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TO in VFR , not for long, interpretation question


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At Canberra in winter, it tends to be nice and fine at sunrise,  not a cloud anywhere, subzero....

...and 15 minutes later , out of no where, over about 5 minutes, a fog appears and descends for several hours. it rises to about 700' AGL and can sit there until noon.....

Now, according to the VFRG , the aerodrome you begin a journey from , the WX needs to be good for 1 hour after departure (for a possible return), in order to satisfy the VFR.

This would mean that in the the above  fog appearance case in Canberra,  a takeoff at sunrise  with no cloud and blue skies as far as the eye can see, would NOT satisfy the VFR because the fog rolls in soon after .

And,  if this was a home airport, you'd be hard pressed to make an argument that you were not familiar with this common condition.

 

A strict interpretation would make this airport a fairly useless airport in winter for a VFR pilot.

The fog 99% of the time confined to the Canberra basin. Fly about 5 nm in any direction and it wont be foggy , but it will still be foggy at the aerodrome you took off from (which was not foggy , but was 'magnificent' at TO) .

 

comments please?

 

glen

 

Edited by RFguy
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I've either misinterpreted that bit, or completely forgotten it. The only 60 minute "requirement" for departure I can recall is if you do not hold a current forecast for your destination and you intend to obtain that in flight, which you can do for upto 30 minutes after departure. So takeoff, fly 30 min out, get forecast - it's crap - return to origin = need 60 mins good weather. 

 

But if you have a known-good forecast for your destination, you can depart if you can maintain VMC and your departure point can immediately go IMC, with not a care in the world.

 

What's the reference in the VFRG? I might need to hit the books again!

Edited by KRviator
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OK, I did not read it properly. I think that's because I read that in some training book, and I might have not got the full text.

You are correct!

"Section 2, pre flight planning, preparation, pre-flight information"

Thanks !

 

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Edited by RFguy
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as strictly, not everywhere I might go as a destination -might not have a forecast....

..on 500nm XC to  non registered airstrip.

However, en-route, there would be plenty of options for aerodromes with forecasts.

 

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There's actually a really interesting discussion going on over at PPRune at the moment regarding alternates and the question "Do you need an alternate if your destination does not have a TAF?"

 

My reading of the AIP is "yes, you do", but it's a ridiculous proposition - how many of us fly to airfields that no longer - or have never had - a TAF service? CAVU weather and you need an alternate - and that alternate cannot be an airport that itself requires an alternate, so you need to plan to somewhere that does have a TAF. WTF?!?

 

Quote

11.7.1 General

11.7.1.1 A pilot in command must make provision for flight to an alternate aerodrome, when required, in accordance with the following paragraphs.

11.7.1.2 When a flight is required to provide for an alternate aerodrome, any aerodrome may be so nominated for that flight provided:

a. it is suitable as a destination for that flight and

b. it is not an aerodrome for which that flight would require to provide for an alternate aerodrome.

11.7.1.3 When an aerodrome forecast is not available or is "provisional", the pilot in command must make provision for a suitable alternate that has a firm forecast.

 

The kicker is the word "aerodrome" forecast. A GAF is not an aerodrome forecast, so we would, appear, to not be able to rely on the visibility or weather in the GAF when it comes to considering whether or not our destination is above the VFR Alternate Minima.

Edited by KRviator
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8 minutes ago, KRviator said:

There's actually a really interesting discussion going on over at PPRune at the moment regarding alternates and the question "Do you need an alternate if your destination does not have a TAF?"

 

My reading of the AIP is "yes, you do", but it's a ridiculous proposition - how many of us fly to airfields that no longer - or have never had - a TAF service? CAVU weather and you need an alternate - and that alternate cannot be an airport that itself requires an alternate, so you need to plan to somewhere that does have a TAF. WTF?!?

 

 

The kicker is the word "aerodrome" forecast. A GAF is not an aerodrome forecast, so we would, appear, to not be able to rely on the visibility or weather in the GAF when it comes to considering whether or not our destination is above the VFR Alternate Minima.

Which further complicates it if the only aerodrome with a TAF near you has active class C and you don’t meet the equipment / qualifications to fly in class c....

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Can't say I am up with the Rule Book but I always plan with alternate & en-rout airdrome in mind - its not just weather that can put a spanner in the destination airport closing unexpectedly. I carry 60 minute emergency/holding fuel, have sussed out alternate strip radio frequencies, special instructions and AGL - may sound a tad anal but then that just me and it makes me feel I have acted professionally.

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You can't FLY in non VFR conditions either so if the area forecast is OK any landing field within it should be covered or you could get information from a local by arrangement. You are supposed to make your best effort to get related info  Suitably Met. qualified pilots can make their own weather observations. Fog is related to local high relative humidity (wet and dry bulb temps close together) likely in the evening as well as early morning or sea fog (mixing) can drift over the area.. By the way if you fly in sub zero temps you can easily get airframe icing as it may cause condensation on your cool airframe from a warmer  airmass if it's got enough moisture in it. Often occurs on a descent. Nev

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Hi everybody. Interesting discussion has ensued

 

KRaviator - that is as I read it also, you need a alternate for an alternate and it must have a TAF.

 

But, the way Nev  suggests- you are required to make your best effort to get the met info you need. - that makes the most COMMON SENSE interpretation.

 

-yeah the fog appears here  at 15 min past sunrise , and can hang around till lunch. So once you have decided to leave YSCB, a VFR pilot isn't getting back in. And it must be remembered - around Canberra , there are rocks in the clouds....all over the place.

 

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Yes .It's not easy terrain in most directions out of Canberra. Having an extensive knowledge of weather is very necessary for U/L pilots on cross countries. A low cloud base means high local relative humidity and it only has to cool slightly and the base drops further. A coastal sea breeze will bring moisture with it and form clouds inland. Nev

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@facthunter I don't think anyone's suggesting flying VFR into IMC, rather, your departure point can go IMC immediately after you've left and, so long as you won't need to return (because you've got a known-good forecast) that's fine.

 

I can't recall specifically planning a destination alternate in any of my XC flights since training, but have always thought about "where can I go if...." when airborne. Though in re-reading the AIP it looks like I've been a naughty boy, as I've relied on the GAF for assessing whether the destination is above the VFR alternate minima, simply due to the fact most of my flying is to airports that don't have a TAF service. 

 

I'm just thinking from the point of flying around the Newcastle area, if you are planned to arrive at Cessnock, there's no TAF, so you have to hold Maitland as your alternate. But hang on, Maitland is below the VFR Alternate Minima right now, so you can't hold Maitland. Williamtown is out lest an F18 rise and smite thee, so that leaves Bankstown or Taree as the only two options! I'm sure there would be dozens more examples like that Australia wide which makes me wonder if I am actually wrong with that AIP reference and there's another reference tucked away somewhere, but if there is, I haven't found it yet!!

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in my local area the fog is there at dawn and then lifts completely.

A local CFI decided to take off with a student for a trip to Bundaberg as soon as it stared clearing.

Away he goes, but it doesn't clear, his point of departure is covered in fog again as soon as he took off. No worries, carry on to Bundy, but it doesn't clear and he is flying over a fog bank, with a low cloud layer above.

Luckily he hears radio chatter from the coast near Bundy and they tell him it is clear there, so no problems. Except that it was poor judgmnt and luck that carried the day.

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KR,  IF you are in marginal conditions then you could be in strife and there's plenty of examples of that happening. You can get weather updates in flight. The specifics you give are a fair case in point but IF WMD is not suitable many of the other places you mention are not likely to be either as they all share the same conditions more or less. It's unlikely your area forecast would have been good either. You always need an escape route/possibility which might be Mudgee provided you haven't left it too late in the day, then I'd be talking to Willy tower about a talked down into there and do the paperwork later.. At least you are still alive. East of the divide around there can be tricky. Nev

Edited by facthunter
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Totally agree @facthunter, I didn't articulate it clearly, but I'd meant that example to be in the context of planning, not actually flying it.

 

If I've read the AIP right and there's no other clause hidden away, then I'd need to plan to Cessnock, and have enough fuel to divert to Taree/Bankstown if necessary. IF you're only TAS'ing 120KTAS that's another 45 minutes or so of fuel you'll need to carry just because you can't use the GAF.🤬 Same for Bankstown itself if it were below the Alternate Minima, you could consider an alternate as Sydney, Maitland or Wollongong, there aren't a lot of options, even though you might be able to  use Wedderburn, Warnervale, Katoomba, Somersby yadda yadda, they don't have a TAF so you need one that does...

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Maybe it goes back to ALA's and what WE can use is less stringent. I still suggest the area forecast should cover it in a practical sense Interesting if you were in a check situation . Suitable includes x wind limits and periods of bad weather which may be covered by holding (sometimes).

  Cloud extent level distance and vis are what defines VFR and all you need for landing is the extra of the wind being suitable for your ops at your ETA plus and minus a period of buffer..There can be local effects at some places but I think that's making it more complex than we have to. IF you have made contact with the aerodrome owner as is often required you might get weather and conditions information from him/her/them. That would be of considerable value I would think. When I've been going to some remote and "unfriendly" areas I've often gotten reports from people I know in the area on the way, before I leave and commit myself to going  I've felt that cover s it at the time..Nev

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