Flying into Cloud

[Stratus Fractus]

OK please go easy..Yes, I have tried a search, instructors and the books. This has always been a grey area for me and a few others I have spoken to.

2 similar situations:

1) I am flying VFR above 3000ft in the UK, Class G, with an IMC rating. I want to fly through a couple of small clouds to experience real IMC in case I ever have to do it for real.

2) I want to climb through a thin layer of stratus to get in the clearer air up top.

As I fly toward the cloud I will no longer be flying in VMC because I have less than 1500m lateral seperation from cloud. If I am not in VMC I can no longer be flying VFR, so I must be IFR. But I haven't filed a flight plan for this local bimble, and I am not at the correct flight level because I am just meandering around enjoying myself, so I am not IFR either.

I am probably already receiving a FIS, or a RIS.

I have already done a risk assessment re: ice, turbulence, gliders, terrain clearance. This hypothetical situation is considered safe.

How can I do this legally? What calls are necassary? Does anybody else feel strong urges to fly around, through and over the whitestuff without telling anyone? Slipping the surely bonds etc...

Many thanks in advance.

[mm_flynn]

Because you are over 3000 ft (assuming that is the TA where you are), you must be flying the appropriate quadrantal Flight Level once you go IFR (you can do this VFR as well of course). As you point out, you are either IFR or illegal the moment you are not in VMC (i.e. less than 1500 m (edit to fix - not feet) from cloud.


As a note - you can get close to the cloud as a plain PPL because you will still have your minimum forward visibility (which , along with being in sight of ground, defines if you can legally fly in the met conditions).

There is no 'appropriate quadrantal' when climbing/descending or manoeuvring so this is not an issue in scenario 2.

You then flip the big VFR/IFR switch in your head and realise the new rules you have to follow are fly at quadrantal flight level and be 1000 feet above the highest obstacle within 5 miles (which is pretty likely to be true at 3000 ft) and presto chango you are legally ready to dip into the cloud. This process is equally valid if you are below 3000, except you only have the minimum height rule when you are in the clag.

If you are receiving a RIS and have explicitly told the controller you were VFR, it is probably good form to tell him you are now in IMC.

With regard to flight plans. You don't need to be on a flight plan or a clearance in Class G for either IFR or VFR flight. If you are in controlled airspace, you will already be on a flight plan (or infringing :eek: ) and if it was a VFR clearance then you have to remain in VMC or ask for it to be changed.

[Rod1]

We are also assuming that your aircraft is appropriately equipped and cleared for flight in IMC conditions. You could be fully licensed and flying a fully equipped aircraft on a CAA permit, which would make such a flight illegal.

Rod1

[Stratus Fractus]

mm flynn

Many Thanks for your prompt reply. So basically with an IMC rating PPL:

Above 3000ft
In order to get into the cloud legally I need to be straight and level at the appropriate quadrantal flight level. OR, I need to be climbing /descending / manoeuvering (which is easily arranged...:E)

Below 3000ft
I just need to remain 1000ft above the highest obstacle within 5nm.

And to inform the approriate ATSU that I am now IMC.

[Stratus Fractus]

Yes, and assuming the aircraft is appropriately equipped / licensed..

[waldopepper42]

Whether at 1,000, 3,000, or 30,000 feet - you still need to be 1000ft above the highest obstacle within 5nm.

'Cos it hurts when you make a "CFIT" :) :)

[mm_flynn]

Whether at 1,000, 3,000, or 30,000 feet - you still need to be 1000ft above the highest obstacle within 5nm.

'Cos it hurts when you make a "CFIT"

Technically the "1000 feet above the highest obstacle within 5nm" doesn't apply if you are below 3000 feet and visual with the ground - though hacking along 500 feet above the trees at 245 knots in 300m vis fog defo is in the legal but dumb category!

[englishal]

3000 AGL or 3000 MSL ?

I believe (I have forgotten :O ) that the quadrantal level is only applicable > 3000 AGL (bearing in mind that in Scotland you could be at FL60 and below 3000 AGL so quadrantal's do not apply).

[FlyingForFun]

I believe (I have forgotten ) that the quadrantal level is only applicable > 3000 AGL (bearing in mind that in Scotland you could be at FL60 and below 3000 AGL so quadrantal's do not apply).
Sorry englishal, but that's not correct. (Or, to put it another way, you are correct in thinking you may have forgotten! ;))

The relevant rule is Rule 30. Load CAP393 (http://www.caa.co.uk/docs/33/CAP393.PDF) and scroll to page 293 in the .PDF file (Section 2, Page 19):

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

[adverse-bump]

If you are flying S+L and want to climb above a layer of cloud ( through it ) try filling an airbourne flight plan. As in " G-CLUD request tempory change IFR climbing FL50 once estabilshed request change VFR on top" or something like tht, it has always worked for me...

[gcolyer]

Quadrangle rule is valid when above the transition level, which kind of depends on what FL you plan to fly and the QNH. In some scenarios if the QNH is right or wrong whichever way you look at it the transition altitude or the quadrant level you need to fly is not available for your heading and the FL that you plan to fly, in which case you need to pick the next FL avaible for that heading, which in turn gives you the Transition altitude.

[IRRenewal]

VFR on topSince 'VFR' requires one to be 'in sight of the surface', how can one ever be 'VFR on top'? (Talking UK here, don't care what they do in other countries.)

[Islander2]

Since 'VFR' requires one to be 'in sight of the surface', how can one ever be 'VFR on top'? (Talking UK here, don't care what they do in other countries.)There's no such VFR rule in the UK. Maybe you are referring to the plain vanilla PPL licence restriction? An IMCR or IR holder is legally entitled to fly 'VFR on top'.

[Awyrennwr]

VFR Does not require that you be in sight of the surface, that is just a restriction on the UK issued PPL. With the IMC rating or IR, this restriction is removed and you can fly VFR on top.
When you enter cloud in class G just inform ATC you are IMC (and IFR) and comply with IFR. Cruise at quadrantals, climb and descend as required, there is no requirement to be straight and level before becoming IMC.

[Dysonsphere]

Er if you can see the ground thru a gap how big does that gap have to be (judt wondered as turned dack the other day due to lack of gap)

[mm_flynn]

Awyrennwr, adverse-bump

There is no need to talk with ATC in Class G when changing between IFR and VFR, nor is there a need to receive any service at all. While you may find that ATC offer to upgrade your service from FIS to RIS, or offer RAS if you say you are IFR - there is no requirement to avail oneself of their services.


The phrase VFR on Top should be used with care because it means different things to different people. It could be flying VFR above a cloud layer or in the US it could also be flying a specific type of IFR clearance above a cloud layer remaining VMC and complying with the VFR semicircular altitudes (with the altitude selected at pilot discretion)

[englishal]

Thanks FFF.....

If you are flying S+L and want to climb above a layer of cloud ( through it ) try filling an airbourne flight plan. As in " G-CLUD request tempory change IFR climbing FL50 once estabilshed request change VFR on top" or something like tht, it has always worked for me...

I wouldn't bother with any of that outside CAS. I would just tell them "G-CLUD climbing FL050 IFR IMC" (if in IMC). If in CAS I'd request "G-CLUD request climb FL050 IFR IMC".

"VFR On top" is not really applicable in the UK. As mentioned, in the USA you can be issed a "IFR to VFR on top" clearance which is an IFR clearance until you cancel IFR when you are VFR "on top" again. Very useful it is too, but once ontop you are VFR again and VFR rules apply.

In controlled airspace it is a different matter of course (class Delta for IMCr holder). Here you need a clearance but they will only clear you to some point on the edge of their CAS, once you leave CAS it is up to you what you do. Inside their CAS you will be under a "Radar Control" service. ATC units outside CAS cannot issue a clearance to someone departing IFR with an IMCr (i.e. not entering the airways).

[IO540]

Er if you can see the ground thru a gap how big does that gap have to be (judt wondered as turned dack the other day due to lack of gap)

I've never come across any reference, or details of any enforcement, on this.

I guess the reason why the UK CAA imposes this additional requirement (additional to an ICAO PPL) is that UK pilots are not taught to navigate using methods other than dead reckoning.

It's all a bit silly since you can be in clear conditions but in poor vis e.g. 3000m which is still UK PPL legal but you can't do DR in 3k vis. Well, instructors can but that's because they know the area ;)

[Rod1]

“I guess the reason why the UK CAA imposes this additional requirement (additional to an ICAO PPL) is that UK pilots are not taught to navigate using methods other than dead reckoning.”

Radio nav is now a standard part of PPL training. The new R/E PPL will probably follow ICAO rules so we may get VFR on top back.

Rod1

[Stratus Fractus]

Thankyou all for your input, I have found this discussion very usefull.

As for navigating without sight of the surface, I was taught VOR use (tracking and triangulation) during my PPL.

I think the real use of the "within sight of surface" rule is that as a "plain" PPL you need to be able to see the ground to get back to it. You haven't learn't instrument approach procedures yet. If you fly off across scattered cloud which becomes broken and then over(under)cast; how do you get back down below when you want to? Maybe the weatherman is wrong and its not "scattered" at the destination aerodrome, or anywhere else within range...

[mm_flynn]

SF,

The issue of getting back down is equally true in all of the countries that do allow VFR flight above a cloud deck by plain PPLs. They admonish pilots to use good judgement and planning so you are sure it is a localised cloud deck an can get back down. This difference in rules doesn't seem to show up in a higher level of safety in the UK. I suspect the logic of SF and IO540 was used by the CAA drafters who came up with the rules.

[Tall_guy_in_a_152]

Can I extend this discussion with a related question based on circumstances I have found myself in a couple of times but IMC training did not prepare me for.

Say I am flying in VMC between two solid cloud layers (or cloud and CAS), but the vertical separation is only 1000ft. There is not a legal FL available within the 1000ft. This is all happening above the transition level.

My options appear to be:
1) Fly IFR in cloud above or below the VMC layer
2) VFR below cloud
3) VFR in the VMC layer, legally at any altitude I choose (subject to usual VFR rules).
4) stay at home

(3) appeals far more than (1),(2) or (4), but what altitude to pick? What I have done is pick a quadrantual level + or - 250ft and ideally putting me furthest from head-on traffic as possible. If VFR then I should be at an altitude rather than FL, but surely in this environment setting 1013 would be more sensible?

Supplementary question, if there are a few fluffy clouds in my (mostly) VMC layer, would it be best to just abandon any pretence of VMC and go IFR in IMC or would you "ride out" a few seconds in the clouds?

I appreciate that there probably are not right or wrong answers to the above, but opinions are welcome.

[dublinpilot]

Tall guy.....you've confused me with a couple of things you said....


If the vertical serperation between the cloud layers is only 1000ft, and you are above the transition level, then you are not meeting the requirement of VFR. You need to be seperated from cloud 1000ft vertically under VFR above 3000ft. To meet his you'd need a 2000ft gap between the cloud layers. So your option 3 doesn't seem to be legal. It may very well be the most sensible though ;)

You also say
If VFR then I should be at an altitude rather than FL, but surely in this environment setting 1013 would be more sensible?


Why? There is no prohibition on using FL's instead of altitudes when under VFR, in fact it makes sense to use FL's as that's what everyone else will be using. Or did you mean something else?

dp

[bookworm]

If the vertical serperation between the cloud layers is only 1000ft, and you are above the transition level, then you are not meeting the requirement of VFR. You need to be seperated from cloud 1000ft vertically under VFR above 3000ft. To meet his you'd need a 2000ft gap between the cloud layers. So your option 3 doesn't seem to be legal. It may very well be the most sensible though

Indeed. Option 3 may not be technicaly legal, but the regulation is likely to be almost unenforcable (ever heard of a prosecution for breach of the quadrantal rule?) and it would seem to be the best option from the point of view of safety management. On most days, it's likely to put you at less risk of collision than VMC below cloud, and probably less than IFR in the cloud.

[Tall_guy_in_a_152]

Good points, DP. I had not considered 1000ft from cloud up and down.

I am under the impression (probably wrongly) that when VFR one flies quadrantal on QNH and IFR on 1013. I agree that for the purposes of collision avoidance that is a bit daft!

Thanks Bookworm, for the purpose of this discussion I am more interested in "sensible" rather than legal! Not that I would ever do anything illegal, of course.

[smith]

If flying VFR above the transition altitude I was under the impression it was advisable, but not mandatory to fly the quadrantial rule. ALso at low altitude eg 4,000ft, if you set 1013 and the QNH is vastly different you could be hundreds of feet out.

[IO540]

However, in Class G, few people bother about any of this.

There is a statistical argument for flying the quad or semi levels/altitudes but as far as I can tell it's rather tenuous.

Cloud spacing is unenforceable - even if you could actually estimate the distance with any accuracy.