IFR or VFR?
 

Setting the scene:

3500 -RA SCT004 BKN006 OVC008

You want to depart in a fixed wing from an airfield with the above weather. You elect to depart VFR and immediately enter IMC on departure, climb to your desired altitude which is a common altitude flown in this congested airspace of the UK where further climb is limited by the TMA. As you have departed VFR, you are receiving no form of radar service even though good coverage and service is provided by two separate radar units located nearby.

Questions posed:

1: Is this departure legal under the VFR rules and do you consider these rules are clear, and understood fully by pilots or are they unduly confusing?

2: If it is considered legal, do you consider it sensible to depart in these conditions, fly IMC with no form of radar cover, and no way of avoiding other aircraft which may be in your path?

3: If the rules are understood and it is not considered sensible, what reasons would a pilot choose for not departing IFR? Is there a worry about route charges or something similar?

Discuss!


(edited for typos)

OK...

1 - if you're under 140kts then with 3k+ visibility I think it is legal. I guess the "I think" means that yes, the rules can be confusing, but the they are probably fine in most conditions - I think the confusion is for conditions far below what most PPLs or PPL/IMCs would fly in.

2 - Departure in these conditions is reasonable with an IR, bit daft with just an IMC (cloud conditions are well below the recommended minima for an IMC holder). I'm assuming that there's no icing or the aeroplane can cope with it. En route, well there's not going to be very much in the way of traffic flying in uncontrolled airspace in that weather and it's a big sky. I'd guess that the chances of a mid-air are much lower than other failures that could spoil your day (although I have no data to substantiate that).

3 - Dunno, ISTR that route charges could be involved.

1) I think it's legal to take off, but I'm not certain... but only if there are sufficient gaps in the "SCT004" layer for you to get high enough to satisfy the 500' rule. It is not legal to enter the clouds.

2) If you're departing VFR, then it's not legal to do what you're suggesting, because you're not allowed to enter cloud. If you're departing IFR, then it is legal. As for sensible, that would depend how busy the airspace was, and whether it is in controlled airspace. If it's in controlled airspace (even non-radar) then ATC will provide me with at least some separation. (Assuming Class D, they will separate me from other IFR aircraft only), so I see no problem with it.

If it's uncontrolled, then you have two choices. Option 1 is what you are describing, except that you would be IFR, not VFR. I would suggest that this is only safe in very quiet airspace. Option 2 is to depart VFR, level off below the clouds, and stay there until you get a radar service. Since not many private pilots fly in this type of weather, LARS stations are generally quiet so getting a radar service, assuming you're in area that's covered, won't be a problem.

3) Can't think of any reason for departing VFR in these conditions, unless, as I described above, you're planning on levelling off before getting radar service (which you can't do under IFR in these conditions because of the 1000' rule).

I think, though, that most of these problems answer themselves once you understand the difference between VFR and IFR in UK Class G airspace. Basically, you can switch between the two at will. There is no requirement to tell anyone which set of rules you are flying under at any given time. There is no requirement to be talking to anyone if you're IFR outside of controlled airspace. The only significant differences (apart from the obvious about flying in clouds and out of sight of the surface) are the 1000' rule and the requirement to fly at quadrantal levels if above 3000' when under IFR.

FFF
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Can one do an IFR departure from a small airfield with no ATC and no IAP? I don't think so, and this is why one would depart VFR.

Assuming an IMCR or IR pilot and an aircraft suitably equipped for flight in real IMC (i.e. not your typical self fly hire spamcan) there is nothing illegal about the scenario described, departing VFR and changing to IFR right away and asking for an RIS.

At say 500ft agl you will need to be very close to the radar unit to get RIS because they need both primary and secondary returns. In fact I recall something about radar units not providing a RIS below 1000ft or something like that.

I would ask the tower to call the radar unit so you takeoff with the squawk already set.

The only real danger (unless one gets into the "IMC without RIS flight is dangerous" argument, for which there is no supporting data) is that on engine failure one would have about 10 seconds to find a suitable field...

I have taken off in OVC003 but that was immediately over water, so no need to look for a field :O Then climbed to FL070 and still in IMC... but icing wasn't a problem there.

I disagree - I'm not aware of anything that would prevent you from doing this. In fact, you have to do it every time you leave a small airfield with no ATC at night.

FFF
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Under these conditions you can not depart VFR.

That is pretty clear from the regulations.

You can only fly in IFR outside CAS but there is no reason why you should not ask for a service from a nearby unit as soon as you find yourself in IMC.

If there is no unit around that can give you a service and you feel uncomfortable you would probably benefit from a revision of your decision making processes before your next flight as it means that you have taken off in rather cruddy weather from an airfield without an IAP.

Some would say that is not the cleverest thing to do if you are in a twin, most would say it was unclever in a single.

FD

Do you have any references for this? My understanding is that, as long as the gaps in the clouds are sufficient for you to get 500' from buildings, structures, vehicles, etc etc, there is no legal reason not to depart VFR (whether it's wise or not is a different matter). But I'm not certain of this, and if you can find anything to the contrary I'd be interested to read it.

FFF
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I faced almost exactly this situation yesterday, except that I would have called it an IFR departure. There was also an IAP (or several) at the departure field.

I didn't go, because I was worried about being above the freezing level and in cloud. Had the freezing level been higher (as it turned out it was, later on), I'd have gone. Legally, I'm sure.

It's probably in the UK AIM, but there's no index to that, and I rarely succeed in finding what I'm looking for in it (short of reading the whole pesky thing each time).

I've flown a lot of "IMC Rating IFR" in the UK, and ask for a RIS whenever I can get one. It's extremely rare for there to be anything else around in those circumstances, so the "big sky" theory protects me.

I also avoid routing over VORs (honeypots) or at round multiples of 500 feet, or at 2400 feet round the LTMA.

Not departing IFR? The only reason would be if you were in something over the magic weight limit, at which point you'd incur hefty Eurocontrol charges. So you depart VFR and avoid the charges, then change to IFR when airborne.

Keef -- I'm not sure you're right about avoiding IFR charges by making a VFR departure (assuming your aircraft is heavy enough to incur IFR charges). My understanding is that IFR charges are incurrred if ANY part of the flight is IFR.

Of course, if nobody knows you're IFR, then you won't be charged.

But the whole point is that you go IFR either because your weather is worse than the VFR minima or because you chose it for safety/convenience. In either case you chose so should be prepared to pay (without opening the avgas duty etc cans of worms or the 'but I got no service' argument ;-)) ).

AA.

Just to recap (for myself:D)......UK VFR minima in class G (assuming class G) specify minimums of 1500m vis, clear of cloud and in sight of surface below 3000' and 140Kts. Above 3000' its 5km vis, 1500m from cloud and 1000' vertical seperation from cloud....

So i suppose in theory you could depart VFR and remain "clear of cloud and in sight of the surface" and not break the 500 or 1500' rule.

As mentioned, switching between VFR and IFR outside CAS in the UK is a sinch, you just do it. Depending on why I wanted to fly would determing whether I depart IFR VFR or at all. If travelling A to B, I would file an IFR flight plan (icing permitting) and depart IFR. If I was just going for a jolly, I wouldn't go, as "Max VFR" (named after a friend of mine, who specialized in dodgey VFR :D) is highly dangerous in my book.

Departing IFR, and filing an IFR flight plan would probably help in getting a RAS, though I am not sure on how the system works with regards to routing IFR flight plans. Probably a LARS unit wouldn't get a copy. Every time I've pre-filed though, it certainly seems easier to get a RAS. Also pre-filing seems to help getting airspace transitions, and you won't get a routing change unless you are inside CAS and they want to change your route for some reason. ATC cannot route you through un CAS, and to enter CAS you'd have to have an IR and fly the airways. When transitioning Class D airspace, you'll be provided Radar Control service, where you're essentially given vectors to fly, so no big deal there.

Probably the worst thing you could do in this situation is depart VFR, then switch to IFR once airborne especially if you then want to negotiate CAS transitions. At least when you pre-file, someone knows you're going to be there.....

Cheers
EA

PS Depating a field with no IAP is no problem. Just remember you may not get back in again in an emergency, so it could be considered un wise unless you have an alternate nearby, or have made up your own GPS procedure :D

AA,

That is correct but practice learns that this is an area where they usually don't send a bill.

EA,

Thank you for chapter and verse, so FFF, there you have it, in the scenario depicted I think you will be therefore be struggling to stay VMC.

Not my idea of fun but I know there are people about who would happily launch into something like that.

FD

Pure co-incidence. Flight Plan filing has nothing to do with service received. If you say you're IFR you can get a RAS, but only then. Flight Plans (in the UK) only go to the centre's if you've routed airways, airfields of departure and destination, and anyone else that you may have addressed it to - though as most pilots leave the addressing to ATC then it normally only goes to who I've said above.

Quote:

3500 -RA SCT004 BKN006 OVC008

Quote

2 - Departure in these conditions is reasonable with an IR, bit daft with just an IMC (cloud conditions are well below the recommended minima for an IMC holder).

Why are the cloud conditions well below the minima for an IMC holder?
It depends on what approach systems are available. An ILS or NDB approach with a DH/MDH of 400' or less can be legitimately attempted by an IMC holder in these conditions. For the purposes of takeoff in a single CAP507 states that a cloud base of 1000' agl is the public transport minima but also says that takeoff with less than 600' cloudbase is not recommended.

Given the met. conditions stated, we would not issue a VFR clearance to fixed wing aircraft in Class D airspace.


VA

I did say recommended minima. With the weather given you could be flying into cloud at 400 feet, and "takeoff with less than 600' cloudbase is not recommended". Thom suggests that an average IMC holder should use considerably higher minima than those recommended.

I appreciate that the IMC covers a multitude of abilities - there's a huge difference between an IMC issued on the basis of an FAA IR and a bog-standard PPL/IMC like me - and there are IMC holders who could depart. It would probably be a bit daft for most of us. :)

Although I don't know who Woss.... is, there is a paranoid side of me that is thinking that it is I who am being targetted by this thread, as I departed Biggin in exactly that METAR yesterday.

I would agree with much of what has been said, pointing out that I have an IR, the aircraft is a de-iced twin (though the freezing level yesterday was 4000'), there is an IAP and ATC at Biggin and that the weather at Farnborough was suitable for vanilla PPL VFR.

Keef is quite right (he knows me well) that the motivation for departing VFR is to avoiding route charges. I am perfectly happy to pay charges in a controlled environment (such as airways) (though I still don't understand why I, in my Aztec, should and a Seneca, or indeed Arrow, shouldn't) but I am damned if I will willingly pay for a service outside regulated airspace which is voluntary and sporadic.

W

EVO Actually the cloudbase is 600' in the example. Definition of cloudbase being 'Lowest layer of cloud of BKN or greater, or first layer of cloud if nothing greater than SCT'. If the 'SCT' amount was only 3 oktas (SCT being 3 or 4) then it's quite concievable that you could avoid it quite happily.

Nothing wrong with the VFR departure as quoted and then redeclaring yourself IFR on departure. As class 'G' airspace does not require any form of IFR clearance then it's up to the pilot to fly iaw the Instrument Flight Rules, none of which require any form of ATC intervention unless requested by the pilot. It's like everything in flying - you make your own risk assesment and fly accordingly. If it was WCollins in this scenario then I don't have a problem with it knowing the man, the experience and the equipment involved, as well as the airspace. I would have quite happily done the same.

Woss goin on..? asks a number of related but distinct questions. First the legality issues:

To enter IMC requires (by definition) the flight to be conducted, at that point, under IFR. There is no reason why a flight should not change from being a VFR flight to an IFR flight at any point, from moments after take-off to moments before landing.

In controlled airspace, a clearance is required for IFR flight. Therefore the scenario described would be illegal, unless approved in advance by ATC in which case it would almost certainly be pointless.

Outside controlled airspace, a clearance is not required for IFR flight. Thus it would be perfectly legal to switch from VFR to IFR when required. The only wrinkle might be if the airport of departure had ATC, in which case the controller has the right to instruct the aircraft to maintain VFR within the ATZ. In those circumstances it would be necessary for the pilot to remain in VMC until outside the ATZ.

Now for the is-it-sensible? issue:

There seems to be a level of confusion about aircraft separation implicit in the question.

On the assumption that the flight is being conducted outside controlled airspace, there is no reason to believe that the flight would be better separated from other aircraft simply by virtue of being IFR rather than VFR. If radar is available, a radar service may (and probably should) be offered to VFR flights as well as IFR flights. If radar is not available, the IFR flight is separated only from other participating IFR flights. If there are none, or the pilot of the departing flight is aware of the other IFR flights known to ATC, then that minimal separtion service is no better than what the pilot can achieve with common sense.

Then the motive:

I would imagine that might be the issue. Charges are applied to aircraft between 2 and 5.7 tons if any part of the flight is conducted under IFR, regardless of the service provided. If a flight departs VFR, it is less likely to find its way onto Eurocontrol's system.

Finally
The complexity of regulations often go with the flexibility they offer. In this case a great deal of flexibility is offered compared with, for example, the German practice of simply banning IFR outside controlled airspace. If the complexity of the UK system troubles anyone, there is no reason why they should not simply decline to fly IFR outside controlled airspace.

CAAFU requires IIRC 1800m and 1000ft for exam flights in a single for an IR.

FD

If concerned about traffic & are OCTA then make a broadcast: Callsign/type, position, altitude & intention/next position & estimate.

That at least gives a 'heads up' to anyone nearby & on the freq. You can then coordinate your own separation.

Tinstaafl

And what frequency would you propose making this broadcast on?

although it may be legal, it sounds like very bad airmanship to do such a thing and very dangerous. I think it would be very foolish to fly in IMC with no radar cover.

Well it amazes me how much disinformation one gets from instructors.

I have been categorically told that an IFR departure cannot be done unless the ATCO is qualified to give it. You get it read to you just before lining up, you then read it back and say you are ready for departure. I never knew that you can depart IFR without talking to anybody. I know you can fly en-route IFR of course.

At my airfield, which is licensed after say 0830, you can depart VFR after 0800 but cannot do an IFR departure until 0830. I don't know if this is related to it being licensed, or related to a suitably qualified ATCO turning up at 0830.

Re the IMC Rating stuff, I don't want to drag out the old argument but I always succumb to temptation :O What is the difference between an IMCR pilot and an IR pilot, with the same currency (or lack of) in IMC and on type, in the same aircraft suitable for the job? The difference is that the IR one has sat a load of exams, perhaps many years ago. There is a lot of expired IMCR pilots but there is also a lot of expired IRs (including great many instructors).

Rupert S

Rather a sweeping statement if you don't mind me saying. There are times and places where you have to fly in IMC without a radar service. Outside of CAS this is a fact and there's nothing you can do about it. That's why there's such things as quadrantal / semi-circular rules - to reduce the risk. It's like I said earlier - you risk assess it and act in accordance with that assessment. It's neither good nor bad airmanship - just a fact of life.

IO540

Your instructor is technically right. Take a look at the UK AIP (AD1.3 is the relevant section). There it states what flight rules are applicable for each airfield, and any caveats that may apply. So - you can only depart and arrive VFR at some (mainly A/G / AFIS type airfields). The grey area is - at which point can you declare yourself en-rte and therefore go IFR ;) To be quite honest this table should really be re-labelled VMC/IMC because, as others have said, what about night flying, which is technically IFR (but which uses the 'clear of cloud and in sight of the surface' caveats of IFR at airfields which are not listed as IFR airfields!)

This chesnut comes up with boring regularity. Just have a look at the number of aircraft which have collided in the open FIR/Class G when in cloud in the last 50 years (= 0, to save you the trouble) compared to the number in VMC, or the number in controlled airspace and you will realise that IMC in uncontrolled airspace is the only safe place to be.

So, can I be excused from being foolish and dangerous please :O

W

Chilli Monster,
Perhaps I was a bit hastey in my reply - I should have said that one would be ill advised to fly in such conditions without a radar service if one was availible especially in congested areas (which I would imagine this thread is referring to).

If there's a radar service, and you're in IMC, using it is a good idea. It's not a bad idea in VMC either. I often get VFR traffic pointed out to me by LARS units. You can look and look and still not see. It's the low-down dark-coloured ones I have trouble spotting.

But I've flown (and been flown) many times under IFR in IMC in open FIR, with no radar or anything else, and wasn't worried. It's a big sky! Just avoid the honeypots.

Chilli Monster

Thank you for confirming what I thought, and my apologies to those instructors who told me what I said :O Mind you I still have to deal with the CFI (ATPL) who told me you can saturate a VOR (a VOR, not a DME) if you tune too many receivers to it...

I would transit to IFR as the zone boundary i.e. pretty well right away. But one won't get an RIS if below the minimum authorised RIS level for that radar unit, so in the conditions described one would be IMC by the time one gets any cover.

Except for the engine failure scenario (which assuming one can actually fly in IMC is statistically the only real risk) I would be quite happy to depart in those conditions - IF the destination and alternate are both clear.

What I don't know is whether the PILOT himself is able to phone the radar unit before departure, and get a squawk allocated.

We don't lay down a minimum altitude for RIS, only RAS. At lower levels away from the radar head (1000ft per 10nm is a good rule of thumb for lower limits of cover) the service will be limited and the reason for limitation will be explained in the 'verbal contract' of service.
Nothing to stop you - but I wouldn't bother. There are many standing agreements between adjacent units regarding the verification and validation of squawks. You could end up in a position where you get airborne, wearing this pre given squawk, but your mode 'C' is out. Adjoining unit sees you wearing another units squawk, take it to be validated and verified (which it hasn't been) and promptly has an airmiss with you because the mode 'C' isn't what it appears to be.

Just call as soon as possible.

In response to one of the original questions, one reason a pilot may prefer to depart on a VFR clearance rather than an IFR clearance, is to avoid ATC delay.

As an IFR departure, ATC would be required to separate you from other IFR traffic they are working as an Approach unit. Due to requirements of separation, then (particularly in a Procedural ATC environment), the delays can soon mount. A VFR departure does not have the requirement to be separated by ATC, so tend not to be delayed by waiting at the holding point waiting for separation to be acheived, as an IFR departure may be.

Now whether it is desirable on safety grounds for aircraft to depart as VFR in such conditions, is a different question. It certainly doesn't fill ATC with a warm glow of 'everything is all right' when such VFR departures immediately enter IMC on departure as they have not until then been required to separate that traffic from the other known IFR traffic. Apart from the effect on the separation of the (now IFR) departure, it may have also seriously reduced the separation established between other IFR flights that ATC is responsible for separating, but hadn't been expecting to have to separate from the VFR departure.

4

This discussion brings to my mind the fact that when I did my IMC flight test the examiner had me take off under the hood. I put the hood on at the departure hold and he did the taxi on to the threshold, at which point he handed over to me. It was a bit of a shock at the time because I'd never tried it with my instructor.

Is this a normal procedure for an IMC skills test? Any examiners care to comment on it?

Never heard that one before.

FD

Did it for the FAA IR, though don't think it is required for the flight test.

Believe it is meant to be part of the training ("instrument Takeoff"), the idea being to

"•Instrument takeoff provides proficiency and confidence necessary to execute instrument departures under conditions of low visibility and rain
•Prepares student for rapid change of flight from visual flight into IMC"

Cheers
EA

I'd have thought that it would do quite the opposite. The transition from a visual take-off to instruments in very poor visibility is a difficult skill to learn and something that is very dangerous indeed if you get it wrong, particularly with a simultaneous engine failure, and I would have thought that practising and demonstrating that skill was more important than doing the whole takeoff run on instruments.

Incidentally, when I did my (CAA) IR training in the early 80's I was expected to do a landing entirely on instruments, not for the test but during training. The particular instructor, Dai Heather Hayes, wanted us to realise that if push came to shove it was more practical to land in zero vis than to eventually plough a furrow somewhere under the hold when the fuel ran out.

W

Ah, Yes. Good old Dai, he did my CPLA checkride!

Forever practical. Far better to crash near the fire engines :ok:

Is he still around at Perth?

BTW, sometimes we are obliged to fly IFR in UK without a proper Radar service as there isn't always anyone to obtain a service from! Not ideal. We do have TCAS which helps a little provided others use their transponder and radios sensibly and fly quadrantals. Below the London TMA is a problem, no chance of a quadrantal but normally a radar service is available. But it seems there are an awful lot of aircraft out there NOT using Mode C in the London area...wonder why?

I can think of a number of reasons:

No Mode C installed (quite common)
Mode C installed but u/s (very common)
Lack of training
Wish not to self incriminate

W

TAKING OFF UNDER THIS FORECAST
 

Er excuse me chaps, don't want to interrupt but my ATPL Air Law course taught me that......



VFR flights shall not take off or land at an aerodrome within a CTZ, ATZ or traffic pattern :

a) when cloud ceiling is less than 1500ft or;

b) when GROUND vis is less than 5000m.

You may be Authorised to take off and land under more marginal conditions but this requires an SVFR clearance from an ATCU.

I don't remember the figures on the original post exactly but a vis of about 3500 was quoted with various cloud layers at 400-800ft.

This does not represent a VFRable departure as far as I can tell. The mere fact you immediately wish call the flight IFR just after takeoff tells you the full story!

Imagine this scenario....... you had engine failure/problems at say 1500ft. you are probably 2-3 mins after takeoff in a low winged single with 8-10:1 glide ratio........what would you do?

Think about it.

There is a blanket of cloud below you (ovc800). Any Nav aids or a friendy ATC with radar to vector you back, that is if you have time to make the radio call.

Thankfully this forum allows pilots a chance to find out about these issues and many others. I may well be right off the mark with my own knowledge and someone more senior may be able to put me straight, but in my book caution is the best option.

Yes some of these VFR/IFR rules are confusing and can ofetn be interpreted in many different ways and I think that is a major problem both for pilots and the regulatory authorites ie JAA/CAA.

The AIPs and ANOs are not exactly easy reading and finding anything for reference purposes can take ages. In Australia the CASA (OZ CAA) produce a DAY VFR guide which includes virtually all the relevant air law for VFR flying. It even has a glossary and an index with page numbers for you to look thinks up 'at a glance'.

Maybe some clarification of what a VFR departure is needs doing by the CAA.

What do you think?

regards

Tropo

Tropo

You may be right, but I have scanned ANO and Rules of the Air and can't see such a regulation. Bookworm where are you? :oh:

I have looked up Fairoaks in the AIP and there are specific local limitations there that VFR aircraft must maintain surface contact in a minimum vis of 3km. Can I respectfully suggest that this limitation would not be specific to Fairoaks if it were a general rule?

I wonder what it was that your Air Law paper was getting at? Maybe to do with PT Ops? Actually there are stipulations in the ANO about PT, but they don't seem to include the ones you mention.

Finally, I can't really see that your admonition that it is not safe for a single to take off in poor conditions would be made any different for an IFR departure. Woss' point was about the choice of IFR and VFR. Your point is (if I understand) that it is not safe for a single to operate in IMC at all. There is no doubt that singles are permitted to take off in IMC under IFR, whatever your (and indeed my) opinion of the advisedness of doing that.

Forgive me if I have misunderstood.

W

WCollins / ShyTorque - Dai is certainly still a more or less permanent fixture at Perth!! Around 80% of the times I go there to fly, he's there!! He still has his Pitts; I have never flown with him, but a couple of the guys in my club have and reckon that it's the best hours instruction they've ever had! He certainly teaches pragmatic flying - not just reeling out the numbers, but tries to convey a deeper understanding of what the aircraft's up to.

WCollins,

Don't see why the first 3 should be more common around London.... ;)

Number 4 seems favourite :rolleyes: