in all aircraft would do a lot more good than mandatory Mode S (and at a similar cost) :O

HWD - flying might have been a "simple activity" in 1930 but it isn't today.

[IO540]

I couldn't see one infringement by a 'low & slow' rag & tube type (Cub, Luscombe, Tiger Moth, Aeronca ...).

Given those types are likely to be returning a weak and fading primary return only (no transponder) they can't be easily tracked and identified.

Also without Mode C one cannot tell one has a vertical bust, in any airspace that doesn't extend to ground. Even if the bust is a bust (say in a CTR) one cannot estimate its seriousness relative to other traffic (no height info) so I would bet that reporting action is less likely to start with.

[eyeinthesky]

An interesting debate so far.

Just to concentrate the mind:

Zone infringments have been responsible for the vast majority of the serious breaches in safety in NATS airspace so far this year. Those people who seem to accept that infringements are OK (and that cutting the corner INSIDE CAS is also OK...) might not be so relaxed about it if their nearest and dearest were aboard one of the civil airliners which missed a zone infringer 'by providence' (i.e. no-one was able to take effective action to keep them apart).

I have on occasion been one of those 'right down the edge of CAS' people, thinking that it was my right to exercise my freedom in the open FIR. No longer so. Use whatever you can (GPS, Eyeball, VOR/DME) to be sure of your position, but give yourself a buffer in case of wind changes, lack of attention etc. As some have already said, if you are spending all your time concentrating on following a line on a GPS or CDI or track crawling, what are you doing to stop yourself flying into another aircraft?

[flower]

I'm quite certain that Flower can maintain a primary fix on me

Yes we can and yes we do, we even enjoy watching you hover in certain wind conditions :D

[DFC]

we even enjoy watching you hover in certain wind conditions

You must have a weird MTI to do that or do you see all the hills and buildings round the area as well?

------

While there is some merit in the them and us debate. It would be very interesting if the delays attributable to NATS each day/week/month inlcuded delays to VFR flights. Perhaps such figures would create another working group! There was a scheme to fill in a form for every refusal of a Class D transit. How many pilots have ever filled one in? Far less than have been refused a transit - which knocks a small hole in the "them and us" description.

Regards,

DFC

[Fuji Abound]

"We can be seen and tracked - but there were no reported infringements by such aircraft (the ones possibly least likely to be using moving map GPS) in that period."

The answer is far simpler.

Most pilots who fly this type of aircraft are owner operators. They are usually pilots of sound experience if for no other reason than these types demand more skills than the traditional spam can. They are also likely to be pilots who enjoy the traditional aspects of aviation and not surprisingly will therefore be ardent supporters of traditional navigation. On the whole they are just the pilots I referred to earlier who will be pretty good at visual navigation. They are also helped by flying types that are slow.

WR characteristics you may recognise?

The "problem" pilots I would hazard are the low timers flying rented aircraft or members of larger groups who do a relatively few number of hours a year or those stepping up to faster aircraft. Who among us hasn’t been there when at some point in our flying careers we needed every bit of help we could get. These are just the pilots who would avoid CAS busts if they had the help a moving map GPS can provide if only they had some training on its proper operation, and were not constantly told that they shouldn’t use this new fangled technology.

DFC - I think the point others are making is that the UK has a poor record for fitting commercial and GA traffic into CAS to the extent that many are reluctant to seek clearances and therefore attempt to route closely around CAS rather than through it. Add to this the amount of CAS in the south and the need to route around it or even between narrow blocks of it and you have a very good recipe for more CAS busts in the UK than elsewhere. The number of times I hear something along the lines "well I never talk to Gatwick, they are far too busy to want to talk to me, I feel like a nuisance" or "I would far rather route around or under solent because although I will probably get a clearance I will be held orbiting for 10 minutes and then be given a routing I didn’t ask for and didn’t want".

Mandatory reporting of failing to give CAS clearances is rather like national health waiting lists - a CAS clearance is still a CAS clearance if you could have had breakfast whilst waiting to be given it and then routed somewhere you didn’t want to go but it is as much good as the nurse assessing you in A and E in the first 10 minutes, but waiting four hours before having the fish bone removed from your throat.

[IO540]

A couple of points:

Vintage aircraft (however you define that) owners rarely fly very far. I know a fair few and they stick very much to the local area, most never venturing past a 50-100nm radius. After doing this for 30 years, you get to know the place pretty well! I would not expect the typical WW1 aircraft owner to EVER feature in CAS busts.

I WOULD expect the "younger" owners of slow planes to feature however. Speaking to one Class A ATCO recently, they do very much feature (microlights, etc).

PPLs are usually told to not talk to ATC at busy Class D airports. My PPL instructor (who claimed to hold a CAA ATPL; probably a fake like so much in aviation) told me "don't ever talk to Gatwick - they will shoot you down and destroy your confidence so much you will never want to fly again". I know it's easy (usually) to get a VFR transit through the Gatwick zone, 2400ft, but equally I rarely bother because it's easy to go round it. There is some truth in this negative approach however because one is much more likely to get a transit if calling up confidently and presenting a clear route, A-B-C-D, not "would like a transit please, south to north" especially if without a transponder.

[Fuji Abound]

"A very quick glance over the first few pages of the "Safety Investigation and Data Detarpment Occurence Listing - GA occurrences recorded between 21 May 2005 and 19 Aug 2005" seems to indicate as many infringements by King Airs, Cessna 182's and other types probably using moving map GPS as there are by Cessna 150s (which may also be using moving map GPS)."

You mention two types and a collective "other" - King Airs and Cessna 182s. There is no evidence either of these types carry moving map GPS to a greater or lesser extent than other types. There are also numerous CAS busts that go unreported so the list you refer to is unlikely to give a complete picture.

I would agree that King Air crew will not be low timers but equally the type of CAS busts with which they are involved are not typical of those that plague CZ units.

The trouble is there is not a great deal of definitive evidence whether or not the use of moving maps or other means of navigation are more or less effective in preventing CAS busts.

Perhaps following a CAS bust pilots should be required to complete a questionaire (perhaps in consideration of no further action) for a period of time. This might enable a more relaible picture to evolve of the casue (and whether or not moving maps would have helped prevent the bust).

[rustle]

Perhaps following a CAS bust pilots should be required to complete a questionaire (perhaps in consideration of no further action) for a period of time. This might enable a more relaible picture to evolve of the casue (and whether or not moving maps would have helped prevent the bust).
That's typically what happens today. (Although not a questionnaire per se).

If you bust CAS there's two things that could happen: I'm not sure of the exact form number, but I understand that a MOR is one, and there's another form filled in if the bust warrants it.

The CAA will write to you either from the "Flight Standards Officer" or from Enforcement and AFAIK this depends if only one (the MOR) or both forms are completed by ATC.

The data from the non-enforcement (FSO) is collated and AFAIK is used in coming up with recommendations.

Enforcement use a different tactic ;)

[Fuji Abound]

Rustle - but isn’t the problem (in terms of gathering useful statistical information) most CAS infringements result in a reminder from the ATCO that you have infringed - get out! It is my perception (may be wrongly) that only a very small percentage result in a follow up.

It would also be interesting what information you are asked to give on the MOR - I wonder if it is anything useful :D - fortunately I have managed to avoid seeing one :D :D .

WR - agreed. However it is my perception (and also I think IOs) that it is pretty hard to infringe CAS with a moving map GPS as long as it is turned on and you keep an occasional eye on it because it tells you exactly were you are in relation to CAS 99.9% of the time. I have yet to hear a convincing argument against using moving map GPS - those arguments along the lines they often lose signal, aren’t very accurate, are easy to enter a course incorrectly just do not wash.

[High Wing Drifter]

WR - agreed. However it is my perception (and also I think IOs) that it is pretty hard to infringe CAS with a moving map GPS as long as it is turned on and you keep an occasional eye on it because it tells you exactly were you are in relation to CAS 99.9% of the time.
If you have it setup properly. Mis-selected declutter options, databases, zoom settings, flight plans, etc can all cause you a heap of problems. GPS is just an additional layer of equipment and process that has to be got right to function properly. I really really cannot see GPS moving maps preventing 99.9% of ATZ/CAS/DXXX/etc busts for pilots who would have otherwise come a cropper.

[Fuji Abound]

"preventing 99.9% of ATZ/CAS/DXXX/etc busts"

HWD - careful - that is not what I said.

[High Wing Drifter]

Fair doos. 99.9% of CAS busts then :) Where bust = crossing the do not cross line and not busting = knowing where you are in relation to the do not cross line.

[cubflyer]

I think GPS is great and use one with a moving map display in one of my aircraft. Its not a very fancy one, a Pilot GPS III. I only know how to do "GOTO" havent bothered looking for anything more complex, but it suits my purpose, which is really to give an overview of where I am, as an aid to map reading. If I have to track closely around controlled airspace, I will do this by refering to the map and making sure I know where I am.
In the other old slow aircraft with no electrical system, I just use the map and this is fine too, but I wouldnt want to have to navigate too closely to controlled airspace, unless the features are very good. I remember a trip to Schaffen one year trying to navigate between the Brussels and Antwerp zone thur that 2 mile gap, where there are so many canals, motorways etc its hard to know where you are- much easier with the GPS!

I would totally agree that use of GPS should be in all PPL sylabuses, much more useful than ADF tracking! However, I would imagine GPS also causes quite a few infringements particularly for low time pilots relying on it too much. With poor preparation, its easy to just hit GOTO XXX and it seems that the route is fine, but with a long route and by the time you have been blown off track, your new GOTO route, takes you thru the edge of controlled airspace. Or with worse planning it went through the controlled airspace anyway without your flying being inaccurate.
I remember quite a few years ago at a PFA rally at Wroughton, when we asked someone in a large Cessna, why he had just flown right through the Lyneham zone, he said he was just following his GPS!

Using GPS is certainly advantageous, and I tend to agree that errors in the GPS position are very small and very rare. Its the user input that can be the problem!

I think the UK charts are excellent and generally very good for navigation, only bettered by the French IGN charts- agree with whoever said it that the powerlines are very useful. On both of these it is reasonably easy to figure out the controlled airspace. However I have found that the Jeppesen charts are very poor for this, it often takes a long time to find the altitude limits of complex bits of controlled airspace and the presentation just isnt very good. I wonder if a lot of people are using these nowadays, resulting in more infringements.

I also think that the differences between ATC "services" is a problem. Paris info etc has a radar, knows where you are and warns you of controlled airspace. London info is a completely different service, really it is just a frequency on which you can ask for information. I wonder how many foreign pilots think they are getting a radar service from London info and go busting through controlled airspace. I know that some do. Some ATC units even seem to think so, as they suggest you to call London info when being handed over from their zone. There is no point, unless you need to contact them for specific information.
In France you are also very rarely "cleared to enter controlled airspace" once you have called up and said where you are going, they might ask you to report somewhere, but hardly ever issue a clerance, but you are implicitly cleared through, whereas in the UK you must not enter unless given a specific clearance.

Some ATC units in the UK seem to spend time asking me what kind of service I require wanting to give me Flight Information Serivce or whatever. In most cases I am not interested in this, I just want permission to cross the zone that they have established in the way of the route I want to fly. I wonder how many times someone has been told "Flight information service" and assumed this to mean cleared to do what he asked for. I know this is incorrect, but an easy assumption to make.

It seems to me, that in some cases Controlled airspace is far too big. Now if commercial operators who want this CAS had to pay for it, into some fund kept for GA who they keep out, then maybe it wouldnt be so large! Perhaps this fund could be used to pay for extra controllers who could spend more time giving GA aircraft clearance through the zone, rather than telling them to standby, or avoid controlled airspace.

[DFC]

Isn't it funny that pilots will happily fork out £500 on an electronic piece of kit that warns the pilot every time it is turned on that it does not do what the pilot bought it for. Then they spend a few hundred pounds each year to keep the information in that piece of equipment up to date.

Ask that pilot to pay £1 in route charges for a VFR flight that obtains LARS and zone transit and all hell breaks loose.

On a more serious note. If UK controllers treated class D as the Class D described in the ICAO documents and not as their own unclassified piece of restricted/prohibited airspace that would mean that more transit flights could be accepted without impinging on the IFR flights. That would place many of the pilots trying to fly past the zone with .000001nm lateral separation within the system and make them known traffic.

The "duty of care" argument oft posed against the above is utter rubbish. How can one have a duty to do something that the written procedures clearly say you do not have to do? - Are the written procedures wrong?

I note that Edinburgh is expanding it's class D and the Class E is disapearing. What impact will that have on infringements in that area? - Will Edinburgh give transits to every VFR flight that wants to pass through the airspace that they have safely passed through without clearance for years? Why not? since the separation standards are still the same - none!

A number of posters including myself have proposed the removal of both QFE and the RPS system. Since no one has objected then perhaps that is one area in which those that debate here agree and should be taken on board.

Regards,

DFC

[IO540]

I don't think this data is collected and, if it was and it showed that using GPS makes a CAS bust less likely, it would not be publicised by CAA's GA Dept.

If the CAA had data showing GPS usage is a bad thing, they would plaster it all over the place.

Same reason why the CAA don't publicise the appalling license expiry figures - they would show the flight training industry and the CAA in very poor light. They do publicise the license award figures, of course...

Their ambivalent attitude to all this ensures these debates will run and run.

cubflyer

A few things: a GPS3 is actually a very old unit, perhaps 10 years old now. The map quality on it is very poor. If GPS was to become mainstream, one would have to provide something better (e.g. a KMD150 as a base). It does appear that many people's views on GPS (don't mean you particularly) are based on these very old designs.

As for user input, that's very true but it relates only to entering the route. One doesn't need user input to see the moving map and to use the zoom+ zoom- buttons. GPSs do have gotchas in the route entry.

Also in France you do need explicit clearance for CAS (like in the UK); they are just very casual about it. If there is no traffic to conflict, they don't see why they should make a meal of it.

DFC

You don't appear to be familiar with any real flying. Almost nobody flying VFR updates their GPS to the latest version all the time. IFR pilots flying ATS routes do (they generally have to to stay legal) but the update cost isn't as much as £500 unless you go for the full 28-way cycle. Yet the CAA expects UK VFR pilots to fly with charts up to 1 year old.

Also the customary "do not use for navigation" message is there because it's always been there (it is hoped to cover some lawyer's a**e); it doesn't relate to the requirement to use the GPS as primary nav on BRNAV routes for example.

[alphaalpha]

A small change of direction.......

Do you have difficulty judging distances when navigating visually?

I do. My RNAV or GPS tells me that my destination airfield is 4.2nm away in my half-past-eleven. But it sometimes takes me a while to spot it. I'm almost always looking too far away and I'm surprised to find the field much closer to the aeroplane.

Perhaps the same is true when, to remain outside CAS, you need to be at least (for example) 2nm west of that aerial or this river.

As has been pointed out, most useful visual checks are not on the boundary of CAS, nor are they on your desired track.

Or perhaps I've relied on radio-nav and GPS for too long???;)

AA.

[Gertrude the Wombat]

Do you have difficulty judging distances when navigating visually? Yes, I have this problem too. It was pointed out to me as a common problem during nav training: "if you should be at your next ground feature but can't see it anywhere, try a steep turn and look out of the side window - chances are it's directly below you".

It occurs to me that I don't actually know what's the nearest ground feature I can see out of the front window of the aircraft (in normal cruising configuration obviously). Two miles? Ten? From fifteen hundred feet? Nine thousand? Maybe I'll take some measurements next time I'm flying and I've got a suitably low workload.

[WorkingHard]

As said earlier "If UK controllers treated class D as the Class D described in the ICAO documents and not as their own unclassified piece of restricted/prohibited airspace that would mean that more transit flights could be accepted without impinging on the IFR flights. That would place many of the pilots trying to fly past the zone with .000001nm lateral separation within the system and make them known traffic.

The "duty of care" argument oft posed against the above is utter rubbish. How can one have a duty to do something that the written procedures clearly say you do not have to do? - Are the written procedures wrong?

I note that Edinburgh is expanding it's class D and the Class E is disapearing. What impact will that have on infringements in that area? - Will Edinburgh give transits to every VFR flight that wants to pass through the airspace that they have safely passed through without clearance for years? Why not? since the separation standards are still the same - none!"

I think this is a superb question(s) and perhaps someone in ATC who might have a better view than I could give us some guidance.

[IO540]

"But it sometimes takes me a while to spot it."

It's pretty normal for grass fields to not be spotted until one is on long final.

Occassionally tarmac ones, too. Recently I approached a well known tarmac GA airfield (~800m runway) with 3 passengers, all PPLs, and I knew where it was a) because the GPS told me and b) because I've been there before many times. None of the 3 spotted it until about 2nm. Vis was about 7000m in haze and that was about when I could see the runway myself.

Very few people admit to this. I happily do, I am sorry to say :O

[DFC]

The CAA publish a chart one per year and publish amendments as and when they occur. The only real up-to-date chart is the current edition with all the updates incorporated. Anyone do that? :)

You don't appear to be familiar with any real flying. Almost nobody flying VFR updates their GPS to the latest version all the time

There is another reason for infringements. If the database is out of date then the moving map may show incorrect airspace boundaries. For example IO540's type of real flyer could still be using the old database that caused the Kingair pilot to infringe London Zone and may continue to use it until whenever.

Unlike the CAA chart, updates for moving maps are not available unless one pays the money and most pilots really don't like spending money.

To add some more reasons;

The poor quality of the AIS briefing service resulting in poor pre-flight planning by pilots wrt temporary airspace.

Jeppesen charting services trying to fit European airspace into a US method of operation. This is worse that first appears. Look at the area between Lyneham and the London TMA on the CAA 1:500000 and look at the same on a moving map supplied by Jeppesen. Jeppesen will show the Cotswold CTA base FL105 but will not show the airway with a base of FL65.

This means that a pilot using a GP will not get an airspace warning if they accidently get too close to the airway. They may even try to underfly the Cotswold CTA and overfly Lyneham but not check the airway - slam bang and airspace infringement.

Since Jeppesen supply the database for most GPS units then most GPS units will not show airways in the UK. Look SW of Solent's airspace towards ORTAC and see if there is an airway displayed. Many other places are simply infringements waiting to happen - but for the fact that the majority of IO540's "real pilots" cruise round at 2000 to 3000ft 99% of the time.

Regards,

DFC

[IO540]

Come on DFC, show some correlation between CAS busts and (the very few) UK airspace changes, and you may be able to stretch this thread by at least another 10 posts :O

You do have a point about Jepp data not showing airways. This is a well known example of Jepp's arrogance and I wish they fixed it. But only an idiot would suggest that VFR (or IFR OCAS) flight planning should be done solely on the basis of the relatively bare airspace depiction on the Jepp GPS data. One needs to have the paper VFR chart on on's knees when flying. Or have some electronic version of the VFR chart (e.g. Memory Map for the UK, or FliteMap with the raster charts add-on for Europe).

IFR (airways) flight is routinely done using electronic data alone but that's another matter; one is under ATS control all the way so national and CAS boundaries become immaterial.

[Fuji Abound]

Re-reading this forum the words "training" keep ringing in my ears.

GPS technology is sound and reliable. It is also pretty easy to use but as always there are some pitfalls - one or two of which have been highlighted on this thread.

There would also appear to be no substantive evidence that its use helps prevent CAS busts but it would seem the general perception is that its use would help enormously.

All of which makes me wonder why on earth its use is not included in the CAA PPL syllabus? Come on CAA you have got to wake up to new technology - it doesnt mean you will be telling people it is 100% reliable all the time and it doesnt mean you need to approve GPS as the sole means of en route navigation but it does mean you have a duty to train people properly to use a bit of kit that over the next ten years will become the norm.

.. .. .. and Flower as ATCOs you need to have better data at your finger tips. CAS bust are a pain for you and you obviously do not want them to occur. Why then dont you ensure there is a proper reporting arrangement in place the object of which is to identify the cause and to publish this information in the public domain - or is it some closely guarded secret!

[alphaalpha]

Jeppesen databases for GPS:

I have GNS430 with the Central European database which I keep up to date monthly. I do not know if this database is the same as is used for other aviation GPSs.

When I bought this GPS, the Luton and Stansted CTA/CTR boundaries were accurately shown. About three years ago, after one monthly update, some of the boundaries disappeared.

I contacted Jepp, but did not get a useful reply, so I raised an MOR. This resulted in the missing boundaries being re-instated in the database one the next AIRAC cycle.

It seems that Jepp did not realise the significance of Class D airspace boundaries in the UK and applied a change, which might be OK for USA, to their worldwide database, with potentially disasterous consequences.

You certainly cannot rely on the database to show all airspace boundaries, but used in conjunction with a half-mill chart, and the distance from other aviation features screens, when necessary, you certainly can determine where you are. On balance, there is no doubt in my mind that GPS is a positive and substantial aid to reducing infringements.

Of course, you do have to look out for GPS jamming notams and do your RAIM checks, but this (together with understanding the database and when not to use the GOTO button) should be part of the training mentioned above.

AA.

[TC_LTN]

Working hard said "The "duty of care" argument oft posed against the above is utter rubbish. How can one have a duty to do something that the written procedures clearly say you do not have to do? - Are the written procedures wrong?"

The 'written procedures' include the following;

3 Control of VFR Flights

3.1 Although in Class D, E, F and G airspace separation standards are not applied, ATC has a responsibility to prevent collisions between known flights and to maintain a safe, orderly and expeditious flow of traffic. This objective is met by passing sufficient
traffic information and instructions to assist pilots to see and avoid each other. It is accepted that occasionally when workload is high, the traffic information passed on aircraft in Class F and G airspace may be generic rather than specific.

3.2 Instructions issued to VFR flights in Class D airspace are mandatory. These may comprise routeing instructions, visual holding instructions and level restrictions in order to establish a safe, orderly and expeditious flow of traffic and to provide for the effective management of overall ATC workload.

3.3 For example, routeing instructions may be issued which will reduce or eliminate points of conflict with other flights, such as final approach tracks and circuit areas, with a consequent reduction in the workload associated with passing extensive traffic
information. Visual Reference Points (VRPs) may be established to assist in the definition of frequently utilised routes and the avoidance of instrument approach and departure tracks.

I think you will find that most ATCOs have no interest in 'separating' VFR from IFR traffic in Class D airspace but given that the above is published in the MATS Part 1, few of us feel we have any alternative than to provide additional safequards/seperation than the basic ICAO definition of Class D may suggest.

[WorkingHard]

TC_LTN - I just copied it from earlier in the thread because no one had replied (Idid not see any reply). I expected you ATC guys would know far better than us pilots having a guess and you have clarified it, so thank you. Can you offer a reason for Edinburgh's need to extend the CAS? Is the flight profile changing in and out of the airport? Are newer a/c not able to climb and/or descend as before? With the existing CAS how many CAT flights were outside the protected zone? Anyone please?

[flower]

And of course all separation standards are minima.

When new CAS is established they design it as the minimum required to achieve the goal, they cannot get away with taking more than necessary.

[PPRuNe Radar]

Looking at the 'old' airspace, any CAT which was below 6000' and outwith 10NM of Edinburgh within the Class E part of the Scottish TMA airspace would have been 'unprotected' in VMC conditions.

The only protection would be 'see and be seen', as per Class G, along with information passed by the radar controller on any observed unknown traffic.

In other words, it was not a known traffic environment.

Yellow AIC (177) 87/2005 gives full details and is available on the AIS website.

As Flower says, the minimum needed for the profiles required will be what is granted by DAP, after consultation and agreement with accreditated airspace users and groups. In addition I think you will also find that there has been a 'quid pro quo' with some reduction in CAS in certain areas (raised bases, etc) to return airspace which is not needed any longer. This is the normal method employed within the UK.

[DFC]

Could another factor causing infringements (many unnoticed) is that there is an ever increasing number of aircraft permitted to fly in the UK with uncertified and uncalibrated altimeters?

Unfortunately in this respect the CAA does not have a common approach i.e.;

It is perfectly legal for an aircraft on a permit to fly using an uncertified altimeter to accept a VFR crossing of a class D CTR at say "not above 1500ft".

The only reason why the "not above 1500ft" restriction is placed on the VFR flight is because the CAA requires the controller to apply Class C airspace requirements and separate from an IFR flight passing overhead at 2500ft.

Problem is that the uncertified altimeter may be telling the pilot that they are at 1500ft but actually the 15 year old altimeter which has suffered several jolts sticks a bit and the aircraft is actually at 2000ft. :(

Thus the CAA requires an ATCO to separate flights which thanks to the CAA's own rules may get closer than the CAA would like.

Bit of a mess one thinks!

regards,

DFC

[IO540]

You could make a general rant about the general poor maintenance of UK's self fly hire Cessna/Piper fleet, but I doubt that any pilot with a functioning brain would fail to spot an altimeter which is reading 500ft wrong at the elevation of the airfield it's parked on!

I've seen loads and loads of duff instruments; in fact the planes I used to rent often had more stuff INOP than working, but I've never seen a duff altimeter.

Anyway, people with a decent installed GPS can always check the altimeter against the GPS altitude ;) I've never seen the GPS more than 50ft wrong at the known elevation.

[Warped Factor]

DFC,

Your understanding of UK ATC procedures is a bit of a mess as well.

WF.

[DFC]

Warped factor,

Please explain your interpretation of vertical separation and how it is acheived. To make it more interesting, have the permit to fly aircraft operating on a special VFR clearance in 10Km visibility and you attempt to pass an IFR flight 1000ft vertically overhead.

The simple fact is that while c of a aircraft are required to have their altimeter certified and checked on a regular basis, permit aircraft have no such restriction. Thus the CAA makes no assurance that a permit to fly aircraft will be within the required maximum permitted error for a certified aircraft. Yet the CAA allows such aircraft to use that altimeter to judge vertical separation from both other aircraft and vertical airspace boundaries.

Have you ever had a look at what some flexwing microlights use as an altimeter - you would be shocked!

-----

IO540,

I have seen an example of an altimeter being 500ft in error on an aircraft (sticky). The give away at the start fo the flight was that we were at 40,000ft + the field elevation + 150ft with the QNH set so the owner adjusted the altimeter to read field elevation ignoring the QNH provided by ATC. During the descent the altimeter would not move much unless tapped and when tapped would jump some 300ft at a time and sing back and forth over a 300ft arc. Landing with a little bump ensured that the altimeter indicated a reasonable height again. The pilot simply stated that thre was no requirement for the altimeter to be certified and that was why he could only fly the aircraft VFR by day. He explained it as ground moves away - climbing. ground gets closer descending - what more do you what. It was one of those encounters where you simply walk away shaking you head, glad to be alive!

---

Of course add that to the fact that a basic PPL is only expected to keep the aircraft within +/- 150ft of the assigned altitude when in smooth air (greather allowances for rough conditions) and there are lots of reasons why a CTA can be infringed by a pilot attempting to fly 100ft below the base.

The point is that pilots are not the sole reasons for infringements. There is a lack of joined up writing within the CAAs ATS, Certification and Pilot standards departments that could continue to cause infringements even if pilots did their best to keep clear.

Regards,

DFC

[Warped Factor]

DFC,

With reference to Class D airspace you wrote:

The only reason why the "not above 1500ft" restriction is placed on the VFR flight is because the CAA requires the controller to apply Class C airspace requirements and separate from an IFR flight passing overhead at 2500ft.

Please supply the reference for this statement.

WF.

[Warped Factor]

A deafening silence, probably because there is no such "requirement from the CAA".

One of the troubles with these sort of forums is when folk that don't really know what they're talking about post such statements of supposed fact.

Don't believe everything you read :rolleyes:

WF.

[IO540]

Always ask for references for anything like this.

[Fuji Abound]

Pardon, I heard that :O

[DFC]

Warped Factor,

3.2 Instructions issued to VFR flights in Class D airspace are mandatory. These may comprise routeing instructions, visual holding instructions and level restrictions in order to establish a safe, orderly and expeditious flow of traffic and to provide for the effective management of overall ATC workload.


The quote is from TC_LTN who included it a few posts back.

The reference I believe is MATS Part 1 but TC_LTN can confirm that I am sure.

No point in trying to comply with the above with regard to level restrictions when the aircraft you are talking to does not have and is not required to have a certified calibrated altimeter.

The only thing that a pilot is required to do in Class D airspace when VFR height wise acording to the ICAO rules is to remain 1000ft befow cloud and that is done using the eyeball not an altimeter. According to the airspace requirements there is no requirement to separate VFR from anything so why issue a level restriction ever unless one part of the CAA told you to?

So as I said, the airworthiness people are allowing aircraft to fly in airspace categories and under flight rules that on the face of it work - you steer clear of cloud and avoid everyone visually - who cares if your altimeter is out by a bit?!. Unfortunately the ATS standards end of the CAA are probably not aware that anyone is allowed to fly with uncertified altimeters and have not made any allowances for that. Not to mention the airspace designers who expect all aircraft to be able to use an accurate altimeter to avoid vertical airspace boundaries.

Don't get hung up on the idea - it is simply another posibility for airspace infringements.

Regards,

DFC

[Spitoon]

Sorry DFC but your interpretation of the MATS Part 1 is rather different to most UK controllers I've come across.

[Warped Factor]

DFC,

No hang-ups here apart from when incorrect information about the work I do on a daily basis is propagated.

I'm not involved in the certification of aeroplanes so I don't know what the requirements are for calibrating and certifying altimeters.

I am a licensed atco and atc examiner though and work in Class A and D regularly, and your previous statement that the CAA require me to separate IFR from VFR in Class D (or to pretend it's actually Class C as you put it) vertically by 1,000ft is simply wrong.

There is no such requirement or directive from the CAA, end of story.

WF.

[DFC]

Wraped Factor,

I can guarantee that your response to a VFR flight making a request to cross your class D zone or CTA through the same area that you are vectoring inbound IFR flights will not be met with an automatic - cleared to cross VFR, traffic information.......

If it is can you let us know where this unique UK CTR/CTA is! :)

On the other hand if you operate as every other UK CTR then you will perhaps through vertical separation or perhaps through specific routings that ensure some form of lateral separation restrict the profile of the VFR flight to build in some form of separation from the IFR flight.

Separating VFR from IFR is only done in class C or above - thus as soon as you restrict a VFR flight because of an IFR flight and use the words separation, you have left the realms of Cass D.

That is how it is done in practice. It is not my interpretation of anything. It is simply quoting what TC_LTN said above and based on experience. If it is not for separation then please explain why the extended routings, the level restrictions and the "remain outside" delays!

As soon as you mention Special VFR, where you are required to separate that argument falls down.

You are quite correct to say that there is no need for you to know about or even care about aircraft airworthiness certification. You should be able to operate on the basis that the CAA look after your ass in that respect......but it seems that you could place a special VFR flight 1000ft below an IFR flight but have a loss of separation - not the pilot's fault and not your fault. You still have had a loss of separation though.

Overall unless every aircraft is required to have a certified and calibrated altimeter, the CAA can not assume that pilots will not infringe vertical airspace boundaries. Since many uncertified altimeters are in aircraft with no transponder, no one knows how often or to what extent that could be a problem!

Regards,

DFC

[IO540]

DFC

no one knows how often or to what extent that could be a problem

You didn't by any chance write the DfT proposal to kick out foreign reg aircraft did you??

[Warped Factor]

DFC,

I may or may not apply a route or altitude restriction to VFR traffic transitting the zone depending on the circumstances but this will not be to necessarily achieve either 1,000ft of vertical or 3nm of lateral separation because most of the time it won't.

The point I took issue with was your claim that the CAA required me to separate IFR from VFR by 1000ft in Class D by treating the airspace as psuedo Class C.

They don't and I don't.

As soon as you mention Special VFR, where you are required to separate that argument falls down.

Why does the argument fall down? The separation rules for SVFR, where all traffic must be separated, are clearly stated and are a totally different set of circumstances.

WF.

[Bright-Ling]

DFC

On the other hand if you operate as every other UK CTR then you will perhaps through vertical separation or perhaps through specific routings that ensure some form of lateral separation restrict the profile of the VFR flight to build in some form of separation from the IFR flight.

Interesting to know that you have vast experience of EVERY CTR on the UK. Well done you.

Yes, traffic information has to be given - but that also has to be given to the IFR departure - which means calling the Tower Controller, who has to give it to the outbound IFR. ALSO remember that the IFR can request Traffic Avoidance if so desired.

Take the LCY Zone for example - off runway 28 the IFRs turn right routeing intitially up the Lea Valley area. This is where all the singles ask to be routed south bound - and the zone boundary is only 4nm away from the runway. (Not many get refused - and if they do it is more about the workload of the tower controller.)

Because of the short distance, a VFR flight may be held initially outside so that the IFR may get the Traffic Info - but not for separation purposes.

DFC - I have said this before about you. A LITTLE BIT OF KNOWLEDGE IS DANGEROUS. You are probably an expert in your own field - but stay in it and stop pontificating about something you clearly do not know lots about.

P.S. What has this got to do with the original topic?? EVEN if the majority of the Altimeters in the UK are wrong, Zones (by their definition) have a base level on the SFC. Therefore, zone busts are almost exclusively on a lateral basis.

[DFC]

ALSO remember that the IFR can request Traffic Avoidance if so desired

Now that is my field! and having passed through most of the UK Zones, I have yet to be given traffic information on a VFR flight that was restricted to 1000ft below my cleared level. Personally, I don't think it is necessary. However, it is ATC who have restricted the VFR guy when Class D specifically says - no separation. The restriction on the VFR flight is not the fault of the Commercial Operator - so stop whinging that VFR flights are getting restricted because of the rise in comercial flights at XXX regional.

- You blame us for VFR delays and we blame you for all delays! :D

As for traffic avoidance - you should remember that Traffic Avoidance and separation are two totally separate things. If are required to separate us then we expect a minimum of the required separation. Traffic avoidance - which we request from you on VFR flights (not the other way round) smply means that we will not collide.

Can't think of when we last got VFR traffic info in the Manch or Gatwick CTR/CTA (ClassD) unless it was an infringement! Either there is none or we simply are not told?

The link with the original post is that;

a) By operating more restrictive practices than Class D requires (Pseudo Class C) ATC force many VFR flights to route round the edge increasing the posibility of an infringement and increasing the posibility of collisions at choke points. and;

b) There is little point in looking at Zone infringements without looking at the many CTA infringements as well. If one simply wanted to stop zone infringements then one could simply cruise at CTA levels and then bust the CTA - no more zone infringements but lots more CTA infringements.

c) When ATC restrict a VFR flight to 1000 below our cleared level, we don't get traffic info. We also don't expect that aircraft to be a great deal closer to us than the pilot is aware of simply because the CAA allows the pilot to use an altimeter he picked up as a local junk yard sale and still has bullet holes from world war 2. That is an infringement of the rules for Class D zones!

and while I am at it,

d) The UK VMC minima in a Class D zone is an "infringement" in it's self by allowing VFR flights (UKVMC) to come very close to an IFR flight in cloud. The ICAO VMC criteria does not allow that to happen. :)

Regards,

DFC

PS, You are probably correct to say that I have not been to every CTR in the UK. Last time I was at one places they were an SRZ! Have you worked in an SRZ Brightling? Do you remember the ruels for those?