Cambridge "Airspace"
 

A few times over the past several weeks my routing has taken me directly through the Cambridge overhead - in the Class G airspace above the Cambridge ATZ but below the base of the overlying Class A airspace.

I'm aware of the instrument holding procedure above the airfield and always call Cambridge approach for at least a basic service (and to let them know I will be transiting overhead).

Recently, Cambridge approach has taken to "clearing" me for the transit, implying that they have some formal authority over an overflight outside the bounds of their ATZ. Yesterday, having made contact with Cambridge asap after leaving the Duxford frequency, the controller sounded annoyed that I had not called with regard to my (above ATZ) overflight much sooner.

Clearly I want to know if someone is holding in an area I am transiting and, appreciating that such person may be conducting instrument training, etc, I am happy to climb, deviate, etc in order not to impact their activities (and have often done so). However, it does feel like Cambridge ATC has been slightly overstepping their authority - especially since one can, quite legally, albeit foolishly, fly through that airspace all day without talking to anyone.

Hopefully this is not the start of Cambridge making a play for an necessary Class D airspace grab like Southend...

ATC in Class G?

That's ain't possible.

You either make airspace controlled so you can control the traffic.
If the airspace is uncontrolled you have no authority over it.

Hopefully this is the start of Cambridge and others wanting their much needed Class D airspace.

No different to Farnboro's constant "clearances" through their overhead at 2400' and "transit" approved while outside their ATZ. Cambridge is pretty well out there on it's own and there isn't a really good reason to overfly it, but, if that's your want, so-be it your in class G and have every right to do so. Making the calls you have is more than sufficient to assess the traffic, so why do these airfields have to assert their non existent "authority" all the time. When I was working the old adages of "custom & practice" soon became accepted as the norm and then became "the Rule" this is what they try to instill into everyone.

You do say some strange things don't you?

if their choice of language is upsetting you, why don't you just listen on their frequency without calling them? You'd know about instrument traffic they were working and could make your own mind up as to whether to avoid or carry on.


Just sayin'

surely there is no "Choice" of language in aviation RT, it should be correct, including the words "clearance" only used by ATCer's in their "bit of sky" which is clearly not the case.

So blundering across an ATZ irrespective of the "right & wrong" in class G argument at an airfield that does have a good mix of traffic on all sorts of approaches is not the best way. As I said before there is enough room around Cambridge to avoid it anyway but it's the OP's choice and lets not give these airfields the encouragement to apply for unneeded class D.

Heliplane

Why not address the perceived problem at the time? Having received a "clearance", respond with "no clearance required - remaining above the ATZ".

If the point is not taken, write to the unit Satco and raise it with him/her. Or, of course, it might have been a simple misunderstanding that you wished to transit the ATZ.

2 s

The "standby for clearance" message from ATC was met with my response that I would be above the ATZ - not as direct as no clearance required (which I may try next time) but certainly implying the same thing.

Seems to be spreading. I was working a certain ATSU with a basic service in Class G and called to say I was squawking 7000 and changing to XXXX for MATZ penetration. The reply was "If you receive no reply return to this frequency" - ok maybe it was trying to be helpful but at the time I thought under what authority they were they instructing me to do so?

I appreciate that a controllers job at somewhere like Cambridge can be challenging but we've stopped sending student cross countries there after they started getting picky about visitors at the weekend and appeared to be playing "airports".

The problem with flying "around" such places is the instrument approach traffic may well be 10 miles + from the field, so how much do you avoid?
Perhaps better to talk to them and route overhead, at least they know where you are and can negotiate safe transit.

If they get silly, ask for the SATCO's telephone number and talk to them on the ground about it, worked for me on the few occasions it has been required.

I sometimes say "I will be passing through your overhead/approach/hold at x,000', does that give you a problem?". Which in most places seems to be replied to by a request to maintain my level, which seems perfectly reasonable - I can see that it could be hard to plan if someone might be going up and down like a yo-yo.

Such posturing doesn't just affect passing aviators. It can affect nearby ATSUs. We are an autonomous radar unit operating in Class G (uncontrolled) airspace. On Jan 23rd this year I reported for TRUCE with a live target, only to find everybody from the previous TRUCE session still sitting around twiddling their thumbs. When I asked what the problem was I was told that the adjacent autonomous radar unit (which similarly operates in Class G uncontrolled airspace) had directed us to keep our target aircraft on the ground until advised solely in the interest of their own operation. Once I had climbed down from the ceiling I insisted that we launch our target, but our manager declined in the interest of inter-unit relations.

The aforementioned adjacent unit has absolutely no authority at all to restrict our, or anyone else's, operation outside regulated airspace. We have a business to run. Such restriction is nothing short of illegal.

No "clearance" required to transit an ATZ.

Correct if the atsu is AFIS or just A/G

Incorrect if ATC

A part of the ATZ for our local 'big' aerodrome (in Class G) juts out over the sea. One of our residents thinks it is clever to fly UNDER the ATZ (quite legal but very silly).
Generally, if I am able, I will go along with a 'clearance' issued to route above the ATZ, even though we both know such a 'clearance' isn't really valid with a Basic service. I do this on the basis that
a) tomorrow I might be in the overhead myself doing instrument training and appreciate the co-ordination with other traffic
b) I might need to descend into the ATZ to avoid weather etc.
We have regular liaison meetings between all the local airfields and the ATC unit where we can talk about these things over a cuppa. Don't Cambridge do the same thing?

TOO

It's pretty crazy that the instrument approach for Cambridge isn't protected airspace, considering that reasonable numbers of heavy airliners / C130s / bizjets etc all use it on a pretty regular basis.

I know it's "legal" :hmm: to do so, but it's not really common sense. If I was a controller and I had a B747 or a Herc on 4 mile final in IMC, and then a PPL made a "courtesy" contact call just to let me know that he was transiting the overhead, I'd be annoyed too. If the big guy made a go around for whatever reason, you'd be in prime position to go straight through his intakes.

But surely that is helpful?


If the transit is at 4,000' he can be asked politely not to go any lower until clear, and the airliner can be told "not above 3,000'" on the go-around.

Is it possible to fly under an ATZ?
Do you mean under the stub of a MATZ?
Warton?

If the ATZ juts out over the sea, and the airfield is above sea level, then I suppose you could technically fly below the ATZ which only goes down to ground level/field elevation?

Not only stupid but ignorant as well - it is not possible to fly 'under' an ATZ! By definition (ANO Article 258) an ATZ extends from the surface to a height of 2000ft above the level of the aerodrome. The fact that a part of the surface within the boundary of an ATZ is below aerodrome elevation is irrelevant, it is still part of the notified airspace.

No actually, also correct for an ATZ with ATC. The commander must "must obtain the permission of [ATC] to enable the flight to be conducted safely within the aerodrome traffic zone".

A "clearance" is a somewhat more formal contract with ATC. When used in it's purest sense (as in the US system) it promises some level of separation in return for agreeing to fly a specified trajectory. I would concede that in UK usage for class D, it has become little more than a "permission".

On that basis, Cambridge (who are normally pretty good at asking what service is required) should not provide a clearance if you're on a Basic Service, though it would be entirely appropriate if you agree a Procedural Service with them.

While you may be correct in your perception, I'd caution against reading too much into an ATCOs tone. All sorts of stuff can be going on to raise workload (and hackles) that you may not be aware of.

Rather debatable.

European definition...
= an ATC unit granting permission to operate in an ATZ is passing a clearance.

2 s

I did say that didn't I

Where did you find that 2s? I don't doubt it's in some EU regulation.

I agree the issue is debatable and somewhat academic.

Neither ICAO Annex 11 nor PANS-ATM define "clearance". Annex 11 does say:

3.7.1 Contents of clearances
3.7.1.1 An air traffic control clearance shall indicate:
a) aircraft identification as shown in the flight plan;
b) clearance limit;
c) route of flight;
d) level(s) of flight for the entire route or part thereof and changes of levels if required;
e) any necessary instructions or information on other matters such as approach or departure manoeuvres, communications and the time of expiry of the clearance.

I would argue that "permission granted" does not meet the spirit of this, but then neither do most of the other "clearances" used in the UK.

Hi Bookworm

ICAO Annex 2
and EU IR 923/2012 (SERA), Art 2

2 s

So it all comes down to Cambridge were not correct in giving a "Clearance" while overflying the ATZ in Class G, glad that's sorted, only took 2 pages.

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So it all comes down to Cambridge were not correct in giving a "Clearance" while overflying the ATZ in Class G, glad that's sorted, only took 2 pages.

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Simple - apart from the fact that the conclusion is incorrect. The following extracts from CAP 493: Manual of Air Traffic Services Part 1 indicate that controllers are permitted to issue clearances to aircraft ouside controlled airspace and whilst aircraft are not REQUIRED to obey there is an expectation that they will unless they advise that they cannot/will not.

Quote:

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Instructions issued by controllers to pilots operating outside controlled airspace are not mandatory; however, the services rely upon pilot compliance with the specified terms and conditions so as to promote a safer operating environment for all airspace users.

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Aircraft within an ATZ are required to comply with instructions from the ATC unit. Although flight in Class F and G airspace outside the ATZ is permitted without an ATC clearance, controllers will act on the basis that pilots will comply fully with their instructions in order to promote a safer operating environment for all airspace users.

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On 04 February 1965 I was in the right hand seat of Mrs Windsor's Argosy XR138. My captain, in the left seat, was doing his monthly training and was at the time, heads down on instruments flying an NDB hold (left hand) at the 'BO' NDB for Benson about to commence the approach.

The weather was CAVOK. As he turned off the end of the downwind leg of the hold on to the final approach course, he realised that he had turned too tightly and so he rolled the wings level to make an attack on to the ideal bearing.

It was at that moment that my world went into slow motion. I obviously couldn't see into the turn from the right seat but I suddenly had a windscreen full of BOAC VC-10 moving left to right. I grabbed control and tried to go down and right but everything had gone into very slow motion. It was like every second took an hour.

We just missed.

I saw the first officer in the VC-10 and I watched every single window in slow motion go past me. For some reason or another I do not remember seeing the wingtip.

To me, the most surreal part was watching the slightly black trail of the VC-10 engines disappearing into the distance without so much of a single degree of a heading change. They had simply not seen us.

Needless to say, we gave up what we were supposed to be doing and landed and fairly promptly, went down to the Farmers Man in Benson village for a quick nervous breakdown.

A couple of weeks later, I was called by a Wg Cdr in Flight Safety at MOD and he wanted to know how I knew that the VC-10 concerned was G-ARVH. I told him that I had read it off the tail-bullet. "Bloody Hell" said he "you must have been close!"

It transpired that the VC-10 was on its way from Wisley to Bedford to do some blind landing trials and they had decided to go VFR at 3,000 feet via Woodley and they admitted afterwards that they had disgegarded military holding patterns for Benson, to them, Benson was simply an ATZ.

I dreamed about the encounter for quite a while.

I therefore find it quite pathetic to find fellow private pilots (I presume) arguing about the semantics of what they think an ATC unit actually said to them which so upset their afternoon bimble when THEY KNOW THEIR RIGHTS!

For God's sake people, communicate with one another. It is quite amazing what you can achieve if you are nice to each other.

It is so much better than waking up in the middle of the night in a muck sweat trying to work out why you are still alive despite others.

JW411
Well said sir.
Makes a nonsense of the whole "I have my rights" debate.:ok::ok:

As the OP wasn't "arriving" ie landing" this quote is irrelevant.


As the OP was outside the ATZ the first part of quote is irrelevant. The rest fails to take account of the current "ATSOCAS" requirements

Is the manual required reading/study for ppl's?

Would you not associate "place themselves under the control of" with acceptance of a procedural service though?

As ATSOCAS exists, a "procedural" service is

As a "deconfliction/procedural" is only available to flight under IFR the OP cannot comply/request if VFR.

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Is the manual (of Air Traffic Services Part 1) required reading/study for ppl's?

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Not normally, but if one is going to publicly claim that ATCO's are not doing their job correctly by exceeding their powers, as done early in this thread, then it is helpful to know their job description as laid down in their ‘bible’ MATS Part 1. MATS Part 2 also exists but is not generally available since it is each unit's local procedures as approved by the CAA.


For what it's worth, I frequently fly a glider in the vicinity of Cambridge Airport under a basic service and feel that I get an excellent service. Sometimes I get a clearance I cannot comply with (like maintain 4,000’ – but to be fair that’s more likely to come from Lakenheath), I explain why I cannot comply and come to a more appropriate agreement. It’s not a problem.
Especially when they have instrument traffic in the hold, or on approach outside controlled airspace, working in the way laid down in MATS Part 1 creates a safer environment for all. Most of the instrument traffic seems to be training in light aircraft with relatively few commercial movements.




Willing acceptance of and compliance with their clearances OCAS is to our benefit since they are LESS likely to feel they have to go for Class D which means that we can be excluded.

Dialogue is usually along lines:

Pass your message.

Glider XXX is 4 miles North West of your field at 4000’ routing overhead towards the wind farm. Request Basic Service.

Glider XXX, QNH is nnnn. Basic Service. Report descending below 2500’.

Nnnn, Basic Service. WILCO. Glider XXX


However on occasion I have been “cleared” overhead. Sometimes I'm instructed to report on reaching a certain point such as overhead or after completion of crossing of extended centre-line etc..

Flying overhead Cranfield a very common experience is I report my level and routing (via the beacon), and they ask if I am VFR or IFR. In the usual UK 'IFR exists only in your own head OCAS' situation, I am usually IFR, I.e. I have chosen a level consistent with my heading IFR and am above MSA so I can be IFR if I want.

They don't want me IFR because they will then have to deconfiict me from the IFR training traffic so they usually request I overfly them VFR. If I am in VMC I comply but it does make a bit of a nonsense of the idea of procedural deconfliction...

Provided, of course, that you have a valid instrument rating.

They don't want me IFR because they will then have to deconfiict me from the IFR training traffic


No, they don't - not if you request only a BS.


2 s

I passed by Cranfield the other day and gave them my estimate and level for the CIT, which happened to be directly on my route, which might have made me sound like IFR traffic. They seemed quite keen to make it clear that they were treating me as VFR - didn't bother me one way or the other!

In the UK is it accurate to say that when crossing CAS asking for a "clearance" implies IFR, asking for a "transition" is VFR?

No. I've not heard transition used in the UK. Nearest is clearance to transit.
Either way ATC will ask if you are VFR or IFR.

D.O.