IMC Radio Question

[beechking14]

A bit rusty on UK procedures and Looking for a bit of help as unclear on what the correct Radio call / Legal Position is. A few questions I am looking for answers please.

a) On a flight say you depart Southend VFR for Exeter, ask Farnborough for basic service under VFR rules, if you later enter cloud (with an IMC rating) should you advise them from a legal and practical view point that you are no longer VFR and are now IMC and request a Traffic Service?

b) Enroute to Exeter, you are still in cloud and wish to transit say Solent zone, when you call them up although not on an IFR Flight plan do you state condition as IFR while requesting a zone transit?

c) Should a transit be denied and you continue in IMC remaining outside of CAS you can if you so choose not talk to anyone?

d)when you are then approaching Exeter and still in IMC would you advise again flight conditions as IFR even though not on an IFR Flight plan?

Thanks in advance, Flying in the US where none of this would be legal as an IMC rating does not exist has made me un clear about UK rules and procedures

[IO540]

a) On a flight say you depart Southend VFR for Exeter, ask Farnborough for basic service under VFR rules, if you later enter cloud (with an IMC rating) should you advise them from a legal and practical view point that you are no longer VFR and are now IMC and request a Traffic Service?In Class G, you are not obliged to speak to anybody. But if you are talking to say Farnborough, you should advise them if you change from VFR to IFR (if say you enter IMC).

Whether it makes any different to them, I doubt. I have never noticed anything.

Sometimes, when ATC passes me traffic info, I tell them I am in IMC and they then sometimes stop doing it. But if I was getting a report of traffic at 1 mile on a recip track, I would request what used to be called 'radar advisory', now called 'deconfliction' I think, and this request is the only way the ATCO is permitted to suggest which way you should turn to avoid. They are not allowed to make any suggestions otherwise.

b) Enroute to Exeter, you are still in cloud and wish to transit say Solent zone, when you call them up although not on an IFR Flight plan do you state condition as IFR while requesting a zone transit?Yes. In Class D, they apply different separation criteria to VFR v. IFR transits.

c) Should a transit be denied and you continue in IMC remaining outside of CAS you can if you so choose not talk to anyone? Correct.

Just keep the radio tuned to some station, in case of having to make a mayday call :)

d)when you are then approaching Exeter and still in IMC would you advise again flight conditions as IFR even though not on an IFR Flight plan?Yes.

And ask for an instrument approach (obviously).

IMHO, if you embark on a flight where there is a reasonable expectation of expecting an instrument approach, I would always phone the destination. Or file a flight plan. In fact one should always phone the destination, because many airports are PPR/PNR/all-kinds-of-crap-like-that. And the ILS or whatever might be INOP so you need to check the minima for the next one up against the actual/forecast wx, etc... airfield notams are worth getting for any serious flying, but a phone call is better :)

Thanks in advance, Flying in the US where none of this would be legal as an IMC rating does not exist has made me un clear about UK rules and proceduresHere, the existence of the IMCR and the ability to fly IFR in Class G non-radio, has made the whole subject of VFR v. IFR in Class G rather moot. You can depart (from a Class G airport) "VFR" into OVC005 and drill straight into a cloud. (Class D airports have VFR minima; typically 1200-1500ft cloudbase). In the USA they cannot bust you for not having an IFR clearance (not in Class G) but AIUI they can bust you for not having filed an IFR flight plan. Here, nobody cares.

[Johnm]

a) On a flight say you depart Southend VFR for Exeter, ask Farnborough for basic service under VFR rules, if you later enter cloud (with an IMC rating) should you advise them from a legal and practical view point that you are no longer VFR and are now IMC and request a Traffic Service?

Above the transition altitude you need to be at the proper quadrantal rule level and you'd be well advised to tell the ATSU and get a radar service. I usually settle for traffic service as deconfliction gets you vectored all over the sky avoiding traffic unlikely to be a factor.

b) Enroute to Exeter, you are still in cloud and wish to transit say Solent zone, when you call them up although not on an IFR Flight plan do you state condition as IFR while requesting a zone transit?

If in IMC your only choice is IFR transit and the ATCO needs to know that as he must meet the appropriate separation criteria.

c) Should a transit be denied and you continue in IMC remaining outside of CAS you can if you so choose not talk to anyone?

Yes but that's a bit brave especially below transition level although above everybody should be at a quadrantal level and therefore vertically separated.

d)when you are then approaching Exeter and still in IMC would you advise again flight conditions as IFR even though not on an IFR Flight plan?

Yes and also agree what instrument approach you are going to use, Exeter do a nice line in vectored ILS and will probably offer it in my experience.

[bookworm]

b) Enroute to Exeter, you are still in cloud and wish to transit say Solent zone, when you call them up although not on an IFR Flight plan do you state condition as IFR while requesting a zone transit?

The abbreviated flight plan required for controlled airspace transit is simply the set of details you pass to Solent over the radio. If you say you are IFR, then you are "on an IFR Flight Plan". However, don't expect the details to be passed on down the line.

[IO540]

Above the transition altitude you need to be at the proper quadrantal rule level and you'd be well advised to tell the ATSU and get a radar service. I usually settle for traffic service as deconfliction gets you vectored all over the sky avoiding traffic unlikely to be a factor.

Almost nobody flies at quadrantal or any other specific levels :)

If in IMC your only choice is IFR transit and the ATCO needs to know that as he must meet the appropriate separation criteria.

In Class G? Nobody will apply separation in Class G, except to traffic on a deconf service.

Yes but that's a bit brave especially below transition level although above everybody should be at a quadrantal level and therefore vertically separated.

Quad levels to not provide separation. I can still fly up the back of you, etc.

Yes and also agree what instrument approach you are going to use, Exeter do a nice line in vectored ILS and will probably offer it in my experience.

Indeed.

[beechking14]

Pretty much clarifies what I needed to know so thanks:ok:

So on this particular trip would it be better / advisable / possible to file an IFR flight plan?

Say EGMC, DET, MAY, SAM DCT ?

And if so on an IMC rating I guess below 2500ft to stay below the London TMA?

Is there any advantage doing this or just give Exeter a call with an ETA?

[mrmum]

although above... (transition level) ...everybody should be at a quadrantal level and therefore vertically separated.


Indeed, above TA, in class G, IFR you must fly quadrantals, but we're kidding ourselves if we think that's giving us much separation from other traffic. It forces all IFR aircraft in the cruise OCAS to fly at specific levels, concentrating them into layers, just because they are following vaguely similar tracks doesn't help, because as IO540 said, there can big speed differences, also two aircraft at the same QL can be on converging tracks at right angles.

It might be better to just let all the aircraft spread out to whatever level they like and rely on the big sky principle to give separation.:eek:

[flybymike]

Regarding the previous post, I think it has been mathematically demonstrated that for the reasons stated above, it is indeed safer to rely on entirely random levels rather than quandrantal ones or indeed any other fraction you can think of.

[soaringhigh650]

Whether it makes any different to them, I doubt. I have never noticed anything.


You get given more attention, or so I'm told. IFR traffic have priority over VFR traffic.

[IO540]

It is true that if you pitch up "IFR" somewhere, you do sound more like you know what you are doing. Especially if you give the next section of your route as several IFR waypoints, rather than a list of villages which the ATCO has probably never heard of.

On that basis you should be more likely to get a radar service.

So on this particular trip would it be better / advisable / possible to file an IFR flight plan?

No point. This subject is pretty complicated but basically if you file an IFR FP at a level below the airway MEAs, that FP will not go anywhere except departure and destination. It may be helpful to look for wreckage but that's about it. You may as well file it "VFR" and then you are not risking rejection by the Eurocontrol computer (all IFR FPs go to Eurocontrol for validation).

[MrAverage]

"Almost nobody flies at quadrantal or any other specific levels http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif"

I've never flown in IMC in the flight levels but assumed quads were mandatory. Is that not the case?

[IO540]

In Class G, almost nothing is mandatory.

I always fly at "odd" levels e.g. 4300ft, 3300ft, etc.

And the higher the better because the vast majority of UK PPLs fly at/below 2000ft.

Anyway, quad levels are a UK-only thing.

[beechking14]

I always fly at "odd" levels e.g. 4300ft, 3300ft, etc.



I understand why you would do that in class G, so if talking to ATC giving you a traffice service in class G , and you were in cloud, on a UK IMC you would report when checking in blah blah level 3300 IFR ?

Would that not be technically incorrect and they may question your altitude?

And then when you were ready to request the transit of say SOLENT you would presuambly want to be at an IFR level correct with semi circular rule?

[beechking14]

You may as well file it "VFR" and then you are not risking rejection by the Eurocontrol computer (all IFR FPs go to Eurocontrol for validation).

Again I understand and therefore probably a waste of time or even impossibloe to file IFR at the lower levels, and if on a UK IMC to get the correct level to be accepted I take it would be illegal.

[Johnm]

The UK is slightly odd in that anybody can choose to fly IFR in VMC it's just a set of rules. To fly in IMC you have to fly IFR and in Class G that implies quadrantal levels (the rest of the world uses semi-circular).

The IMCR allows IFR flight in the UK in Class G and Class D (BCEF are unlikely to be relevant) but not Class A where special VFR is OK down to 3km vis which are lower than the normal UK minima of 10km.

An IMCR holder cannot therefore fly airways in England but there are Class D airways in Scotland where you can.

Consequently filing an IFR flight plan for an IMCR holder is generally pointless.

To return to the original scenario of a flight along the South coast to Exeter from Southend:

You depart VFR and happily chug along at whatever altitude you want, clear of CAS, lets say via MAY and GWC. (Though you might get a transit of Gatwick if you ask!) Approaching GWC you enter cloud so adjust to the correct quadrantal for heading and call Solent "GABCD Request zone transit and traffic service" They'll ask for details and you give them including flight rules IFR.

They'll hopefully give you service and a squawk and a transit then hand you over to Bournemouth who also give you transit and service and then hand you over to Exeter. If busy they might invite you to freecall the next unit.

Job done really.

[kharmael]

It does beg the question as to why anyone would want to fly IFR, IMC, OCAS without at least a traffic service?
:ooh:

[IO540]

I understand why you would do that in class G, so if talking to ATC giving you a traffice service in class G , and you were in cloud, on a UK IMC you would report when checking in blah blah level 3300 IFR ?Sure.

Would that not be technically incorrect and they may question your altitude?Nobody will question it. In France they might... happened to me once; the ATCO asked a slightly sarcastic question to make me fly the correct semicircular level, without actually telling me what it should be ;) Normally the French are very laid back though.

And then when you were ready to request the transit of say SOLENT you would presuambly want to be at an IFR level correct with semi circular rule?That's different because Solent is Class D. They will offer you a transit at a level/altitude they prefer, say 4000ft, VFR or IFR as per your request. The moment you cross into their Class D, they will say "radar control service" and you read that back, and do as they tell you.

Note that you cannot get a transit of Solent (etc) above 5500ft because that is Class A and you can't go into that without a gold plated IFR flight plan filed previously via Eurocontrol.

if on a UK IMC to get the correct level to be accepted I take it would be illegal. Not illegal in Class G, but pointless to test the algorithms in the Brussels computer when you just want to do a Class G flight :)

The Eurocontrol computer will normally not reject routings which are a series of DCTs e.g. EGMD DCT SFD DCT GWC DCT SAM DCT EGHH at 4000ft, but historically this used to be an issue especially if you picked a route segment which happened to coincide with an airway, and then the FP got chucked out for flying below the airway MEA.

What happens with such 'low level' flight plans is unclear, and I have never found anybody in UK ATC willing to describe it (one ATCO said it is commercially confidential) but basically as far as Eurocontrol are concerned it is a valid flight plan and they distribute it to the enroute sectors as normal (I have checked this with Eurocontrol personally, very recently) but there is some person in each enroute sector who looks at it, decides it is "below him" and bins it.

So an IFR FP like the one above will go to EGMD (who will note it), EGHH (who will note it), London Control sector(s) (who will bin it because it is beneath their responsibility; they only do "proper IFR") so really it is just the same as filing EGMD DCT SFD DCT GWC DCT SAM DCT EGHH at 4000ft VFR. (which would go to EGMD, EGHH, and London Information which is the regional FIS unit).

This business of 'low level IFR flight plans' is a very tacky subject which is best avoided. Just file VFR. The fact that the whole flight will be in IMC, starting with an OVC002 departure, and ending with an ILS in OVC003, doesn't matter (in a Class D airport you will still need to go through the charade of an "IFR" departure).

And if you have an IR and really want to fly proper airways IFR then file for FL100 plus. Don't try marginal stuff like FL060... it is tempting fate because it does not look "serious" and is likely to get binned on "lack of seriousness" alone, and you need only a bit of that FL060 route to pop out into Class G and your IFR clearance will go in the bin right there, when you are airborne! I always file FL140 plus (have oxygen etc). One can always ask for a 'stop climb' when at FL100 and it is blue skies. Then of course you face the full brunt of the Eurocontrol route validation computer :) I have sent you an email with notes on this.

As Johnm above says, Class G is really easy and relaxed in the UK.

Personally, I talk to nobody unless they can offer a radar service; Southend to Exeter that might be Southend, Farnborough East (anybody tried Gatwick Director lately; I have been handed to them a few times?), Farnborough, Solent or Bournemouth. Exeter.

It does beg the question as to why anyone would want to fly IFR, IMC, OCAS without at least a traffic service?Because, when god made the sky, he made lots and lots of it :) (I don't believe in god but you get the idea - midairs in IMC in the UK, since WW2, = 0 ). 99% of UK GA is VFR only so the skies are pretty empty anyway on not-nice days.

[Toadpool]

In Class G, almost nothing is mandatory.

IO please check out rules 20, 33 and 34.

If you are not VMC, then you must comply with the IFR (rules 33 & 34 outside controlled airspace).

Rule 34 (quadrantal rule) :-

Quadrantal rule and semi-circular rule
34 (1) Subject to paragraphs (2) and (3), an aircraft in level flight above 3,000 feet above
mean sea level or above the appropriate transition altitude, whichever is the higher,
shall be flown at a level appropriate to its magnetic track, in accordance with Table 1
or Table 2, as appropriate.
(2) For the purposes of paragraph (1), the level of flight shall be measured by an altimeter
set:
(a) in the case of a flight over the United Kingdom, to a pressure setting of 1013.2
hectopascals; or
(b) in the case of any other flight, according to the system published by the
competent authority in relation to the area over which the aircraft is flying.
(3) An aircraft may be flown at a level other than the level required by paragraph (1) if it flies:
(a) in conformity with instructions given by an air traffic control unit;
(b) in accordance with notified en-route holding patterns; or
(c) in accordance with holding procedures notified in relation to an aerodrome.
(4) For the purposes of this rule 'transition altitude' means the altitude which is notified
in relation to flights over notified areas.
11 January

(my emphasis).

[mm_flynn]

Approaching GWC you enter cloud so adjust to the correct quadrantal for heading and call Solent "GABCD Request zone transit and traffic service" They'll ask for details and you give them including flight rules IFR.

In real life (not withstanding ToadPole's technically correct comment), a typical IMC OCAS flight in the South of England (as described) is heavily influenced by the overhead controlled airspace and hence has limited flexibility to comply with quadrantal altitudes (QAs). It is a system that makes sense in the absence of wide swathes of controlled airspace (i.e. post WWII Britain), and makes very little sense in Wales and Scotland (where the land pokes up into the Flight Levels, so you have to keep your other altimeter on QNH or RPS to know where the ground is relative to you.

On the hypothetical flight, from the departure to around GWC you are under the London TMA (TA 6000 ft so no QAs required below this for IFR ) and the Class A starts at between 2500 and 4500. Around GWC you are no longer under the TMA (so 'shall' adopt QAs (although the boundary of the TMA in respect of where the TA changes is not that clear looking at L620 coming out of MID with a floor of 4500, but doesn't appear to be fully contained in the TMA, but maybe it is ??). You then go for about 10 miles on 1013 (if following the rules you can only be at FL040 or FL045 depending on route, and from a practical perspective would not be able to level off at the correct QA on the way home) before entering Solent's airspace (TA 6000 ft again so back to QNH) and then leave on the other side going through Yeovilton's AIAA - which is in class G, not under a TMA so should have a TA of 3000ft, but seems to have its upper bound specified as an altitude of 6000ft rather than FL060.

Is it any wonder the whole area is often treated as 'below the TA' by pilots

[IO540]

In practice one might do the whole flight at 2400ft :) A look at the map around London will make it obvious why.

Or one can fly a bit of a longer track at do it at 3400ft. A look at the map around London will also make it obvious why.

The quad levels just don't make sense.

[soaringhigh650]

mm_flynn,

A great illustration showing how horribly complicated and potentially dangerous this flight is. http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/worry.gif

There needs to be a common TA.

[IO540]

Not really.

You are thinking of the USA, which has the very simple 18000ft system, no Class A below that, IFR flight plan file-able for any airway route which is at/above the airway MEA (or direct), Class D which can be penetrated with a 2-way radio contact (just need your callsign read back by ATC), etc.

In the UK, there is a lot of Class A (no VFR), and a lot of Class D (no entry without a clearance).

Everything else is Class G which is free for all, and that's how you use it.

Just get the map, draw a route in Class G, and fly it :)

[mm_flynn]

mm_flynn,

A great illustration showing how horribly complicated and potentially dangerous this flight is. [IMG]
...
There needs to be a common TA.

The example wasn't meant to show 'dangerous', just that the official altimeter setting procedures (which are very UK specific) aren't practical in many cases.

I find it particularly ironic that the Official Rules say that below the TA, IFR does not need to comply with QAs - for instance while negotiating the 6 mile wide and c 1000 ft vertical slot in MIG alley (BIG-OCK), yet out in the hinterlands beyond Bournemouth (above 3000 feet with no controlled airspace to funnel traffic) it is 'Critical' to comply with QAs :hmm:??

I do agree a comon TA would be a good idea - ideally at least 1000 feet above the terrain.

[Keef]

I've done this flight, as I suspect many have. No FPL, booked out from EGMC, PPR (joke!) from the other end, and off we go. IMC found part of the way, so I told whoever I was talking to that I was now IFR, and carried on. Maintained 2400 feet till clear of London, then 3400.

"Radar Control Service" here and there.

A total non-issue.

A similar flight in the USA, IFR FPL filed, flew it, also a total non-issue.