Departing VFR in fog
Sub Judice Angel Lovegod
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Departing VFR in fog
The SATCO of a controlled airfield which lies outside Controlled Airspace recently commented (in another place) that they get a lot of VFR departures in IMC (he particularly mentioned fog) from the >2T brigade.
I asked him whether he thought that there were any benefits to departing IFR in shallow fog, where the entire flight was outside controlled airspace.
I haven't had a response, presumably because he has been away, but can anyone here help?
I am thinking of the Oxford/Cranfield/Biggin/Filton world, in, say, R350, with tops at around 150' and no other weather. There is a take-off alternate and both destination and alternate are CAVOK.
I asked him whether he thought that there were any benefits to departing IFR in shallow fog, where the entire flight was outside controlled airspace.
I haven't had a response, presumably because he has been away, but can anyone here help?
I am thinking of the Oxford/Cranfield/Biggin/Filton world, in, say, R350, with tops at around 150' and no other weather. There is a take-off alternate and both destination and alternate are CAVOK.
But Timothy, if you don't depart IFR you don't get that warm fuzzy feeling from knowing that you've contributed to the NATS Fund for the UpKeep and Taking-care of IT... no hang on that can't be right the acronym is supposed to be FDPS... 
niknak
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Timothy
For departures, it's entirely down to you as the PIC and whatever your CAA approved company op's manual says, or failing that, the restrictions that may pertain to your individual licence or ratings for the aeroplane.
As ATCOs or the Airport Authority, we cannot stop you departing because the RVR is below a certain level, the decision is yours.
It's always down to you to fly in accordance with your licence, and although we may report the facts if you do look as though you are doing something that is not safe, we can't stop you doing it - I have no desire to be a policeman, but I wonder how many lives would have been saved if we could just delay someone for that critical short while.
What you must bear in mind is that the CAA have issued each airfield in the UK where there is an instrument approach procedeure, with RVR minima for each type of approach. i.e if you want to do an NDB approach at Norwich and the with a CAA approach minima of RVR 900m and the RVR is 1000m, you cannot legally commence the approach.
As an experienced pilot, you will know that the UK weather is very fickle, and what can be CAVOK at the alternate can soon become fog and crap.
For departures, it's entirely down to you as the PIC and whatever your CAA approved company op's manual says, or failing that, the restrictions that may pertain to your individual licence or ratings for the aeroplane.
As ATCOs or the Airport Authority, we cannot stop you departing because the RVR is below a certain level, the decision is yours.
It's always down to you to fly in accordance with your licence, and although we may report the facts if you do look as though you are doing something that is not safe, we can't stop you doing it - I have no desire to be a policeman, but I wonder how many lives would have been saved if we could just delay someone for that critical short while.
What you must bear in mind is that the CAA have issued each airfield in the UK where there is an instrument approach procedeure, with RVR minima for each type of approach. i.e if you want to do an NDB approach at Norwich and the with a CAA approach minima of RVR 900m and the RVR is 1000m, you cannot legally commence the approach.
As an experienced pilot, you will know that the UK weather is very fickle, and what can be CAVOK at the alternate can soon become fog and crap.
Sub Judice Angel Lovegod
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niknak
Thanks, but I am not really asking for a statement of the legal position, which I think I understand, nor am I discussing the arrival weather, which might be a weather system away in the S of France, I am asking specifically if anyone can think why an IFR departure in shallow fog would be better (in any terms; safety, regulation, economy, anything) than a VFR departure.
Thanks, but I am not really asking for a statement of the legal position, which I think I understand, nor am I discussing the arrival weather, which might be a weather system away in the S of France, I am asking specifically if anyone can think why an IFR departure in shallow fog would be better (in any terms; safety, regulation, economy, anything) than a VFR departure.
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There is no reason why the IFR departure would be better.
If you wanted to depart VFR that's up to you, as it's up to you to fly within the limitations of your licence. The thing is if there were other departures at the time then no doubt the ATC unit concerned would separate you from other, IFR traffic. They would however probably appreciate a quick call when you were above the fog layer and in the clear (it's a two way street after all).
I know where you're coming from and I'm completely in agreement - why should you pay route charges for the whole flight when you're IMC for 30 seconds and VMC for the rest.
If you wanted to depart VFR that's up to you, as it's up to you to fly within the limitations of your licence. The thing is if there were other departures at the time then no doubt the ATC unit concerned would separate you from other, IFR traffic. They would however probably appreciate a quick call when you were above the fog layer and in the clear (it's a two way street after all).
I know where you're coming from and I'm completely in agreement - why should you pay route charges for the whole flight when you're IMC for 30 seconds and VMC for the rest.
Sub Judice Angel Lovegod
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Outside controlled airspace VFR flight shall always adhere to VFR restrictions i class G (or F) airspace, e.g. clear of clouds, flying visibility etc.
Ironically, the potentially illegal bit would be once you pop out, but are still below 1000', in infinite vis.
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Timothy,
For you at Biggin, departing IFR may cost more but Thames are obliged to give a radar service to an IFR departure (if we can't we have to tell you before you depart). May only be a Limited RIS.
The only other plus I can think of is in case you wanted to divert back immediately which means we could vector you at min sector altitude.
For you at Biggin, departing IFR may cost more but Thames are obliged to give a radar service to an IFR departure (if we can't we have to tell you before you depart). May only be a Limited RIS.
The only other plus I can think of is in case you wanted to divert back immediately which means we could vector you at min sector altitude.
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To fly VFR you have to have the ground in sight.
In the former case, if the visibility is 250m (a reasonable bet for R350) then you could climb to 750' and still be in sight of the surface. I am talking about 150' of shallow fog.
Alan, if I had to go back with an engine fire you would look after me on a Mayday squawk, IFR or VFR wouldn't you? Pretty please?
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Dewdrop
Common misconception. Those of us with the relevant extra ratings do not have to have the ground in sight.
AlanM
Like Timothy I wouldn't be upset about not having a radar service for the first 300' of climb if I was in the knowledge that above that level it's going to be unlimited vis and no cloud above. The conditions themselves are naturally going to cut down the number of aircraft out anyway. I've departed a non-radar airfield under similar conditions in the same type that Timothy operates - the rate of climb of the aircraft (1000fpm+) makes the option perfectly acceptable.
To fly VFR you have to have the ground in sight,
AlanM
Like Timothy I wouldn't be upset about not having a radar service for the first 300' of climb if I was in the knowledge that above that level it's going to be unlimited vis and no cloud above. The conditions themselves are naturally going to cut down the number of aircraft out anyway. I've departed a non-radar airfield under similar conditions in the same type that Timothy operates - the rate of climb of the aircraft (1000fpm+) makes the option perfectly acceptable.
Sub Judice Angel Lovegod
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To fly VFR you have to have the ground in sight
If you are not instrument-rated this thread is not really relevant to you.
Sub Judice Angel Lovegod
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Minimum visibility for VFR is 1500m in class f or g. Fog is defined by its visibility being below 1000m. So how can you be VFR in Fog?
One of the definitions of VMC (and hence the availability of VFR in Class G) is "Clear of cloud, in sight of the surface" provided the IAS is less than 140kts.
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CM
I have no problem with you going VFR matey!! As an ATCO we don't police what you do outside controlled airspace to that extent.
Timothy - of course we would look after you (as we always do
)
But if you had a problem when there was patchy fog around and you WEREN'T visual it may take a while to get you over to us and vectored back (obviously you would be the priority traffic).
On the Biggin Hill scenario, what is the difference in price for a VFR/IFR (radar monitored) departure? You have oodles more experience and hours than me so only you can decide what is best.
Have fun (and watch out for the Epsom traffic!!)
I have no problem with you going VFR matey!! As an ATCO we don't police what you do outside controlled airspace to that extent.
Timothy - of course we would look after you (as we always do
)But if you had a problem when there was patchy fog around and you WEREN'T visual it may take a while to get you over to us and vectored back (obviously you would be the priority traffic).
On the Biggin Hill scenario, what is the difference in price for a VFR/IFR (radar monitored) departure? You have oodles more experience and hours than me so only you can decide what is best.
Have fun (and watch out for the Epsom traffic!!)
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Eh What !! I nip under my rock for a couple of days and look what happens.
Timothy, I do not want to get into legalities on this issue but for those not wishing to thumb through the books this is what the Rules of the Air has to say.
Flight outside controlled airspace
Rule 26
(1) An aircraft flying outside controlled airspace at or above flight level 100 shall remain at least 1500 metres horizontally and 1000 feet vertically away from cloud and in a flight visibility of at least 8 km.
(2)
(a) Subject to sub-paragraph (b), an aircraft flying outside controlled airspace below flight level 100 shall remain at least 1500 metres horizontally and 1000 feet vertically away from cloud and in a flight visibility of at least 5 km.
(b) Sub-paragraph (a) shall be deemed to be complied with if:
(i) the aircraft is flying at or below 3000 feet above mean sea level and remains clear of cloud and in sight of the surface and in a flight visibility of at least 5 km;
(ii) the aircraft, other than a helicopter, is flying at or below 3000 feet above mean sea level at a speed which according to its air speed indicator is 140 knots or less and remains clear of cloud and in sight of the surface and in flight visibility of at least 1500 metres; or
(iii) in the case of a helicopter the helicopter is flying at or below 3000 feet above mean sea level flying at a speed, which having regard to the visibility is reasonable, and remains clear of cloud and in sight of the surface.
Now in my thinking the lowest form of VFR outside CAS is in sub-para ii) which requires a flight vis of 1500 metres. So technically can you take off VFR in something less than that?
As other ATCOs have posted we are not policemen and I am not going to go into mega form filling on every occasion someone leaps off VFR in any sort of crud. I have been tempted to do so myself sometimes but the thought of what happens in a single engine aeroplane if it all go's quiet after lift off tends to keep me drinking coffee til things improve.
Things get more interesting when someone departs VFR in the murk and is then NOT on top of cloud. That is more commonplace around Biggin than the shallow fog scenario. Now I have launched someone VFR who is now IFR and I have certain added responsibilities as an ATCO, like ringing up AlanM and appologising for the pop-up IFR
Timothy, I do not want to get into legalities on this issue but for those not wishing to thumb through the books this is what the Rules of the Air has to say.
Flight outside controlled airspace
Rule 26
(1) An aircraft flying outside controlled airspace at or above flight level 100 shall remain at least 1500 metres horizontally and 1000 feet vertically away from cloud and in a flight visibility of at least 8 km.
(2)
(a) Subject to sub-paragraph (b), an aircraft flying outside controlled airspace below flight level 100 shall remain at least 1500 metres horizontally and 1000 feet vertically away from cloud and in a flight visibility of at least 5 km.
(b) Sub-paragraph (a) shall be deemed to be complied with if:
(i) the aircraft is flying at or below 3000 feet above mean sea level and remains clear of cloud and in sight of the surface and in a flight visibility of at least 5 km;
(ii) the aircraft, other than a helicopter, is flying at or below 3000 feet above mean sea level at a speed which according to its air speed indicator is 140 knots or less and remains clear of cloud and in sight of the surface and in flight visibility of at least 1500 metres; or
(iii) in the case of a helicopter the helicopter is flying at or below 3000 feet above mean sea level flying at a speed, which having regard to the visibility is reasonable, and remains clear of cloud and in sight of the surface.
Now in my thinking the lowest form of VFR outside CAS is in sub-para ii) which requires a flight vis of 1500 metres. So technically can you take off VFR in something less than that?
As other ATCOs have posted we are not policemen and I am not going to go into mega form filling on every occasion someone leaps off VFR in any sort of crud. I have been tempted to do so myself sometimes but the thought of what happens in a single engine aeroplane if it all go's quiet after lift off tends to keep me drinking coffee til things improve.
Things get more interesting when someone departs VFR in the murk and is then NOT on top of cloud. That is more commonplace around Biggin than the shallow fog scenario. Now I have launched someone VFR who is now IFR and I have certain added responsibilities as an ATCO, like ringing up AlanM and appologising for the pop-up IFR
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That's what I was getting at SATCO, so unless I have misunderstood, you cannot legally depart VFR in any circumstances where visibility is less than 1500m, regardless of your licence limitations; can you?
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Ah - but the in flight vis is different to the reported vis - so techincally yes! I know that the reported met vis is the lowest seen, but you could judge it to be legal (if departing outside CAS)
Similar as an airfield in a Control Zone - you have to have the correct met criteria to take off and land. However, only you can say what the in flight weather is where you are so a transit is allowed (and choice of VFR/SVFR!!!)
(did you get the PM I sent you SATCO KB re: LCY fun day!!?!?)
Similar as an airfield in a Control Zone - you have to have the correct met criteria to take off and land. However, only you can say what the in flight weather is where you are so a transit is allowed (and choice of VFR/SVFR!!!)
(did you get the PM I sent you SATCO KB re: LCY fun day!!?!?)
I don't think that there's any doubt that a departure in fog (< 1000m vis) is not VFR. The more interesting point is what operation benefit being IFR would confer.
The value of departing IFR in class G in good VMC is very limited: ATC provide separation from other participating IFR traffic, though most of the traffic about is likely to be VFR or non-participating.
Departing IFR with 8/8 ST/SC base 500ft tops 5000ft in a vis of 3000 m has rather more value. You probably won't see the traffic that you're likely to hit, thus having ATC separate you from other arrivals and departures while you're within, say, 15 miles of the field is worth having.
But departing IFR in shallow fog? The only thing you're likely to hit that you don't have the opportunity of seeing for yourself is someone attempting to use the runway at the same time. But separation in using the runway is part of the good ol' vanilla aerodrome control service provided to VFR flights too. Being IFR rather than VFR is, from an operational point of view, pretty much valueless.
That's what I understood as the point of Timothy's initial question, though I think some misunderstanding has cropped up as to whether it's legal to depart VFR in fog (by which I mean a vis forward from the cockpit of < 1000m). It's definitely not legal. It's just that it doesn't appear to do any harm to anyone except NATS shareholders...
The value of departing IFR in class G in good VMC is very limited: ATC provide separation from other participating IFR traffic, though most of the traffic about is likely to be VFR or non-participating.
Departing IFR with 8/8 ST/SC base 500ft tops 5000ft in a vis of 3000 m has rather more value. You probably won't see the traffic that you're likely to hit, thus having ATC separate you from other arrivals and departures while you're within, say, 15 miles of the field is worth having.
But departing IFR in shallow fog? The only thing you're likely to hit that you don't have the opportunity of seeing for yourself is someone attempting to use the runway at the same time. But separation in using the runway is part of the good ol' vanilla aerodrome control service provided to VFR flights too. Being IFR rather than VFR is, from an operational point of view, pretty much valueless.
That's what I understood as the point of Timothy's initial question, though I think some misunderstanding has cropped up as to whether it's legal to depart VFR in fog (by which I mean a vis forward from the cockpit of < 1000m). It's definitely not legal. It's just that it doesn't appear to do any harm to anyone except NATS shareholders...
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It's just that it doesn't appear to do any harm to anyone except NATS shareholders...
(don't forget that the London/London City Zones are PPR today and tomorrow due to the Epsom Derby - as they will be during Ascot week) More details in the AIC.
Epsom Supp AIC Entry
Ascot Supp AIC Entry