Holding at IAF of RNAV
Thread Starter
Holding at IAF of RNAV
Am keen to hear opinions (and actual references) in regards to holding at the initial of an RNAV (not published for holding) at a referenced MSA.
Have spoken to a local CASA FOI, seems to think it is NOT on at all because it is not a surveyed area. Fair enough, but if I am referencing a charted GRID or MSA with a GPS and requesting traffic from ATC why not?
Had a good look and I cant find anything on it...
Have spoken to a local CASA FOI, seems to think it is NOT on at all because it is not a surveyed area. Fair enough, but if I am referencing a charted GRID or MSA with a GPS and requesting traffic from ATC why not?
Had a good look and I cant find anything on it...
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The purpose of surveying a published holding area is to ensure that terrain clearance is achieved for the (surprisingly large) volume taken up by a holding pattern with all possible entries and all assumed winds, at maximum permitted IAS. It's expensive, but done to allow holding below Grid LSALT or MSA.
If you're holding above minimum safe altitude (MSA or whatever) and have accounted for maximum GPS error and the maximum size of the hold with the wind of the day, then it's safe. But make sure that you're far enough inside the MSA boundaries to make your MSA still valid even with all these cumulative error margins.
Pages GEN 3.3 -15 to -18 apply. Paragraphs 4.3, 4.6 and 4.9 would seem especially relevant to an unpublished GPS holding pattern.
Cheers, O8
If you're holding above minimum safe altitude (MSA or whatever) and have accounted for maximum GPS error and the maximum size of the hold with the wind of the day, then it's safe. But make sure that you're far enough inside the MSA boundaries to make your MSA still valid even with all these cumulative error margins.
Pages GEN 3.3 -15 to -18 apply. Paragraphs 4.3, 4.6 and 4.9 would seem especially relevant to an unpublished GPS holding pattern.
Cheers, O8
Couple of different thoughts on this.....
First, with my procedure design hat on. Holds are placed and protected not just to avoid terrain. There may be other considerations, like deconfliction with holding patterns for other procedures or clearance from other aerodromes and traffic. So from this point of view I would say it is a good idea to hold only where there is a published holding pattern.
From a pilot point of view. If you are within the 25nm MSA and can garauntee you will stay there and separate from other aircraft, then you are allowed to manouver as required within the MSA area at the MSA. After all, that is what the MSA is designed for.
In the world of litigation you should consider the following. If you do decide to hold away from a published holding pattern and you hit something or someone and cause damage. At the subsequent coroners enquiry the prime question will be; Why did you hold at an unpublished holding point? In thinking about your answer to this question add "Your Honour" to the end and see if you can come with an answer that doesn't sound irresponsible.
Food for thought....personally I'd be sticking the published patterns.
First, with my procedure design hat on. Holds are placed and protected not just to avoid terrain. There may be other considerations, like deconfliction with holding patterns for other procedures or clearance from other aerodromes and traffic. So from this point of view I would say it is a good idea to hold only where there is a published holding pattern.
From a pilot point of view. If you are within the 25nm MSA and can garauntee you will stay there and separate from other aircraft, then you are allowed to manouver as required within the MSA area at the MSA. After all, that is what the MSA is designed for.
In the world of litigation you should consider the following. If you do decide to hold away from a published holding pattern and you hit something or someone and cause damage. At the subsequent coroners enquiry the prime question will be; Why did you hold at an unpublished holding point? In thinking about your answer to this question add "Your Honour" to the end and see if you can come with an answer that doesn't sound irresponsible.
Food for thought....personally I'd be sticking the published patterns.
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If you're in a high performance aircraft your hold may take you over the instrument approach, or the missed approach.
If there are other aircraft using the approach you could become a hiderence to their operation.
If you have an emergency, all bets are off. Do what you need to do to satisfy the best outcome for your passengers and company asset.
If there are other aircraft using the approach you could become a hiderence to their operation.
If you have an emergency, all bets are off. Do what you need to do to satisfy the best outcome for your passengers and company asset.
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Bladeangle, Feel free to hold at the IAF and make your own holding pattern...as long as the pattern is above the MSA or Grid there will be no problems.
However, if the MSA (unlikely) or Grid is at an altitude that would require you to do a steep descent after leaving the IAF, that would defeat the purpose of a stabilised approach. If that's the case just stick to the published pattern.
For what it's worth, we make our own holding patterns in the simulator quite often !!
Spock
However, if the MSA (unlikely) or Grid is at an altitude that would require you to do a steep descent after leaving the IAF, that would defeat the purpose of a stabilised approach. If that's the case just stick to the published pattern.
For what it's worth, we make our own holding patterns in the simulator quite often !!
Spock
Thread Starter
Thanks for the input thus far guys.
Confirmed my thoughts on the subject. Some good points, especially on procedure design, eg missed approach.
As for the FOI, he purely said "you can not hold anywhere there is not a published holding pattern". I walked away from him at this point thinking he might have actually had some knowledge on the subject of flying.
You shouldn't really need to do a sector entry at an rnav unless you were holding, would be easier to simply manoeuvre so that you fall within the capture region of one of the IAF's.
Cheers BA.
Confirmed my thoughts on the subject. Some good points, especially on procedure design, eg missed approach.
As for the FOI, he purely said "you can not hold anywhere there is not a published holding pattern". I walked away from him at this point thinking he might have actually had some knowledge on the subject of flying.
You shouldn't really need to do a sector entry at an rnav unless you were holding, would be easier to simply manoeuvre so that you fall within the capture region of one of the IAF's.
Cheers BA.
Nitpicker, ask the blokes that held in the missed approach at Launceston a few years ago if they can 'hold anywhere'. After coming face to face with another aeroplane I'm not sure they will agree with you.
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If centre clear you for holding, then it becomes centres responsibility to clear you from other traffic, and (if in CTA) terrain. If you are above MSA then fill your boots, because centre is looking out for you
But OCTA...different story. The responsibilities are now yours. Terrain is easy to clear from, as everyone has stated. But conflict with other traffic, holding patterns, approaches, etc...well thats not so easy to clear from.
Perfect example of this are the position of the holding patterns at Cootamundra and Wagga RNAV's. If you hold wherever you like there is a good chance you will be in conflict with approaches at the other airfield. Conflicting traffic will be on another freq...bit hard to say you can guarantee separation.
Again, ask the guys involved in the Launceston incident if they thought holding where they did was a good idea.
But OCTA...different story. The responsibilities are now yours. Terrain is easy to clear from, as everyone has stated. But conflict with other traffic, holding patterns, approaches, etc...well thats not so easy to clear from.
Perfect example of this are the position of the holding patterns at Cootamundra and Wagga RNAV's. If you hold wherever you like there is a good chance you will be in conflict with approaches at the other airfield. Conflicting traffic will be on another freq...bit hard to say you can guarantee separation.
Again, ask the guys involved in the Launceston incident if they thought holding where they did was a good idea.
Last edited by alphacentauri; 21st Nov 2012 at 01:30.
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Bladeangle
The FOI may have been referring to the new requirement for ATO's to only test holding patterns on a published holding pattern.
This is fairly new and is only relevant to initial and renewal tests. This is only for testing and nothing else..
Andy.
The FOI may have been referring to the new requirement for ATO's to only test holding patterns on a published holding pattern.
This is fairly new and is only relevant to initial and renewal tests. This is only for testing and nothing else..
Andy.
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from alphacentauri's post above
Your theory is great but the reality of most NDB and VOR approaches are designed that the aircraft carrying out a missed approach will fly straight through the published holding pattern at the same level as the minimum holding altitude (YMAY Rwy 25 VOR as an example)
Why is it ok to design that way for those but not for holding on an RNAV as you imply.
You can hold anywhere as long as it is above the MSA and you have to use common sense to overcome the design flaws in both published and random holding patterns to avoid others.
First, with my procedure design hat on. Holds are placed and protected not just to avoid terrain. There may be other considerations, like deconfliction with holding patterns for other procedures or clearance from other aerodromes and traffic. So from this point of view I would say it is a good idea to hold only where there is a published holding pattern.
Why is it ok to design that way for those but not for holding on an RNAV as you imply.
You can hold anywhere as long as it is above the MSA and you have to use common sense to overcome the design flaws in both published and random holding patterns to avoid others.
Yeah ok....I'll bite
With the YMAY VOR 25 plate open in front of me, the difference in height between min holding alt and minima at the Mapt is 2200ft. The missed approach gradient is only 2.5%, where you will reach 3400ft approximately 14nm away from the airfield.
Exactly how much clearance do you want?
With the YMAY VOR 25 plate open in front of me, the difference in height between min holding alt and minima at the Mapt is 2200ft. The missed approach gradient is only 2.5%, where you will reach 3400ft approximately 14nm away from the airfield.
Exactly how much clearance do you want?
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OK, now apply your theory to YMIA VOR Rwy 09 for a cat C a/c.
The holding should have been designed as a left pattern (still 290 inbound) to cater for missed approach, right works in (office) theory eh !
There are dozens designed this way when a little bit of reality consideration would have shown the the design flaws and hopefully the simple fix !
Please don't try to tell me that I can't use common sense and fly a left hold to avoid an a/c ahead on the approach if they go around.
The holding should have been designed as a left pattern (still 290 inbound) to cater for missed approach, right works in (office) theory eh !
There are dozens designed this way when a little bit of reality consideration would have shown the the design flaws and hopefully the simple fix !
Please don't try to tell me that I can't use common sense and fly a left hold to avoid an a/c ahead on the approach if they go around.
Last edited by Captahab; 22nd Nov 2012 at 03:09.
You'd have to climb at 5.5% to conflict with aircraft at the start alt in the pattern.
But if you have just left the aid at the start alt, only a foolish person above you in the pattern or joining the pattern would join at the altitude you have just left, especially as you would only be 300ft below them as turning inbound.
According to everyone else on here you can hold anywhere....But let me ask you a question. If you do fly a left holding pattern and you hit someone/something, how are you going to defend youself. Does your ops manual include CASA approval to change the published direction of holding patterns as you see fit?
The turn direction of the pattern at Mildura would only have made a marginally better conflict with the missed approach....the holding pattern protection is huge and the change is conflict would be minimal
But if you have just left the aid at the start alt, only a foolish person above you in the pattern or joining the pattern would join at the altitude you have just left, especially as you would only be 300ft below them as turning inbound.
Please don't try to tell me that I can't use common sense and fly a left hold to avoid an a/c ahead on the approach if they go around.
The turn direction of the pattern at Mildura would only have made a marginally better conflict with the missed approach....the holding pattern protection is huge and the change is conflict would be minimal
Last edited by alphacentauri; 22nd Nov 2012 at 03:16.