Flying over fog...

[Monocock]

I should know this but I don't.

What distance of fog can a PPL legally overfly? I accept that the sensible side of this varies with height and that 1 mile of fog when at 3,000 feet is no issue compared to 5 miles at 500 feet.

I was met with a big white blanket today and teetered on the edge until sense kicked in and I abandoned.

Whilst driving where I had to go to instead, I wondered how much smaller that blanket would have been fro me to have decided to go for it.

I think had I been 10 years younger without wife and kids I would have gone for it. Having spent an hour stationary on the A34 I now wish I had!

Sorry if this has been asked before.

[IO540]

Never seen the UK CAA "in sight of surface" requirement defined.

[cadaha]

according to vfr/vmc rules

Starting point for VFR is min flight vis 8km, min distance from cloud 1000ft vertically and 1500ft horizontally.

But:

Below FL100 Class D, E, F & G
Vis 5km, 1500m and 1000ft from cloud.

At or below 3000ft amsl Class D & E
Vis 5km, 1500m and 1000ft from cloud.
if 140knts or less Vis 5km, Clear or Cloud, in sight of surface.

At or below 3000ft amsl Class F & G
Vis 5km, Clear or Cloud, in sight of surface.

And isn't Fog a really Low level Cloud???

[IO540]

Not sure the above is relevant. Is surface fog a legal cloud, anyway?

It's also wrong, although I don't have the books handy; a UK PPL can fly down to 3000m vis and down to the ICAO VMC of 1500m if he has an IMCR or IR.

All the stuff about a specific distance clear of cloud is silly; nobody can remember the rules, nobody enforces it and the distance is impossible to estimate.

[2Donkeys]

I think that the question was really aimed at getting some clarity on "in sight of the surface". This is not a limitation of the UK definition of VMC, so much of this thread is misplaced. Rather the concept is a PPL licence limitation removed if you hold either an IMC rating or IR.

So far as I am aware, there is no definition of "in sight of surface" contained within the usual reference sources.

To fulfil the spirit of law you might argue that the "surface" you can "see" should be sufficiently close and sufficiently large that you could glide down onto it without going IMC, should the need arise.

That definition is my own, make of it what you will.

2D

[cadaha]

look at AIP ENR 6-1-4-1, it gives the table for ATS Airspace Classifications with VMC Minima for each Airspace. The question did not mention IMC just PPL and since most PPLs are not IMC qualified I just stated what was in the Trevor Thom Manual for Air Law.

One question, if there is fog and the conditions are below VMC minima can you fly with IMC rating or is it IFR and you have to file an IFR flight plan, then if conditions improve cancel the IFR plan and go to VFR? Also do you have to have a full IR rating to file and IFR Flight Plan? :hmm:

[2Donkeys]

Cadaha

I think, in the nicest possible way, you may need to do a little more book work.

2d

[rustle]

To fulfil the spirit of law you might argue that the "surface" you can "see" should be sufficiently close and sufficiently large that you could glide down onto it without going IMC, should the need arise.Rule 5 (glide clear) for fog? Seems sensible, especially if you can see the extent of it...

[FlyingForFun]

Hmm.

The question that was asked was what was legal. I don't know of any legal requirement to be able to glide clear of fog. Rules about maintaining a given distance from cloud aren't relevant if you're sufficiently far above the fog or sufficiently low that the rules don't apply.

The only law I can think of that's relelvant is that you must be "in sight of the surface". And, from a legal point of view, surely that's all that's required - to be in sight of the surface? Doesn't matter what bit of surface it is, if you can see it, you're legal.

As is so often the case, though, what's legal and what's safe aren't necessarily the same. There's the ability to glide safely(but not if you're VFR in a twin without an IMC rating or IR). And there's the ability to navigate safely. And probably some other safety issues which aren't actually covered by the law but which are common sense.

FFF
----------------

[C-dog]

In sight of the surface is the key.

Think slant angle. If you can see the surface then in most cases you can make that surface unless:

a) the surface is high ground beyond the fog
b) you're flying a winged brick :O

I've turned back more than once on encountering the local east coast haar

[cadaha]

2d
I think, in the nicest possible way, you may need to do a little more book work.

Am doing:O

Great place for learning this forum is

[IO540]

dont descend through it without IR or being certain of position

I've binned my last copy of Loop but I sincerely hope they didn't write THAT !

If they did, I will light the BBQ with it without opening it :O

[Jucky]

Regardless of the legalities, good airmanship would dictate that it is not a good idea to fly over fog in a SEP. What happens if you have an engine failure?

[DubTrub]

It's fantastic flying over fog. What is defined as the surface?

http://www.dubtrub.freeuk.com/LM032.jpg

Power towers?

http://www.dubtrub.freeuk.com/LM034.jpg

The hills in the background?

http://www.dubtrub.freeuk.com/LM036.jpg

Just loverley!!! Certain precautions need taking, but sometimes risks are worth taking, as long as one knows that a landing airfield within range is available.

And where does the "in sight of cloud, clear of the surface" rule become invoked?:rolleyes:

[360BakTrak]

Fantastic pictures:ok:

[IO540]

Fantastic pics.

An engine failure over thick fog is no different to one on a dark overcast night in the middle of nowhere.

And nobody questions the latter one - in fact everyone is more than happy to take a grand off a PPL to teach them how to do it :O

[Gertrude the Wombat]

And nobody questions the latter one Oh Yes They Do - on recent threads on the night rating there is certainly a camp (myself included) who prefer not to do it (with one engine) precisely because of the "is that black underneath me fields or cloud" question.

[jayemm]

Slightly off-topic, but besides the legality, fog, unlike the dark (which tends to start and end at predictable times), can be full of false promise. I planned a trip to La Rochelle with a friend. Checked the Met including the TAFs, starting foggy clearing by 9am. It WAS a foggy morning but on the drive to my airfield I see patches of blue sky with the sun peeping through and think "yes, it'll burn off".

I get to the airfield and although it looks a little hazy, we think we are within IMC rules and take off. Within less than a minute I have climbed above the blanket of fog and cannot see the ground at all. Those holes I saw from the car on the way to the airport have all gone. I am flying to La Rochelle, so continue with the belief that "it'll burn off" ('by 9'). The blanket continues across the channel, across Cherbourg, across Mont-St-Michel, across Rennes.

My friend (ex-army chopper pilot) and I are now adjusting our route to avoid towns and wondering what to do if a) the engine fails and b) we get to La Rochelle and the blanket of fog is still around. We radio La Rochelle and to our relief they have glorious sunshine.

The blanket of fog cleared about 30 miles north of La Rochelle after almost 3 hours flying. The flight over fog was beautiful and nerve-racking, and was also a good lesson in the unpredictable nature of fog clearing!

The return trip was one of the clearest flights I've experienced.

[IO540]

GTW

I agree. That's why I choose to not do night flights, unless I have to. The 100nm FAA PPL night x/c requirement is one unavoidable example of a long night flight.

The privilege is handy to get back in the early evening.

jayemm

The problem you describe is much more of a problem (and probably much more common) the other way round: low cloud hangs near the western French coast, anywhere along that super coastline from La Rochelle to San Sebastian. When present, it tends to be OVC006-008 and it can hang in there for days. When arriving, you can do a DIY descent offshore (through a hole in the cloud, of course :O ) but they will never let you depart VFR and if that doesn't make you want an IR, nothing will.

[Snakecharmer]

Sorry to hear about the hour on the A34, but yesterday above patches of fog was glorious, much like DubTrub's pics... but we didn't get anything like as close to the pylons!

The joy of flying aerobatics in the smooth air over Berkshire (which was CAVOK), with a silky layer of fog beyond the Chilterns close by made yesterday one of the very best days of the year for me... seeing just the tip of Didcot power station poking up through the fog and spouting it's steam was quite surreal!

[Fuji Abound]

The purpose behind the UK “remaining in sight of the surface” requirements would seem to be quite clear. Firstly visual navigation is no longer possible - you might therefore get lost without training (or a GPS!). Secondly a descent on instruments will be required - the outcome of which is likely to be poor without training.

Unless I am missing the obvious both these problems remain for the non instrument rated pilot - whether it is above cloud or above fog. I don’t see in either situation how the flight would be legal without an IMC or IR.

Having been above fog more than a few times there remains four things in a SEP that makes me very uncomfortable - fog, night, hostile terrain, and very low cloud. Fog is beautiful BUT be in no doubt your chances following an engine failure will not be good. It is of course down to your own risk assessment and rightly so - there are those always happy to take the risk.

“One question, if there is fog and the conditions are below VMC minima can you fly with IMC rating or is it IFR and you have to file an IFR flight plan, then if conditions improve cancel the IFR plan and go to VFR? Also do you have to have a full IR rating to file and IFR Flight Plan?”

You can fly with an IMC, you don’t have to file an IFR flight plan but you can with an IMC. You can file an IFR flight plan without an IMC or IR - don’t confuse the met conditions with being IFR, you can perfectly well be IFR in perfect VMC on an IFR flight plan.

[Halfbaked_Boy]

Fuji - one reason cross-fixing with a couple of VORs is now included in the PPL syllabus is to ensure that a pilot has something else up his sleeve if visual separation from the ground ensues. Did make note of your use of the word 'might' though, merely opinionating. :ok:

Not making excuses because of course not everyone has the luxury of one - let alone two - radio navigation aids and it can be disorientating above banks and banks of cloud, but just suggesting that a well prepared pilot should never be in a position where they are adamantly unsure of their position... it's hard for London to confirm who they are looking at when you pass your mayday without at least an approximate position!

Either way, it's always worth recalling that handy reminder to us all that "Landings are compulsory, takeoffs are not," and I'm in full agreement with FujiFlyer that there are only so many ways 'in sight of the surface' can be interpreted. Low level fog? Apply the relevant IMC limitations that are going to affect you in the immediate, i.e. said fog.

Cheers, Jack.

[BEagle]

It's also why the practice diversion is included in the PPL Skill Test.....

I say to my lucky victims "Uh-oh - the Met Office lied to us. There's a sheet of fog covering everwhere beyond that town ahead. So, when you are ready to, please take me here" 'Here' being the diversion aerodrome whose information I then give him from Pooleys.

It's been freezing cold and foggy ALL DAY here in British West Oxfordshire - even the birds have been walking.

[Gertrude the Wombat]

It's also why the practice diversion is included in the PPL Skill Test..... Yes, very useful. I had to do a real one of those not long after passing my test for the second time round. Whether it was fog or low cloud I wasn't going down to check, but it was the sight of a mast sticking up through it that finally decided me to find another route to my destination.

[Aussie Andy]

I enjoyed my diversion from ~ overhead RAF Fairford @ 6,500' on Sunday when I learned Kemble was closed and diverted to Enstone when I learned they were clear. It was good because these days I typically cheat and just enter "Direct To" in the GPS, but Enstone isn't in our GPS database, so I had to do it the old fashioned way, with the map and my thumb! :ok: Was very pleased to find Enstone where I expceted it to be..! :O

Some pics if interested here: http://www.pprune.org/forums/showthread.php?s=&postid=2220285#post2220285 and here: http://www.flickr.com/photos/andyhardy/sets/1405427/

Andy :ok:

[IO540]

I wouldn't say that PPL training (not what I got 5 years ago, for sure) is adequate for navigation when surface features are not VERY clearly visible.

It's all very well to do a VOR/VOR (or VOR/DME but then DME is not covered in the PPL at all) fix but what if there isn't a VOR/DME in range?

Also, a lot of rental planes don't carry the equipment, or it doesn't work.

There are a lot of double standards in this business, but in this already massively over-regulated activity one must never argue for a reduction of privileges :O

[MayorQuimby]

You can file an IFR flight plan without an IMC or IR - don’t confuse the met conditions with being IFR...

Careful. In your jurisdiction maybe, but not in others.

[IO540]

Under simple CAA-only rules i.e. UK airspace, a G-reg plane and a UK issued PPL, the pilot can fly IFR (which includes filing a flight plan to that effect, either an airborne one or the full ICAO job) provided he remains within his VFR rules (3000m vis, clear of cloud, in sight of the surface etc) and remains in Class G (or, not exactly applicable to the UK, E or F).

What would be the point of a plain PPL flying under IFR?

IFR traffic gets a better service from ATC, and is much more likely to get a radar service, so that could be one reason. But this won't cut much ice if there is wall to wall sunshine everywhere; ATC do have windows too :O

I suppose that an experienced PPL flying in marginal VFR conditions would be better off calling himself "IFR".

As for putting "IFR" on an ICAO flight plan, that is something I don't see any point in. Especially if flying over 2000kg :O

[Fuji Abound]

MayorQuimby - correct, but of course Cadahar was talking about the IMC which is a unique UK rating and therefore I think his question was concerned with UK airspace. You can be on an IFR flight plan in the UK without any form of instrument rating so long as you remain outside of Class A and D airspace and meet the VFR visibility and cloud separation requirements. In the UK it is common for pilots to think that because they are IFR then they are also IMC - of course this is not so.

IO540 - I agree. That was of course the real basis behind my point, whilst being aware of the limited additional nav work now in the PPL syllabus.

As I commented earlier the problem with fog, just as with cloud, is that you are reliant on some other form of navigation than visual. Of course with a moving map it is easy and I guess most PPLs without an instrument rating would get on fine if they had taught themselves how to use a moving map GPS. How well they would get on with VORs and NDBs is more debatable - maybe OK straight after their training, maybe less well a year or so on if they had stopped practising these skills.

I have always thought it strange given this that in France and elsewhere VFR on top without instrument privileges is of course legal (on a French as opposed to UK license I might add). Is this because they do more instrument navigation training? It is also true of the States and you don’t seem to hear of all that many pilots getting themselves lost (do you??). Mind you I have always thought it a risky business without instrument training to get yourself above cloud relying on a forecast clearance in the cloud at your destination to get yourself down. Moreover in the event of an engine failure whilst over cloud you will still need some instrument skills to get yourself visual and that certainly is not the time you want to be under pressure when you have enough to cope with anyway!

I read a fascinating account of a fellow in the States in a Money who suffered a total engine failure at FL140 whilst clear on top, and did a dead stick landing into an airport near the edge of his glide range descending through 4,000 feet of undercast. I might add he was instrument rated, but it would be possible in the States and France for a non instrument rated pilot to find themselves in the same situation.



PS just seen I0540s post sorry for the duplication. I would just add there is at least one occasion I can think where a non-IRed pilot might declare himself IFR that is very appropriate at this time of year - flying into the dreaded sum! Often rear viz is excellent but it can be a real struggle to pick up aircraft ahead. I see no reason not to tell ATC you are IFR and why - as I0540 says you will get a better service even if they are busy if you explain why and it also does no harm adopting IFR separation.

[Mike Cross]

I was flying in company with Mono on the trip in question.

We flew Popham to Kemble via South Marston and Blakehill Farm. Fairford is NOTAMmed active so we spoke to Brize en-route.

All clear of fog to South Marston, which was clearly visible. Blakehill Farm was under fog but Kemble was visible, as was Aston Down. The odd patch of ground was also visible in between and we were at 2500 ft. Effectively there was a ribbon of fog with totally clear vis on either side of it.

That's the background. From a pure survivability point of view an engine failure would have entailed heading for the nearest reachable bit of visible ground and I don't think we were at any time out of reach of visible surface.

Fog is less than a couple of wingspans deep and goes down to the ground. The outcome of an enforced descent through it is likely to be the same whether you have an IMC, IR or vanilla PPL.

So to me flying over a band of fog where you can see both sides is a bit like flying over a stretch of hostile terrain where your choices are limited if the whirly thing at the front stops going round. All aircraft engines recognise these situations and give you subtle aural stimuli just to keep you on your toes.

[S-Works]

We did the Kemble diversion thing on Sunday as well. The fog was great to fly over and I got some great pics as well as meeting the unsuspecting Aussie Andy flying the over engined warrior! Was that a former man in the pink jeans?

First time in about 1500hrs I had to get the map out and do a bit of old fashioned navigation, pleased to say my thumb is still the same size and Enstone appeared where expected!!!

[cblinton@blueyonder.]

I was stuck under a layer at Glos while you were all finding holes from above.

No other meaning intended:)

[Aussie Andy]

bose-x,Was that a former man in the pink jeans?My brother and I reckoned the same thing!!

Good to meet you; did you end up at Turweston eventually, or head straight home?

Andy ;)

[S-Works]

We went on to Turweston, it would have been rude not to after I ran up your phone bill!! We had a coffee and fuel and then onwards. Apart from the aborted Kemble visit it turned out to be a great days flying.

I am glad the consenus on "miss" pink jeans was the same! :D

steve
:D

[Mike Cross]

Here's Mono on Sunday and that looks like Greenham Common behind him. Note the lack of fog!
http://mrc0001.users.btopenworld.com/webimages/IMG_3287.jpg

Over Highclere Castle, now you can see the fog to the north.
http://mrc0001.users.btopenworld.com/webimages/IMG_3284.jpg

[Irv]

But it might not stay as fog... Just a little increase in wind speed, and the fog lifts into stratus.... "I learned about flying from that", Pilot Magzine Dec 1997 for those of you with long shelves.

[Deano777]

Indeed Irv, as happened here in the SW yesterday around Filton, I have just completed Mod1 ATPLs and the wife was asking about the fog & how it forms (bless her, she is interested really) , I told her the conditions for it forming and what happens if the wind speed increases, we did a lil Christmas shopping and when we came out we had the low stratus due to an increase in wind, result was as expected, the sun had totally disappeared and the visability would have been even worse had we been in the air.

[Irv]

Deano777 - if it's a surprise when you come out of the shop, imagine what it's like when you're happily crossing over it at the level it decides to 'stratrate' at. (made that word up, don't use it in your ATPL classroom discussions :) )

[old_fog_bound]

Ooh, sorry to annoy so many of you this weekend, I can't control the winds so I am afraid I was stuck over most of the uk last weekend.

I do apologies for this of course but never mind, keeps you lot on your toes eh!

Nice pictures by the way. It is not that often I get to see myself. Do you have anymore?

This week, I will be covering almost everywhere, tending to settle overnight and clearing away in the mornings, don't like the sun too much don't you know, makes the place warm, can't handle warm me, just nice cold ground for me to hug and a slight wind.

Safe flying guys. :)

[Aussie Andy]

But it might not stay as fog... Just a little increase in wind speed, and the fog lifts into stratus.... "I learned about flying from that", Pilot Magzine Dec 1997 for those of you with long shelves. Good point Irv - hence importance of having known clear alternates &/or an IMC or IR rating!!

Now I just need a way to keep my IMC current and up-to-speed - how about an IMC Master-Class!?!

Nice pictures by the way. It is not that often I get to see myself. Do you have anymore? See http://forums.flyer.co.uk/viewtopic.php?t=17843&postdays=0&postorder=asc&start=90 and http://www.flickr.com/photos/andyhardy/sets/1405427/

Andy :ok:

[S-Works]

You dont need an IMC Andy, the howling noise that the Warriokee that you were flying scares the weather away!

[Aussie Andy]

"Warriokee" - nice one! :p It's a PA28-236 Dakota, don't you know!!

I guess I should've done the engine run-up a bit further away from the Enstone shack!?

Andy :O

[S-Works]

Still no match for my cessna..... :D

[Aussie Andy]

When you landed my brother said "wow, why can't you land like that!"

I think his drugs are beginning to wear off..!

Andy :ok:

[cubflyer]

Missed flying over all the fog this weekend, but it looks like I'll have the chance in the next few days still!
Great fun, but as others have said you need to be careful to make sure you know where you are and have an escape plan.
As for "clear of cloud and in sight of the surface" surely that means exactly as it says. As long as you can see some of the surface, whether a hill in the distance, or down through some holes thats good enough, legally.
Yes, if your engine stops, you have a problem, but you also do flying in the mountains or over the water or even over a large forest.
Those that think they are better off flying with an IMC rating or IR over the fog I think are mistaken. Thats not going to make much difference if your engine fails and anyway, the fog is probably below the minimums for your rating anyway. The only advantage you would have with such a rating is if your plan wasnt so good and the fog moved leaving you with nowhere to land VFR. Of course again assuming that somewhere with an approach procedure was above your minima!

[Aussie Andy]

Yes, if your engine stops, you have a problem, but you also do flying in the mountains or over the water or even over a large forest Yes, I very much agree and would add to the list in places like the LA Basin, San Francisco, Sydney etc. where the "land clear" rules seem to be different, GA routinely fly over very built up areas for extended periods with the best option being to find a golf course or a motorway..!

Of course I don't mean to be flippant regarding the need to have a way out should the fan-stop, all I'm saying is that we are typically very lucky here with our mixed rural-urban envirnments outside of the metropolis(es) in that mostly we have landable fields nearby except for over the hills (Wales, Pennines, Scotland etc) and the Channel / Irish Sea / North Sea etc..

Andy :ok:

[Barnaby the Bear]

It may have already been said before, but although you maybe required, by law to remain 'clear of cloud' and in sight of the surface. You have to way up the pro's and cons. Do you descend into the fog to try and find, the surface? Hit the surface or obstacle? Or remain VMC, assess whether the fog is due to local topography (valleys etc) and continue on same track. Or Turn back to where there was no fog, and land safely.

I would rather survive and be bollocked for bending the rules, than be injured or killed for trying to apply the rules.

I have only a little flying experience, so that is only my opinion, and the opinion of some others spoken to on the topic.

But with all that in mind, son't forget to ask your friendly local ATC unit, or even D&D (in UK) for help, if you ever get into difficulty.

Safe flying!!!!!!! :cool:

[Halfbaked_Boy]

Barnaby, as far as I understand it, you can bend ANY rule the ICAO/CAA/JAA or otherwise has conjured up for the purposes of saving life or the prevention of serious injury.

Cheers, Jack.

[S-Works]

Of course Jack but undertaking a flight with the view that if it goes wrong you can bend the rules is questionable.......

[Halfbaked_Boy]

I'm trying to distinguish between things going 'wrong' and things turning 'lethal' here - the latter of which should only happen if something is wrong with the machine or the passengers, just to touch the tip of the iceberg. Human error leading to such a situation is so easily avoided with a good plan of action on terra firma before taking an aircraft away from the ground.

And yes, the idea you quoted me on is questionable, I agree.

Cheers and thanks for the input, Jack.

[S-Works]

wrong and lethal are only differentiated by the numbers dead. But a nonetheless a mature answer for one so young.

:D