Help a US Controller Understand RAS...

[av8boy]

In an effort to educate myself as to the black magic of my ATC brethren in the UK, I've been doing some reading. Today I was looking at AIC 119/2006 (Pink 107) to try to work out RAS/RIS and draw analogies to ops in the US, and I saw this...


...Under a RAS the following conditions apply:
(a) The service will only be provided to flights under Instrument Flight Rules (IFR) irrespective of meteorological conditions;
(b) controllers will expect the pilot to accept vectors or level allocations which may require flight in Instrument Meteorological Conditions (IMC). Pilots not qualified to fly in IMC should accept a RAS only where compliance with ATC advice permits the flight to be continued VMC;
(c) controllers should be aware that pilots may not be qualified to fly in IMC although operating under IFR...


I double-checked MATS Part 1 (the nice new one coming out later this month) to ensure this wasn't an anomaly, and found the same info in Chapter 5, Section 1.4.

So, my question... How is it that you can have an IFR ticket in the UK but not be qualified to fly in IMC? This may just be something I've missed, in that I don't have an IFR ticket, but I've been in the business on the ATC side for 26 years and it's never occurred to me that someone licensed for IFR would not be able to fly in IMC.

Please, edumacate me!

Dave

[spekesoftly]

Dave,

Look at it this way. Pilots that are not quailified to fly in IMC may still elect to fly in accordance with the Instrument Flight Rules, outside controlled airspace.

[av8boy]

Perhaps I require a better understanding of what "...flight under Instrument Flight Rules (IFR)..." means in the UK. I got the impression from this:
(a) The service will only be provided to flights under Instrument Flight Rules (IFR) irrespective of meteorological conditions;
...that RAS required the aircraft to be on in instrument flight plan. Isn't a pilot on an instrument flight plan, by definition, capable of flight into IMC?

On the other hand, a VFR pilot flying in VMC and navigating via instruments isn't really flying under Instrument Flight Rules, is he? He's flying under Visual Flight Rules, right? Or where have I gone wrong?

Thanks for the help.

Dave

[rodan]

Anyone can fly IFR outside controlled airspace, as long as they comply with the Instrument Flight Rules which are (in the UK at least):
SECTION VI INSTRUMENT FLIGHT RULES
Instrument Flight Rules
28
(1) In relation to flights within controlled airspace rules 29, 31 and 32 shall be the Instrument Flight Rules.

(2) In relation to flights outside controlled airspace rules 29 and 30 shall be the instrument Flight Rules.

Minimum height

29
Without prejudice to the provisions of rule 5, in order to comply with the Instrument Flight Rules an aircraft shall not fly at a height of less than 1000 feet above the highest obstacle within a distance of 5 nautical miles of the aircraft unless:

(a) it is necessary for the aircraft to do so in order to take off or land;

(b) the aircraft is flying on a route notified for the purposes of this rule;

(c) the aircraft has been otherwise authorised by the competent authority; or

(d) the aircraft is flying at an altitude not exceeding 3000 feet above mean sea level and remains clear of cloud and in sight of the surface.


Quadrantal rule and semi-circular rule

30
(1) Subject to paragraph (2), in order to comply with the Instrument Flight Rules, an aircraft when in level flight above 3000 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 the appropriate Table set forth in this rule. 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.

(2) An aircraft may be flown at a level other than the level required by paragraph (1) if it is flying in conformity with instructions given by an air traffic control unit or in accordance with notified en route holding patterns or in accordance with holding procedures notified in relation to an aerodrome.

(3) For the purposes of this rule ‘transition altitude’ means the altitude so notified in relation to flight over such area or areas as may be notified.
So a vanilla PPL can fly IFR (outside CAS) if he obeys those two rules (29 & 30) and remains VMC - flying IFR is a seperate issue from flying in IMC.
Hope that makes sense!

[Say Again, Over!]

Interesting discussion!

On this side of the pond, an aircraft we refer to as "flying IFR" is an aircraft on an IFR flight plan with a qualified IFR pilot at the helm.

Here, anybody can fly an airway and shoot approaches in controlled or uncontrolled airspace under VFR, so long as they do remain in VMC.

If you're not IFR certified, you cannot enter cloud. No matter what class of airspace you're in.

Semantics, I guess?

Felix

[spekesoftly]

Refreshingly uncomplicated, I wish!

[bookworm]

So, my question... How is it that you can have an IFR ticket in the UK but not be qualified to fly in IMC? This may just be something I've missed, in that I don't have an IFR ticket, but I've been in the business on the ATC side for 26 years and it's never occurred to me that someone licensed for IFR would not be able to fly in IMC.

Couple of differences to appreciate as background.

* The UK does not permit VFR at night. All flight at night has to be IFR or SVFR (in a control zone).

* The UK has very little class E airspace -- the vast bulk of low level airspace is A or G. IFR in class G is standard practice, is the only way of going through class G at night, and is based on (as rodan quoted) the quadrantal rule for keeping aircraft apart from each other and the minimum height rule for keeping aircraft apart from terrain and obstacles. Radar information and advisory services are available to reduce the residual risk.

With that in mind, it makes more sense to set licence privilege restrictions outside controlled airspace in terms of weather minima, not flight rules. Thus we don't have "IFR tickets" as such, at least for flight outside controlled airspace. A pilot without an instrument ticket of any sort is limited to a minimum flight visibility of 3 km.

...that RAS required the aircraft to be on in instrument flight plan. Isn't a pilot on an instrument flight plan, by definition, capable of flight into IMC?

The idea of an "instrument flight plan" is also alien to us for operations outside controlled airspace, at least in the way you think of it. Flights outside controlled airspace do not require a clearance to fly IFR, so they can switch at will between VFR and IFR (provided they obey one or the other). While a FPL can be submitted for flights outside controlled airspace, the initial choice of flight rules is not limiting.

All that said, except at night, it would be unusual for a flight operated visually by a pilot without an instrument ticket to claim to be IFR simply to receive a RAS.

Within controlled airspace, the UK is much more normal (if there is a "normal"). An instrument ticket is required for IFR, a FPL and ATC clearance is required, and IFR flights are separated by ATC.

Finally, worth adding that the RAS-only-for-IFR rule was introduced maybe 10 years ago. Previously, a RAS could be given to VFR flights -- IMHO that made a lot more sense: if you can't sight the traffic, you may need avoiding action, whether you're VFR or IFR.

[Knackers]

Seems that Downunder we follow the US/Canadian system.

So, in the UK, a VFR aircraft in G would call you up, tell you he's going IFR, you would then allocate a transponder code and input some flight plan details?

[av8boy]

It's beginning to make sense. Different system! Never would have guessed!

Called-up my best friend who is an ex flight instructor and, for the last 15 years or so, a pilot for Delta, and asked him about this. Shocked I say. Shocked. In the US an IFR rating automatically confers a right to fly in IMC, and you don't play the IFR thing unless you hold such a rating. Guess I wasn't as daft as I feared. Just a different way of doing things.

Thanks very much for all the info though...

Dave

[rodan]

In the US an IFR rating automatically confers a right to fly in IMC
As does an Instrument Rating in the UK. But just to re-iterate, no rating is required to fly IFR outside CAS if one is remaining VMC.

So, in the UK, a VFR aircraft in G would call you up, tell you he's going IFR, you would then allocate a transponder code and input some flight plan details?
Depends who 'you' is. There is no need for a flight plan to fly IFR outside CAS, and there is no need to speak to anybody either. 'So how is seperation ensured between two a/c in IMC who aren't talking to anyone?' I hear you ask. Well, it's a very big sky, you see...

[Knackers]

I like the Big Sky Theory...but the boss won't let me use it!

[BurglarsDog]

Hi a useful thread

But the Big sky theory dont always work in the UK; remember CARNO ; Jaguar tandem, doing 420kts low level, hit a lighty taking pics over the village of CARNO wales. Sad day for all and espeiually tragic as one of the jaguar pilots had recently returned to ops after a heart lung transplant.

Also the F15 s that sadly crashed in Scotland a few year back due in part to the misunderstanding of controller / pilot responsibilities under the British RAS service. All very sad so good that more understanding about some uniques practices is spread about a bit.

Im sure there are many on here more up to speed with todays specifics of the JSP522 and RAF ATC system but Ill try and put a bit of colour on the canvass from my memoirs of 10 years ago!!

Basically, ICAO based civil ATC separation is provided to acft according firstly to their status i.e. IFR or VFR/SVFR, and secondly according to the classification of airspace they are in at the time. So in class C, IFR and VFR are separated. But in class D; IFR v VFR are not separated and traffic info is passed. No sep standard needs to be proven as in class G no ICAO separation standard is required at all.

Now although the standard ICAO airspace classifications are used, the UK has a relatively small airspace, but with a high density and complexity of users. Controlled airspace, in the form of airways and control areas and zones is established around the country joining the major airports and linking the major inbound & outbound en route airways structure. Commercial acft therein and mil flying under civvy airways rules, are controlled by Civilian controllers as per the world over, applying the above separation rules.

However, the majority of airspace below FL240 (?) is uncontrolled; class G and this is the realm of the military ATCO. His / her rules of engagement are designed to meet the main users need i.e. Tactical Freedom.; e.g. this allows an aircraft to launch in Wales and fly low level to Scotland without filing a flight plan. The acft also has no legal requirement to seek an ATC service unless penetrating controlled airspace (I think). As already mentioned, under ICAO airspace classsification system, no separation is provided by ATC in class G . In most parts of the world, most users would predominantly be pilots flying under VFR anyway, in low density airspace (guessing here). However in the UK with poor weather, many fast movers, commercial jets going to airports not linked by CAS (Norwich?) ,and lots of inexperienced light aircraft some form of control is desirable.

So, firstly the UK has implemented a few rules and an additional standard to the IFR semicircular rule - known as the Quadrantal system; whereby any aircraft flying in IMC above the Transition level (fixed at FL30 in England & Wales I think? ( and therefore IFR qualified to do so) must fly at either an odd FL, an odd FL plus 500”, an even FL, or an even plus 500’ ; depending on his magnetic track; e.g. . 000-089degs 090 – 179 degs etc. Therefore , it is hoped that opposite direction traffic flying in IMC and in the cruise/ transit , dont meet.

Doesn’t do a lot for climbs and descents though.

So… and secondly, with a good overlap and base of radar coverage throughout the country the Mil ATC units and some civilian Lower airspace units, are able to provide a more effective separation / radar service on request to this multitude of airspace users.

Forget ICAO rules now.

On request, and in agreement with a controller, ( so subject to workload etc) , a pilot can
request either:
a Radar Advisory Service -RAS
a Radar Information Service or
a Flight Information Service from ATC.
Depending on his situation, tactical requirements, and weather conditions at the time.

Under a RAS, ATC pass 3D details of conflicting traffic along with advice necessary to resolve the confliction (climb descend turn) , where possible to achieve a standard separation distance –, 5 nm, 1000’ etc. There are also some specific and unique UK rules to using indicated mode C readouts for separation.


At all times the pilot is responsible for terrain avoidance - so ATC can only provide this service above a minimum vector altitude marked on the radar video map. Additionally as any instruction could take the aircraft into cloud (which ATC cant see) the pilot must be suitably qualified. These days he has to be IFR qualified to get a RAS - though 10 years ago in my day the term IFR wasn’t used or subsequently logged anywhere. There are also rules for the pilot to adhere to ; like not turning without advising ATC first ( as the same controller may have two opposite directions tracks at the same level and be vectoring them to achieve the 5nm sep for example. Any unplanned deviation by one would loose the standard sep. Once clear of the traffic the pilot is given a position update, advised to resume own nav has his RAS cancelled and generally he goes off freq back to his “quiet” operational frequency. So anyone taking this service can be vectored about a bit – which may cause a delay and not be strictly necessary on a rare sunny day.

A RIS on the other hand is more often requested by those happy to take their own visual separation and not wishing to take avoiding action instructions. Here traffic is passed and updated until clear. No maneuvering advice is passed and no sep standard has to be achieved. Onus is on the pilot. Acft can change heading without first advising ATC as no standard is being achieved other than pilot visal sep. This allows Tactical freedom for Fast Jet formations on a nice day and for light aircraft doing aerobatics etc..


Although this type of controlling is very reactive it is quite unique I think to teh RAF. (Please correct....) and alien to the Oz mil for example. But with no control over any airspace it works in the Uk ( for the most part). It makes the job very interesting and demanding when busy. But due to the lack of ICAOness ( e.g. no procedural standards of control) it results in a reporogramming of your ATC control technique theoretical knowledge chip necesary for anyone looking to leave the blue suite and join the civs in the UK. – unlike Oz where the same ICAO based MATS document, and rules and procedures etc are used by both sides.

Hope this expands a little on what’s already been said.:uhoh:

Happy to take corrections or PMs.:ok:


DogGone.





.

[bookworm]

So, firstly the UK has implemented a few rules and an additional standard to the IFR semicircular rule - known as the Quadrantal system;

FWIW I think the quadrantal rule used to be ICAO standard outside controlled airspace.

And it makes sense outside controlled airspace, as you're trying to use levels to separate even IFR flights from each other as much as possible. When you move to class E airspace, the situation changes: IFR flights are separated from each other by ATC, so the next priority is to separate the IFR flights from the uncontrolled and possibly unknown VFR flights using levels -- hence the ICAO semicircular rule.

[Spangly]

Although this type of controlling is very reactive it is quite unique I think to the RAF. (Please correct....)
Used to do pretty much this at Farnborough as a civvy. Very few (if any?) pilots understood that they had to be IFR if they wanted a RAS, but as they were outside controlled airspace, being IFR wasn't actually very onerous, and they don't even have to fly quadrantal levels if in receipt of heading instructions from a controller. Basically in that case, just observe the min height rule, and we wouldn't vector at an altitude below minimum radar vectoring altitude, so no problem there either.

[NorthSouth]

av8boy:
Another difference that might help you to understand it is that in the UK there are relatively few light aircraft pilots with a full Instrument Rating (what you might call an "IFR ticket"). Most PPLs with an instrument qualification have what's called an IMC Rating. This allows you to fly IFR in Class D and E airspace, including flying instrument approaches, but (a) you're not allowed to fly in airways (except the few bits that are Class D) and (b) you're not allowed to fly down to IR minima on approach, nor on takeoff. So your idea of anyone with an "IFR ticket" being able to do anything IFR doesn't fit over here.
As someone else said, IFR isn't a capability to fly in IMC; it's a set of rules which a pilot can choose to fly by irrespective of the weather conditions.
NS

[chrisbl]

and (b) you're not allowed to fly down to IR minima on approach, nor on takeoff. So your idea of anyone with an "IFR ticket" being able to do anything IFR doesn't fit over here.


Strictly it is a recommendation not to fly down to the charted minima rather than an outright prohibition.

[NorthSouth]

Strictly it is a recommendation not to fly down to the charted minima rather than an outright prohibitionFor the vertical minima yes, but the 'no landing or takeoff in vis less than 1800 metres' is a legal requirement.
NS

[Scott Voigt]

Dave;

Don't feel bad about being confused... I have spent many hours plugged in at different UK facilities and it still confuses me from time to time about the different rules with the different airspaces... It is quite different from what you and I are used to, and there are far more areas of class G then we are used to... Our airspace and system actually seems much simpler for both pilots and controllers.

regards

Scott

PS. You ready to retire yet???

[BurglarsDog]

Bookworm.
If you have access to the docs,check Doc 4444 and ICAO Annex 2.
I dont think you will find the UK Quandrantal system defined therein. So it aint ICAO.
Also the Semicircular rule (which IS outlined within the ICAO Docs mentioned doesnt start until above FL240 (I think) . So not applicable in class E . This is / was designed to take into account pressure errors in altimetres at high level and afford an extra margin of safety on opposite tracks . i.e 2000 rather than the standard 1000' below the cut off altitude. With the implementation of RVSM the semi circular rule is becoming obsolete -unless of course aircraft arent fitted with the pre requisite of a more accurate transponder.
DogGone:ok:

[bookworm]

used to be

To be precise, the semi-circular table replaced the quadrantal table in Annex 2 Rules of the Air in 1966.

Also the Semicircular rule (which IS outlined within the ICAO Docs mentioned doesnt start until above FL240 (I think).

No, the semicircular rule as defined by ICAO applies above 3000 agl by default, to both VFR and IFR flights.

The UK "semicircular rule" is indeed quite different. It applies to IFR flights above FL245 outside controlled airspace, and thus appears to be as useful as a chocolate teapot.

[chevvron]

And now some idiot has proposed replacing RAS, RIS and FIS with 5 types of service; as if it isn't complicated enough for pilots already!!

[Say Again, Over!]

:ooh:
Riiiiiiight! I still don't get it! :{

Explain to me, please, what flying IFR outside CAS in VMC only means. If you're restricted to VMC why not simply continue VFR? There's something I'm missing... :ugh:

Is it that when you're IFR, even though you'll stay in VMC, ATC provides you with IFR separation standards? Kinda like our Controlled VFR (CVFR) in Canada, above 12,500?

Help me....... :{

Felix

[BurglarsDog]

BW

1966 A good year for the POMS; England won the world cup 4-1 Jeff Hurst scored a hat trick!!

Always good to debate the rules and give others a pointer as to where to look if they have access to the docs... and keep reading , thinking and asking questions of their trade of course!

Must admit Im typing from memory as I dont have any hard copies to hand - so always happy to stand corrected .

But Ive dug out a 2005 version of Annex 2 and Appendix 3 lists the VFR / IFR alt tables under discussion. It appears to start at 1000' for IFR though, not 3000? Doesnt matter either way.

Havnet got Doc 4444 but would be interested in knowing where an electronic copy may be available from.

DogGone:ok:

[Greebson]

Say Again
A RAS is the only way pilots in Class G airspace can be given info necessary to resolve any confliction (avoiding action).
Pilots request a RAS, the controller doesn't necessarily know if the pilot is not IMC rated because the service is always provided as if the flight is an IFR flight.
If the controller gives the pilot an instruction (service is advisory but advice is given in the form of an instruction) that requires flight in IMC, the pilot is responsible for saying he can't take the manoeuvre. The service is then downgrade to a RIS and only traffic info is passed from then on in. Or, put another way, the pilot is thrown to the dogs.
In essence, it's the only way a flight being conducted in VMC in Class F and G airspace can be given instructions to resolve a confliction.
The Greebs

[av8boy]

Got to admit, this is turning out to be much more interesting than I could have guessed! Thanks again to everyone.

BurglarsDog...

Look here for 4444 et al...
http://dcaa.slv.dk:8000/icaodocs/


Scott...
Isn't everyone? :)


Dave

[Dances with Boffins]

One simple word - NIGHT.

In the US you can [or could] fly VFR at night. Not over here - you need to fly IFR outside of CAS. You only need a night-rating to do it, so no IMC rating or qualification is necessary. Hence IFR is mandatory outside of IMC conditions. We do Special VFR in CAS, which will only confuse you, so I won't go there. :ugh:

Outside CAS over here means a large proportion of our airspace, unlike y'all, where it means on top of the Rockies.:rolleyes:

[bookworm]

BD

1966 A good year for the POMS; England won the world cup 4-1 Jeff Hurst scored a hat trick!!

I'm married to a football-loving Hun so my keyboard is wired to give me a nasty electric shock if I type the digits 196 -oooowwww! ;) Glad you mentioned it though.

But Ive dug out a 2005 version of Annex 2 and Appendix 3 lists the VFR / IFR alt tables under discussion. It appears to start at 1000' for IFR though, not 3000? Doesnt matter either way.


That's correct. 5.3.1 requires IFR flights outside controlled airspace to adhere to these levels "unless otherwise specified by the appropriate ATS authority for flight below 3000 amsl". The UK puts no restrictions on IFR levels below 3000 ft (except min alt) but other states do.

[BurglarsDog]

AV8Boy
Thanks for the ref. Will have a peep.
Always keen to get my mits on some free DOCs -even if they are written by some French Dude living in Canada under the direction of ICAO!!
Bearing in mind the new English Language requirements, surely someone with English as their first language will rewrite the Docs sometime soon?? Mon Dieu even fancy that job myself sometimes!!
Bookworm- Greatest British Superhero was not David Beckham but World Cup Willy - and that has nothing to do with brewers droop!!
All - I suppose a solid unbiased thread like this does a lot to highlight the different International interpretations of ICAO based Documentation. I for one have had more than one lively discussion on console regarding interpretation of a particular rule on a particular day in a particular situation. Certainly ads nothing to the ATC safety case! And Ive always thought that if ATC can be confused by the rules, then what of the aircrew? Hate to be an International pilot flying longhaul for example. Take off in Oz and get one fairly anal (though generally safe) interpretion , fly to NZ and get another , jump the pond to yet another culture, and finally land in Blighty with yet another slant on things - of course different crew.
I think we as ATC assume that what we do is how others also do it - after all our countries adopt ICAO's SARPS etc dont they?
But there are many differences - as this RAS thread has highlighted ( Not an ICAO based procedure though - Stand to be corrected by BW).
Maybe the new common European license may go someway to standardising some ATC related "things"!

DogGone:ok:

[BurglarsDog]

Greebson
I think not!
The only way you can get any reliable, first hand info about conficting traffic OCTA, is to look out the fricken window.

I seem to remember the phrases: Lookout attitude instuments from my early jet days ! Always remember a Lightning pass about ???' below during a series of spins over Holme on Spalding Moor. It was close but we didnt collide so the big sky theory obviously worked!! In UK this is de rigeur and par for the course. Lookout the window and see and avoid is the big sky theory of class G in Uk. ATC provisioned RAS or RIS is an add on luxury - and who pays for this ?? . Infact a luxury most of the rest of the world doesnt offer; due to cost, lack of radar coverage, training , controllers etc etc.

Ive watched in horror as acft have manoeuvred in restricted airpsace and get extremely closei n Oz; but operating on quite freq . One day ....Big sky wont feature!!!

For mil or tactical ops, or ops within busy environments, RAS and RIS are very effective ways of separating traffic outside CAS. But you ned bums on seats in ATC and the prerequisite "reactive" skill sets.

DogGone:ok:

[fyrefli]

As does an Instrument Rating in the UK. But just to re-iterate, no rating is required to fly IFR outside CAS if one is remaining VMC.

...or a glider using cloud flying / below VMC minima dispensation. (That usually sets the cat amongst the pigeons) :)

[chelseaafc]

Sorry mate, but I find the easiest way for an american or an Oz to understand is that UK people want things without paying for it. Business men are mighty and rather than pay for IFR training they get the CAA to approve a service that they have not paid for ie; fly VFR but talk to a radar unit, get a RAS, that way you don't need to look 360 degrees, just get someone else to do it for you. I dont like to slag our own but its all about the lazy selfish Brit. I hope that helps:hmm:

[Say Again, Over!]

I think I'm starting to get it...

So, if I do understand, a pilot on an RAS is separated from other IFR aircraft by 3 or 5 miles depending on the class of airspace, receiving IFR separation even though he's bound to VMC?

An RIS however, is simply like what we call flight following?

Thanks for all the replies!

SAO

[chelseaafc]

He's seperated from IFR or VFR traffic by 3/5 miles unless he elects not to be:} :ugh:

[mm_flynn]

A couple of points to remember about Class G UK flying

ATC has no way of knowing during the day if a flight is IFR or VFR (unless the pilot tells him)
IFR or VFR for the pilot is a 'state of mind' if the weather is VMC. With a few special exceptions, VFR recommended practice and IFR are the same in class G.
The are no controller observable differences between an aircraft operating IFR or VFR in IMC conditions (obviously you can not legally be VFR in IMC).
There is only one operational limit that being IMC places on the pilot over the visual flight rules and that is - to be 1000 feet above the highest obstace within 5 miles.


So, if I do understand, a pilot on an RAS is separated from other IFR aircraft by 3 or 5 miles depending on the class of airspace, receiving IFR separation even though he's bound to VMC?

Separated from all traffic because the controller doesn't know who is IFR or VFR at any given moment.

No requirement at all for anyone to be VMC

An RIS however, is simply like what we call flight following?

Broadly yes - but only available OCAS

[av8boy]

Separated from all traffic because the controller doesn't know who is IFR or VFR at any given moment.


Etc...

I'm glad I always say, "Live and learn." Interesting old world, eh?

Dave



Edited to say, I'm glad that this, my 600th post, was good-natured! :)

[London Mil]

Think of RAS like flight following with the addition of collision avoidance advice. ATC will separate all traffic participating in the RAS but non-participating traffic will be called and an advisory avoiding action given. There is no guarantee that ATC will achieve standard separation against non-participating traffic (5nm or vertical). Whether you take that advice is entirely up to you. If you choose not to, then you accept all responsibility for avoiding that particular aircraft (normal rules of the air still apply).
An aircraft under a RAS is not bound to be VMC - he can be either VMC or IMC. The driver here is that the conditions of your pilot's licence dictate whether you can fly IMC. If you cannot, you are only allowed to take a RAS if you can maintain VMC. The only important bit of UK IFR in this scenario is that you must be terrain safe to fly IFR; therefore the only link between IFR and RAS is that you must be IFR (ie terrain safe) to accept/give a RAS.
Confused? It actually works quite well although there are bits that are broken. As someone has hinted, there is a review going on and some wag has thought up a more complex set of draft rules. Personally, I would just love to go IFR or VFR - if you are IFR ATC would provide separation, if VFR they would provide 'flight following'. The arguing seems to be over the level of service required (or to be more precise, the amount of detail provided and controller reponsibilities) under the 'flight following' model.

[Pierre Argh]

LonMil, I'm guessing you're an experienced military controller, used to working in both regulated and unregulated airspace? When you say I would just love to go IFR or VFR - if you are IFR ATC would provide separation, if VFR they would provide 'flight following' I wonder how you'd provide separation in Class G when mixing it with VFR traffic? All pilots are responsible for avoiding collisions, but the VFR pilot can apply normal ROA rules and does not have to maintain standard separation (he could theoretically adopt lose formation is so wished?), and is under no obligation to speak to anyone on RT. An interesting theory, but a simplication that surely would fall down in practice?

[London Mil]

I agree that Class G would be a dog's dinner but if we actually looked at some other ICAO airspace classifications? E sort of works. Either that or shoot off down the Eurocontrol route of intended and unknown. Obviously that is going to drag us into the Mode S argument; something better discussed on the GA forum. :eek:

[PantLoad]

In the U.K....It's like being a little bit pregnant.

In the U.S....You're either pregnant or your not.


PantLoad

[BurglarsDog]

I think it worth remembering here that RAS and RIS has evolved to suit one need of one particlar customer; Tactical Freedom of the military . And in particular the operational requirements of fast moving aircraft flying in the lower airspace and mixing it with the increasing number of light aircraft. Generally Mil V Civil RPT is not a problem unless the civil are off route or on an advisory route, (sep only from participating traffic = other civil IFR) as they stay inside class c/d and the fast jets stay outside.

Or, and as in the case of the Area control units or Autonomous control units, who have the authority to control within CAS taking 5 miles or 5000 sep under a Radar Control service, Mil acft must do exactly as directed by ATC and ATC must achieve standard uncoordinated ICAO sep or an agreed lesser margin subject to verbal co-ordination of the civilian controller working the other traffic inside CAS.

Bearing in mind the status quo in the UK; i.e. limited airspace, high traffic densities, cross section of aircrew experience, and yet full radar coverage, the system for improving safety OCTA (class G) is a good one. Regardless of being IFR or VFR or having 2000hrs and doing 420 knots or 40 hours and doing 90 kts, you can get a radar service (free I think) and be just about guaranteed not to hit anyone else. OK, standard separation may not be achieved at all times, but then again any VFR aircarft can pass within a few hundred metres of you when your sighted by him/her anyway. A miss is after , all as good as a mile!

For anyone visiting the Uk its worth a visit to one of the busier Mil units just to see the sytem at work. Of course the civs also provide RAS and RIS OCTA when required, but I think their focus is more on the management of their stripboard and participating units inside their " controlled airspace". OCTA is after all In*ian territory and you need a little bit of co*boy in you to operate safely out there. Controlling is very reactive and wnen busy you need to bugger strip writing,get scanning, work out a resolution and keep talking!! "Avoiding action turn hard left heading.etc etc .... traffic....was etc etc With mulitiple aircraft on freq within 40 nms, travelling all different directions at up to 420kts plus, it can take some doing!! Time isnt always on your side.

DogGone:ok:

[Say Again, Over!]

I got it! :D

Thanks for the clarification gentlemen. I guess the difference would be, here in Canada, that you cannot operate in IMC without some kind of a clearance, or, to be more precise, a valid clearance limit in the event of lost comms.

What would be the procedures for someone on an RAS after a radio failure? Try to return to VMC? Or is a clearance limit issued as part of the RAS?

Thanks again, :ok:

SAO

[bookworm]

What would be the procedures for someone on an RAS after a radio failure? Try to return to VMC? Or is a clearance limit issued as part of the RAS?

Enroute in class G, no clearance is required or issued. Any instructions are advisory in nature. Unlike an IFR flight in controlled airspace, where a comms failure contingency plan is required so that ATC can continue to provide separation, the IFR flight outside controlled airspace can do what it likes anyway as no separation is guaranteed. The pilot will take whatever action necessary to make a safe landing from a terrain- and obstacle-avoidance point of view.

In most circumstances, the pilot is likely to try to return to and maintain VMC. If that is not possible, continuing in accordance with the original FPL and executing an IAP outside controlled airspace is the likely choice.

If the flight planned to enter controlled airspace before landing, all bets are off. In principle, the comms failure procedures allow the pilot in IMC to continue in accordance with the flight plan (if one has been filed) even if that means entering controlled airspace. In practice, I think most pilots would avoid that if at all possible.

[Say Again, Over!]

Thanks bookworm! Understood. :ok:

SAO