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VFR "over the top"

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Old 28th Feb 2007, 02:54
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VFR "over the top"

Question for the guru's,

I was asked about VFR over the top and couldn't answer properly because I'm not sure.

I thought VFR over the top was ok for 20 mins with a positive position fix. eg. Coming into Melbourne over the Kilmore gap, you know it's clear at Moorabbin, so at Kilmore you go over the cloud (with or without a clearance) and you don't see the cloud for say 20 - 25 minutes when you come back down again.

He says that VFR over the top over 4/8'ths or over is IFR no matter for how long. He also says that VFR over the top is always IFR and requires either a night rating (for the navaid's).

Any suggestions / references?
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Old 28th Feb 2007, 03:24
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1013.2

Sorry, I can't answer the technicalities of your question but I am sure someone in here will be able to.

However, as someone who has done a lot of "VFR on top", my advice to you is - DON'T DO IT - unless you have an IR in your back pocket.

Evenually you will get caught on top of 8/8th, struggling to find a way down.

I have been caught out twice when my destination had a CAVOK forcast - but required and approach to almost minima in order to get in.

FTDK
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Old 28th Feb 2007, 03:43
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VFR on top

Thats a pretty good question QNH, because I bet its not widely understood by many ....off the top of their head . Certainly I could not come up with a decent answer without looking at the regs etc. so here goes with a bit of piracy

VFR Flight Guide
D. VFR flight on top of more than 4/8 cloud is available provided that:
• VMC can be maintained during the entire flight, including climb,
cruise and descent.
• For VFR flight on top, the visual position fixing requirements of
section (B) or the other navigational requirements of AIP ENR 1.1
para.. 19.1 must be met
• Prior to conducting a VFR flight on top of more than 4/8 cloud, the
pilot in command must ensure that current forecasts and
observations (including those available in-flight observations) indicate
that conditions in the area of, and during the period of, the planned
descent below the cloud layer will permit the descent to be
conducted in VMC.
• The position at which descent below cloud is planned to occur must
be such as to enable continuation of the flight to the destination
and, if required, an alternate aerodrome in VMC (see Notes 1 and 3
- below).
E. When navigating by reference to radio navigation systems, the pilot in
command must obtain positive radio fixes at the intervals and by themethods prescribed in AIP ENR 1.1 para. 19.1 and 19.5.
F. The pilot in command of a VFR flight wishing to navigate by means of radio
navigation systems or any other means must indicate in the flight notification
only those radio navigation aids with which the aircraft is equipped and the
pilot is qualified to use (see Note 2)
G. VFR aeroplanes operating above FL200 must be equipped with an altimeter
calibrated to IFR standards and CASA approved is required for the flight.
Note 1: A pilot must not undertake a VFR flight on top of more than 4/8 cloud unless the aircraft is equipped with serviceable flight and navigation instruments as specified in CAO 20.18 Appendix IV (IFR and Night VFR).
Note 2: “Qualified” means the holder of an instrument rating or NVFR rating which is endorsed for the particular navigation aid or any private or higher category pilot who has received in-flight instruction from a qualified instructor in the use of the radio navigation aid as the sole means of navigation, and who is competent to navigate by use of the aid.
Note 3: Pilots are warned against initiating VFR-on-top when weather conditions are marginal. Before committing their flight to operating VFR-on-top they should be confident that meteorological information used is reliable and current, and clearly indicates that the entire flight will be able to be conducted in VMC.

And to save space wasting electrons and photons....CAO 20.18 App4 means an IFR spec aircraft.

So, it seems to me that when there is more than 4/8s of cloud you must be under it unless you have an IFR a/c and a rating to be able to use it too I dare say!!!

Unless anybody out there knows something I could not find......which is entirely possible!

J
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Old 28th Feb 2007, 04:32
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The way that I interpret those rules is that I can as a PPL fly VFR over the top using a VOR or GPS or similar if I have been shown how to use it by my instructor, but not necessarily have a NVFR or IFR rating as it doesn't say you need that.

What you will then need is an IFR aircraft with TSO'ed NavAids.

Seems a NVFR configured aircraft isn't able to go over 4/8ths.

It also reads to me that you only need these qualifications if you are navigating via radio devices, whereas if you have position fixes it's not required. So if it's only for a short period like I first suggested, then it's ok... I think.

A call to the Mrs. or Mistress at the other end to ensure blue sky would also be required.


Point taken Mr. Bonanza, however a call to the other end should help alleviate that problem on many occasions.
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Old 28th Feb 2007, 05:40
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I do agree with FTDK that VFR on top is not for the new or inexperienced VFR pilot.
Would also make sure of the good wx on the other side, or knowledge of excellent wx from your departure point.

Note 2 is worth looking at also, IFR, NVFR or suitably instructed and competent (I would suggest signed out?)

Last edited by scrambler; 28th Feb 2007 at 05:47. Reason: re reading of AIP
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Old 28th Feb 2007, 06:00
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Scrambler

It is my understanding that VFR on top is ok for less than 5/8s cloud i.e. 4/8 and below, but beyond that its for IFR guys only, no matter what!

Of course you could argue that if its solid cloud below you say a band of it yet within view say 10 or so miles ahead its 100% clear, well the skt is only 4/8 cloud, its just all packed into one patch........so then it is ok.

Another arguement might be its 100% below me and 0% above me, thats 50%

J
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Old 28th Feb 2007, 06:30
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For VFR flight on top, the visual position fixing requirements of
section (B) or the other navigational requirements of AIP ENR 1.1
para.. 19.1 must be met

means you can continue with visual navigating (positive postion fix every 30 mins), OR by the use of radio navaids (every 2 hours...)
it's just not considered "easy" to navigate visually above more than broken cloud
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Old 28th Feb 2007, 06:35
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VFR on top of even 8/8s is legal providing you meet the same position fixing requirements as for any other VFR flight, and that the aeroplane has the instruments for IFR or NVFR as mentioned in a post above.

So if you are navigating visually, you need to obtain a visual position fix every 30 minutes. This is what limits your ability to fly on top of overcast cloud. If you are able to navigate using radio navigation aids, you need to get a navaid position fix every 2 hours.

Other than the common sense limitations mentioned in the other posts, these are the legal requirements.
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Old 28th Feb 2007, 06:48
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Gear Off

So lets say there is a solid band of cloud only 20 miles accross, does that constitute 8/8's when its only that beneath you but clear ahead?

J
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Old 28th Feb 2007, 07:25
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Ask yourself this question. You are above 8 eigths, donk quits, you can't see the ground, where am I going to do a forced landing? You then descend through the cloud, basic IF comes into bat, then hmmm.... my AH isn't working because the vac pump has died with the engine so now you are descending into a black hole with limited panel. Forget it I say, I don't care what the AIP's say, I'll never do it unless I'm in a twin.

Cheers.
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Old 28th Feb 2007, 08:36
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beaver_rotate

Agree entirely, however thats not what QNH asked, and the rule book is what it is, setting boundaries, the prudent will operate inside them of course.

What got my attention after I posted what the rules say, is how do you define what is 8/8's on a given day over a given area.

Just a thought......dont use 100% vac pump instruments!

J
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Old 28th Feb 2007, 08:41
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Ok, well that mountain range is still on my left after 30 mins. Position fix number 1.

After 30 more minutes the mountain range is still on my left; position fix number 2.

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Old 28th Feb 2007, 09:39
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J430

Yeah know it wasn't what he asked, just my 2 cents.

"Just a thought......dont use 100% vac pump instruments!"

Bit hard when your in a 40 year old clapped out single!
 
Old 28th Feb 2007, 12:19
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Don't do it unless its really clear at the other end - mistreses and old mates don't count get yout observations from a met person tower or aviator any one elses opinion on the weather is unqualified and not worth the risk.

Last edited by Aerodynamisist; 28th Feb 2007 at 12:24. Reason: cut out non constructive coments
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Old 28th Feb 2007, 13:15
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i agree...

i fly and teach where we have a lot of cloud...

forget the % cloud and the rules where you live...

just do'nt do it...

you may get away with it for a while but it will get you one day... ( i hope not )...but...

the dean.
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Old 28th Feb 2007, 19:41
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The secret to any type of flying is to always have options, the more options you leave yourself, the more chance that the flight will end with a safe outcome. As a PPL I did many flights over cloud, however I found the trick was to always have an 'out'! My personal technique was to start my stopwatch as I went over cloud, if it got to 20 mins without me being able to descend in VMC, I would turn around and seek an alternative route.

Of course a few things come into play, it pays to have good local weather knowledge and always make sure you have an 'actual weather' from a 'qualified observer' for your destination, sadly a call to 'the misses' simply won't do, unless of course she works for the met beureau.

I personally would prefer to be on top of cloud than beneath it with the weather closing all around (provided there is a good supply of fuel), the only time I ever got myself into to trouble VFR, was pushing on under a low cloud base.

Cheers, HH.
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Old 28th Feb 2007, 23:39
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Howard,

I think you represent the greater proportion of us, many options, dont paint yourself into a corner etc. However the regs are as I posted, or at least I believe they are. In response to QNH's question I looked in the trusty VFR flight guide, and thats what I printed.

Now what you are saying is VFR on top is good, and it is, but it seems that if you have a C172 which is VFR only, and you are wanting to travel from A to B and as you say its cr@p underneth the cloud, the rules say you can't be above when its 5/8s or more, and it does not mention time in it at all.

You say as a PPL you did many flights over cloud so what is your take on the rules?


J
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Old 1st Mar 2007, 00:55
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I have no idea what the current rules are, and don't care any more cause I can just upgrade to IFR anyway.

but, in my VFR only days, my understanding was that you could legally fly VFR on top of solid overcast (8/8) if you were properly endorsed on an aid (NDB and/or VOR) that you could use for navigation - as per NVFR. The exception was in a control zone where you have to be able to navigate by visual reference to the ground.

I recall coming out of YIGM in a Mooney in about 1981, over the top of the cloud that inevitably sat on the mountain range to the west of YIGM, with TL Appr asking me for my position every 15 min or so, even though they had me identified on 2ndary surveillance radar. I remember thinking at the time that they were trying to catch me out. However I was tuned to TL VOR and DME so it was not a problem (26 years later I can probably safely confess to NOT being able to see the ground at the time).

One of the reasons for my caution above is that the forcast was for CAVOK at YEML where I was to refuel. When I got there is was solid overcast at about 1000' above the aerodrome. Fortunately I was able to find a hole about 20 nm to the west - which saved me much embarassment.

Had a similar situation arise a couple of years ago imbound to YROM in the Bo. On that occassion I was able to upgrade to IFR and fly the GPSRNAV Appr to get down.

FTDK

Last edited by ForkTailedDrKiller; 1st Mar 2007 at 01:59.
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Old 1st Mar 2007, 01:11
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hey guys I think you'll find that to use and therefore get a position fix with nav aids the pilot in command must be endorsed on those nav aids, that’s have those little letters scattered all over your licence, and you usually get those with a NVFR or IFR and CASA says that you cannot get a visual fix above 4/8 cloud therefore cannot plan to navigate via visual reference

so VFR on top is allowed if you are endorsed on available nav aids to get a correct position fix. and you are able to decend at your dest VMC
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Old 1st Mar 2007, 01:56
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to use and therefore get a position fix with nav aids the pilot in command must be endorsed on those nav aids
I think you'll find the term used is "qualified" to use the nav aids. As a PPL holder you would have completed the day VFR syllabus which includes "use of radio navigation aids"! As your CFI needs to certify that you have completed this syllabus prior to doing your practical test, I would say this qualifies you!

The PPL syllabus is available here!

I would like to add however I wouldn't suggest doing VFR on top without some additional Navaid training, I for one had no idea after the minimum two hours of the PPL, especially those bloody NDB's, they still get me every now and again even 24 years later.
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