VMC requirement more restrictive in controlled airsapce?
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VMC requirement more restrictive in controlled airsapce?
Can anyone please explain why the VMC requirement is more resrictive inside controlled airspace than when OCTA?
This makes absolutely no sense to me. When OCTA, with no control or radar services, you are able to fly with your tail fin in the cloud as you are "VMC". But as soon as you enter an area where you now have control and a radar service providing deconfliction and traffic awareness, then you suddenly need 1000' of vertical separation from cloud?
This limits low level operations substantially, especially when looking at the legality behind the IFR visual departure. According to AIP / FIHA, you cannot do a visual departure IFR unless you can maintain VMC until you reach LSALT? This makes no sense either. What if you don't even want to reach LSALT? You are IFR, as long as you can avoid the ground yourself, this should be permitted.
If anyone has info on how this VMC requirement inside controlled airsapce (specifically in regard to lower level ops) was determined, I would be very interested.
This makes absolutely no sense to me. When OCTA, with no control or radar services, you are able to fly with your tail fin in the cloud as you are "VMC". But as soon as you enter an area where you now have control and a radar service providing deconfliction and traffic awareness, then you suddenly need 1000' of vertical separation from cloud?
This limits low level operations substantially, especially when looking at the legality behind the IFR visual departure. According to AIP / FIHA, you cannot do a visual departure IFR unless you can maintain VMC until you reach LSALT? This makes no sense either. What if you don't even want to reach LSALT? You are IFR, as long as you can avoid the ground yourself, this should be permitted.
If anyone has info on how this VMC requirement inside controlled airsapce (specifically in regard to lower level ops) was determined, I would be very interested.
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I can understand the lateral requirement here, but not the vertical. If there is a solid base at 800' AGL, you can't stay beneath it either VFR or IFR, (but SVFR you can). OCTA you can though.
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For all VFR operations in Class C, D, E and G (OCTA) the 1000ft vertically and 1500m horizontally rule applies. The visibility criteria is greater above A100.
Only in Class G you can operate at or below 3,000 FT AMSL or 1,000 FT AGL whichever is the higher clear of cloud. Also, GAAP aerodromes VMC criteria is clear of cloud also.
Maybe the low level G stuff is to facilitate ag airwork or something.
And ATC are not the police, nor can they tell how close you are to cloud, so it is up to the pilot in command to follow the rule.
Check AIP ENR 1.2-2 for the information.
Cheers,
NFR
Only in Class G you can operate at or below 3,000 FT AMSL or 1,000 FT AGL whichever is the higher clear of cloud. Also, GAAP aerodromes VMC criteria is clear of cloud also.
Maybe the low level G stuff is to facilitate ag airwork or something.
And ATC are not the police, nor can they tell how close you are to cloud, so it is up to the pilot in command to follow the rule.
Check AIP ENR 1.2-2 for the information.
Cheers,
NFR
Last edited by No Further Requirements; 24th Mar 2009 at 05:30.
I always felt it was more to do with the nature of CTA areas being busier, thusly VFR pilots as they don't receive seperation from IFR aircraft need to have more of a buffer to help increase safety?
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AC,
I seem to recall someone posting some stuff about this back when the NAS [wash my mouth out with soap] threads were running.
I think it was something to do with the fact that IFR aircraft dropping through the bottom of cloud in 'controlled' airspace - particulary Class C and D - needed to have a little time to orientate themselves and start searching for conflicting VFR traffic. This was also why the speed restriction of 250kts below 10000 feet was introduced. It's a bit rough on the poor old IFR drivers if they drop out of cloud straight onto a Cessna 152 with it's tail sticking into the cloud!
You'd need to look back through the threads - but I think this is the reason. Also, I think it came from ICAO - not an Australian idea.
I seem to recall someone posting some stuff about this back when the NAS [wash my mouth out with soap] threads were running.
I think it was something to do with the fact that IFR aircraft dropping through the bottom of cloud in 'controlled' airspace - particulary Class C and D - needed to have a little time to orientate themselves and start searching for conflicting VFR traffic. This was also why the speed restriction of 250kts below 10000 feet was introduced. It's a bit rough on the poor old IFR drivers if they drop out of cloud straight onto a Cessna 152 with it's tail sticking into the cloud!
You'd need to look back through the threads - but I think this is the reason. Also, I think it came from ICAO - not an Australian idea.
Class G and CTAF VMC below 3000ft AMSL/1000ft AGL is to facilitate VFR operations. The likelyhood of an IFR aircraft operating in this zone en-route is not great and close to CTAF & GAAP they should be communicating via the radio, and highly alert to the possibility of VFR traffic. CTAF with high volume of IFR traffic will be upgraded to CTAF(R) and the carriage of radio becomes mandatory.
Class C is set up to facilitate higher rates of IFR so VMC (and therefor VFR flight) is more restrictive. VMC may be reduced via special VFR to allow a VFR flight to arrive/depart a control zone so long as it does not delay an IFR flight.
Class C is set up to facilitate higher rates of IFR so VMC (and therefor VFR flight) is more restrictive. VMC may be reduced via special VFR to allow a VFR flight to arrive/depart a control zone so long as it does not delay an IFR flight.
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I would like to thank NFR, Frink, and 43 inches for restating the rules and the obvious.
I was obviously not enquiring about what the rules are. I was enquiring as to why the VMC criteria are more restrictive and "safer" in a sanitised and supported environment (controlled airspace) as apposed to the 'anyone can be out here and not looking out the window' environment. I would have thought that in Class G airspace it would be more prudent to have more room between yourself and the surrounding cloud so that you can see who is out there, as ATC are providing any info.
The reason I am asking this question was because I was going to approach AIS about how this can be reviewed and possibly re-written, and wanted some feedback from other guys out there about the background reasoning.
As a regular low-level IFR operator, I find the regulations regarding the IFR visual departure uneccessarily restrictive, which can be linked back to the VMC criteria in controlled airspace, which is also uneccessarily restrictive.
Direct Anywhere raised a good point regarding 'ducking around cloud', but VFR pilots would still need to ask for the appropriate clearance if they were to 'duck around cloud' that is 1500m away to preserve VMC.
Thanks for the input Well Concerned. IFR aircraft OCTA would have the same issue though in regard to descending through the cloud base. And OCTA, they will not neccessarily get a 'heads up' that the traffic is there.
I was obviously not enquiring about what the rules are. I was enquiring as to why the VMC criteria are more restrictive and "safer" in a sanitised and supported environment (controlled airspace) as apposed to the 'anyone can be out here and not looking out the window' environment. I would have thought that in Class G airspace it would be more prudent to have more room between yourself and the surrounding cloud so that you can see who is out there, as ATC are providing any info.
The reason I am asking this question was because I was going to approach AIS about how this can be reviewed and possibly re-written, and wanted some feedback from other guys out there about the background reasoning.
As a regular low-level IFR operator, I find the regulations regarding the IFR visual departure uneccessarily restrictive, which can be linked back to the VMC criteria in controlled airspace, which is also uneccessarily restrictive.
Direct Anywhere raised a good point regarding 'ducking around cloud', but VFR pilots would still need to ask for the appropriate clearance if they were to 'duck around cloud' that is 1500m away to preserve VMC.
Thanks for the input Well Concerned. IFR aircraft OCTA would have the same issue though in regard to descending through the cloud base. And OCTA, they will not neccessarily get a 'heads up' that the traffic is there.
WELLCONCERNED, What's this washing your mouth out re NAS?
Then again we wouldn't want to copy one of the best and most proven airspace systems in the world, would we? One that is based on science- not perception!
Remember we designed the Nomad, they designed the 747.
We should resist change and stick with our 1930's British based system under all costs.
Like having RPT Jet Airline aircraft operating in radar covered terminal airspace at places like Proserpine and Ballina without any radar control service at all.
That is, we resist change until an accident and lost lives forces it on us.
Just like the past.
Then again we wouldn't want to copy one of the best and most proven airspace systems in the world, would we? One that is based on science- not perception!
Remember we designed the Nomad, they designed the 747.
We should resist change and stick with our 1930's British based system under all costs.
Like having RPT Jet Airline aircraft operating in radar covered terminal airspace at places like Proserpine and Ballina without any radar control service at all.
That is, we resist change until an accident and lost lives forces it on us.
Just like the past.
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Whilst on this topic if I may also digress a little....... how do others go when in VMC inside CTA and actually coming across IMC conditions? It *frequently* happens for me that I'm zooming along and very quickly come up upon some cloud and it sometimes happens quite quickly or I have time to go around it, but this would require loads of radio work on what may already be a congested frequency.
Would you just zoom on through it knowing that you'll come out the other side shortly?
Just keep going into temporary IMC, not mention it and not worry as you're not going to hit anyone / anything because you're in CTA under the assumption you'll come out the other side?
Would you call radar / centre and immediately ask for a change to clearance?
Make the diversion and then worry about calling when clear of cloud?
None of the above?
Hopefully this doesn't sound like a stupid question, but as I said it happens often as a VFR pilot in Vic around Melbourne and when you have to call urgently because you're only VFR it's like you're making a mountain out of a mole-hill.
Would you just zoom on through it knowing that you'll come out the other side shortly?
Just keep going into temporary IMC, not mention it and not worry as you're not going to hit anyone / anything because you're in CTA under the assumption you'll come out the other side?
Would you call radar / centre and immediately ask for a change to clearance?
Make the diversion and then worry about calling when clear of cloud?
None of the above?
Hopefully this doesn't sound like a stupid question, but as I said it happens often as a VFR pilot in Vic around Melbourne and when you have to call urgently because you're only VFR it's like you're making a mountain out of a mole-hill.
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XXX. May I ask how fast / slow you are going when this cloud 'comes upon you'?
Using a visibility requirement of 8km (approx 4 nm), you should be able to see that distance ahead, provided you are looking out the window. Even if you are travelling at 240kts, you would have at least 1 minute to realise that this cloud is approaching. That should be plenty of time for you to manv or liase with ATC to sort your clearance/tracking out.
If you are like most other VFR lighties and travelling at 100kts, then you will have even more time up your sleave.
Using a visibility requirement of 8km (approx 4 nm), you should be able to see that distance ahead, provided you are looking out the window. Even if you are travelling at 240kts, you would have at least 1 minute to realise that this cloud is approaching. That should be plenty of time for you to manv or liase with ATC to sort your clearance/tracking out.
If you are like most other VFR lighties and travelling at 100kts, then you will have even more time up your sleave.
As a VFR/IFR pilot operating in and out of Class C airspace all the time, you guys have me wondering if I am working in the same system as you!
anti casa - Please explain? When I depart on an IFR flightplan and am given a Visual Departure - I depart visually, but if given an IF Departure I fly that! Apart from a bit of a scramble to find the departure plate, what's the big deal?
XXX - I zoom along as quickly as most but I can't say I have ever had a cloud sneek up on me without time to request a level or track change - but maybe things are a bit quiter up here!
Dr
As a regular low-level IFR operator, I find the regulations regarding the IFR visual departure uneccessarily restrictive
It *frequently* happens for me that I'm zooming along and very quickly come up upon some cloud and it sometimes happens quite quickly
Dr
VH-XXX,
I sincerely hope you and others don't consider these options:
or
I realise you didn't say that you did, however it concerns me that these may be options considered by VFR pilots. It's a great way to kill yourself.
There will be many times when you don't, but IFR ratings are issued for a reason. Perhaps the VFR aircraft you are flying is not IFR approved.
I assume you realise these options are not a safe path to take. Is it really such a big deal to contact ATC for tracking changes/climb/descent etc. I suggest that entry into IMC is a PAN or perhaps even MAYDAY for a VFR pilot - that'll get their attention.
Safe flying.
Joe Lighty
I sincerely hope you and others don't consider these options:
Would you just zoom on through it knowing that you'll come out the other side shortly?
Just keep going into temporary IMC, not mention it and not worry as you're not going to hit anyone / anything because you're in CTA under the assumption you'll come out the other side?
There will be many times when you don't, but IFR ratings are issued for a reason. Perhaps the VFR aircraft you are flying is not IFR approved.
I assume you realise these options are not a safe path to take. Is it really such a big deal to contact ATC for tracking changes/climb/descent etc. I suggest that entry into IMC is a PAN or perhaps even MAYDAY for a VFR pilot - that'll get their attention.
Safe flying.
Joe Lighty
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According to AIP/FIHA, in order for a pilot to conduct a visual departure IFR, you are supposed to maintain VMC (1000' vertical etc...) until above LSALT.
What if I don't want to get above LSALT, and would like to remain under the ceiling? It would make sense to get a clearance of "maintain not above 1500' visual" meaning the pilot accepts responsibility for terrain clearance. But this is not permitted IAW AIP. ATC does give it to you though, as they are not aware of your VMC/IMC status.
This is my gripe with the VMC criteria inside controlled airspace.
I am IFR but need to maintain VMC!
What if I don't want to get above LSALT, and would like to remain under the ceiling? It would make sense to get a clearance of "maintain not above 1500' visual" meaning the pilot accepts responsibility for terrain clearance. But this is not permitted IAW AIP. ATC does give it to you though, as they are not aware of your VMC/IMC status.
This is my gripe with the VMC criteria inside controlled airspace.
I am IFR but need to maintain VMC!
Hmmmm! You learn something new every day!
You can't fly VFR in Class C airspace if the cloudbase is , say, 1100' - unless on a Special VFR clearance!
Stupid! You know what happens to stupid rules!
Dr
You can't fly VFR in Class C airspace if the cloudbase is , say, 1100' - unless on a Special VFR clearance!
Stupid! You know what happens to stupid rules!
Dr
anti-casa, the obvious is sometimes what governs the rules. Class C is set up for IFR so they do not particularly want VFR or IFR below LSALT/MSA/MVA which can become unpredictable if conditions deteriorate. The current rules for VMC and special VFR give the controller choice to reject VFR flights when conditions are marginal and workload high. As far as wanting to proceed in VMC below LSALT why not just accept the instrument departure procedure and then request the visual level once airborne (If in VMC). The AIP rules only govern the assigning of or request of a visual departure before take-off, once inflight you must only maintain VMC for the level chosen.
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Dr. I'm in Melbourne. We probably get more cloud around our CBD than you do and our airwaves get quite congested around Melbourne. Remember, people move to QLD to retire. It can literally be so busy you can barely get a word in and I shudder to think what would happen every time I'm operating on a clearance and I call Pan or Mayday every time a little bit of cloud comes my way.
Moorabbin GAAP had a cloud base of 1,000ft on Sunday and Special VFR ops were in force.
Joseph, et, al, let's assume now that I am IFR rated and in an appropriately equipped IFR rated aircraft. Does that change things - I would think not, you're still operating as VFR. Surely you can't just keep going into cloud without calling?
Moorabbin GAAP had a cloud base of 1,000ft on Sunday and Special VFR ops were in force.
Joseph, et, al, let's assume now that I am IFR rated and in an appropriately equipped IFR rated aircraft. Does that change things - I would think not, you're still operating as VFR. Surely you can't just keep going into cloud without calling?
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Gentlemen,
Please correct me if I am wrong, but don't the rules of CTA allow the pilot to make a deviation from the clearance for the safe conduct of the flight and inform ATC afterwards? If that is the deal, then if you couldn't get on the frequency due congestion, the prudent path would be to do what you needed to remain in VMC and then tell ATC ASAP when you could get the call in.
Walrus
Please correct me if I am wrong, but don't the rules of CTA allow the pilot to make a deviation from the clearance for the safe conduct of the flight and inform ATC afterwards? If that is the deal, then if you couldn't get on the frequency due congestion, the prudent path would be to do what you needed to remain in VMC and then tell ATC ASAP when you could get the call in.
Walrus
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Or one could actually read the forecast and decide whether or not to plan IFR or (if not instrument rated) not go at all before getting airborne! I believe it's called preparation.
However judging from some of the comments here and the regular accidents caused by non-instrument rated pilots flying into cloud and killing themselves, there doesn't seem to be much respect for the rules in this country.
VMC are the way they are for a reason.
However judging from some of the comments here and the regular accidents caused by non-instrument rated pilots flying into cloud and killing themselves, there doesn't seem to be much respect for the rules in this country.
VMC are the way they are for a reason.