Maintaining VMC - Aussie Airspace

[flyingpom]

All, so I have a quick question regarding maintaining VMC as I have my PPL test coming up ( with Ken Andrews ).

Lets say I provisionally look to fly at my planned altitude e.g 5500 feet but have some cloud in front of me that looks like it's pretty much on my level. I'm interested in your thoughts regarding either:

- Descending below to maintain 1000ft vertical separation
Vs
- Performing small doglegs ( 30 / 45 / 60 degrees etc )

Also, any tips on ways of establishing how close cloud actuallly gets ( i.e whether it's within 1500m horizontally or 1000ft vertically )

[Captain Smithy]

Don't know the particulars of Oz flying but if you can't reach your planned altitude to maintain VMC go lower. Or of you're already in the cruise you can try to go around it. If things get really bad you turn back.

Is VFR on top allowed Dunnunda?

Smithy

[PPRuNeUser0163]

Flyingpom,

you will be fine Ken is an awesome guy..

If you see cloud at planned level enroute (such as i did in my PPL) descend below (as long as you CAN maintain 1000ft clearance above builtup areas, 500ft above non builtup per AIPs- that is massively important).

If its over mountainous terrain and you can't consider a diversion- dont just do random 'doglegs as you say' but rather plan via a medium sized township ideally if possible.

On judging cloud distance etc how long is a piece of string? It's a process which is just helped by experience but you will well notice if you are getting anywhere near cloud- if its few then you will have no issues.

DO not go vfr on top under any circumstances in a test. May be good for overseas tests but I think its downright dangerous on a VFR PPL, CPL test in Australia. What if you cant find a gap ?

Good luck and remember the ato wants to pass you

[Capt Claret]

Also, any tips on ways of establishing how close cloud actuallly gets ( i.e whether it's within 1500m horizontally or 1000ft vertically )

It often seems to me that I'm no better at determining the distance from cloud now, than I was 27 years ago when I started out.

[AerocatS2A]

- Descending below to maintain 1000ft vertical separation
Vs
- Performing small doglegs ( 30 / 45 / 60 degrees etc )

I'd go for vertical separation if possible (i.e., legal and safe). Dodging clouds laterally, although fun on the right day, just increases both your workload and the chances you'll inadvertently go IMC.

Also, any tips on ways of establishing how close cloud actuallly gets ( i.e whether it's within 1500m horizontally or 1000ft vertically )

There's no real accurate way of working out horizontal distance. The problem is that you can guestimate all you like but you never receive any feedback as to whether your guess is correct or not, with no feedback there is no way of knowing whether you should be changing your estimates. In the end you just fly far enough away from the clouds so that you feel comfortable. All I can suggest is to try and imagine an IFR aircraft suddenly appearing out of those clouds and figure whether you'd have time to take avoiding action or not.

To work out vertical distance you just need to spend time 1000' below a known cloud level and get used to what it looks like.

[UnderneathTheRadar]

just increases both your workload and the chances you'll inadvertently go IMC.

and the chance you'll get lost.....

Best not to go over unless you're sure you can see the other side - you're visual nav only and flying over a waypoint whilst on top would not be a good move.

If you're really not sure, just get down below 3000' or 1000' AGL and make sure your wingtip misses.....

UTR

[Ex FSO GRIFFO]

In the situation you describe, I found when I was doing my navs (in another era), that if I drew the ATO's attention to my 'problem' and 'discussed' it at the time, then that helped.
And when I was instructing, I did appreciate the student letting me know what he was thinking, so at least I knew he was considering something...

He may give you the advice you need, even in the form of a question - as long as you make it clear that you are considering this, or that, to avoid 'breaking' the VMC rules, and you are prepared to make the decisions.

It is a PPL test, and although you do have to display your skills and make your decisions, it ain't a CPL or higher test, and your experience level is not supposed / expected to be all-encompassing at this stage....

The rest is how 'comfortable' you feel - as 'Aerocat' so aptly says, fly horizontally far enough that you feel comfortable, and make some remark if necessary to that effect, and during any training you have prior to the test, see if you can keep the cloud base 'well above' the horizon.

That is a guide to your vert. separation- if your 'circle of vision' to the far horizon is getting smaller due cloud above, then you are far too close and need to descend accordingly.

I guess you could always try to fly at least 1,000ft below the forecast cloud base, and see how that turns out.
In any case, try to enjoy as much as you can, talk to the guy if that is 'within the current rules'....

Good Luck

[cficare]

When your flying below the cloud and the ATO asks how far (vertically) you are from the cloud.....DONT say something like ...'maybe 600/700'..??'

Say ..'.I reckon about 1000' !!...he can't prove you wrong without breaking the rules!!

[fanning]

My testing officer told me he "forgot to bring his ruler with him"

I knew I was fine after that

Good luck

[capt787]

in a test perspective, i will go with the descent option because it is easier to navigate visually when you are flying a straight line then when you are doing zig-zag. once you turned away from your original heading sometimes it can be hard to judge your track made good without using the gps, especially if you have to zig-zag for long period of time (> 5 mins).

the bottom line is if you are taking an exam, always choose the safest option (i.e. descent and maintain 1000ft vertical seperation below the cloud if you are above 3000ft AMSL or 1000ft AGL).

Good luck with your test!

[BrazDriver]

This should be taught as part of your training, not a last minute prior to test day. That is what navex's are for. You will find this conundrum is not just isolated to you. Its great you wish to find out, its also what you pay your instructor for!

There have been some great answers posted though. Best of luck for the test.

[flyingpom]

This was discussed with my instructor. I just wanted to gauge some other opinions. Thanks for the great responses. Here's hoping Ken falls asleep and doesn't notice the cloud

[Feather #3]

Finally, don't forget that turning back is always an option!!

G'day

[Pilot DAR]

Best not to go over unless you're sure you can see the other side

Ahhh, another good reason not to go over is that "VFR" flight is flight conducted with visual reference to the ground. If you're on top of cloud, you have probably reduced or eliminated your practical reference to the ground. That's very bad for safety, and regulatory compliance.

If in doubt, turn away, while considering a descent. Do not commit yourself to flying under until you believe that is safe - meaning don't allow turning away to stop being an option. If you have approached a cloud to a point where a rapid descent, or circling or "S" turns are required to prevent entering it, you were not paying attention far enough ahead. Failing to think far enough ahead is a cause of unsafe situations in aviation.

Good luck on your test..

[blacknight]

If you're really not sure, just get down below 3000' or 1000' AGL and make sure your wingtip misses.....

Probably not a good idea in a test. Too hard to navigate and too dangerous. Lots of well qualified pilots use and abuse this rule far too often. This rule is only intended for a short hop or to get out of trouble.

You will do well in your test because you are already planning for the possibilities. The golden rule is don't take the plane anywhere you haven't been in your mind at least 10 minutes ago and always have a reason for going there!!

Good luck.

[Seagull V]

Some tips.

Cloud Base - If you can see the horizon clearly, the base is above your altitude. If the cloud base is just touching the horizon, the base is at your altitude. If the cloud base obscures the horizon then the cloud is below your altitude.

So if you really must measure the cloud base then climb until the base is just touching the horizon. Then descend. Since cloud base is often not uniform pay attention ahead and always maintain a clear horizon.

Can't see an horizon due rain or other poor vis? What are you doing there?

If you choose to Scud Run then remember that you are better of to have your "wheels in the trees" than to have your fin in the cloud. That way you can see what lies ahead.

Horizontal distance - Very arbitary - The "what feels good" comment made by other posters is correct.

Consider your options - Dont wait for bad weather to come along - When flying VFR you should continously consider your options.

The proper order of consideration is

• Continue - As planned to destination
• Detour - Track to destination via another route
• Hold - Wait for the wx to improve- Have you fuel/Daylight for this?
• Return to starting point or Divert to a prepared landing ground
• Land off airport - A good landing on a bad surface is more survivable than a bad landingon the best surface.

[Kelly Slater]

If you put your bottle of water on the glare shield, you can use it as a spirit level and sight along it to see whether or not you are above the level of the cloud. Works best with a clear bottle, ha. You can get the same outcome by getting low with your eye on the glare shield but it doesn't look as impressive.

[UnderneathTheRadar]

Sorry - an oldie but a goody:

A student became lost during a solo cross-country flight. While attempting to locate the aircraft on radar, ATC asked, 'What was your last known position?' Student: 'When I was number one for takeoff.'

UTR

[Tmbstory]

Clouds

When looking at a cloud, if you can see an object ( another cloud, horizon terrain etc.) beyond the cloud you are looking at , then you are higher.

Enjoy the flying.

Tmb

[Ixixly]

Hasn't been said yet but use all available resources as well. Generally you'll be going to an airfield that is a CTAF, generally on 126.7, there are a lot of aerodromes that operate on it and some will be close to where you are going. If you hear
"ABC departs 'The airfield you want to go to' at time...blah blah blah" Check their rego and give them a call and ask them what the cloud is like there!

Has gotten me out of trouble before, heading towards an aerodrome with no AWIS and your a bit unsure listen to the other traffic in the area and ask for some help if you need it "ABC, DEF, enroute to "the airfield" can you tell me what the cloud base is there?"

Sometimes you'll find out its a lot lower than you expect or a lot higher, sometimes you'll get a real friendly response "Yeah, just came from your direction, gets a little low over the ranges but clears up nicely on the otherside" or "Just came from there, IFR...your IFR right? Your gonna need to be..."

Good luck with your test, remember good command decisions, use all the resources available to you appropriately, don't go over the top though!!