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Old 6th Dec 2012, 21:49   #1 (permalink)
 
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Holding point inside the runway strip?

Hi all, Can a holding point of a runway be inside the runway strip?

For example, I measured in google earth the holding point from runway 23 at LSGG and is at 90 meters from the centre line of the runway.

The Cat II holding line is at less than 150m of the centre line of the runway.

The AIP shows that the width of the runway strip is 300m.

I wouls like to know where can I find in ICAO or FAA a recommendation that explains a situation like this

Thanks in advance

Last edited by 7triple; 6th Dec 2012 at 22:21.
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Old 6th Dec 2012, 22:29   #2 (permalink)
 
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Its the same at EMA/EGNX. The Cat II/III holding points are in line with the Runway strip boundary (or further in the case of A2) however the Cat I holding points are aligned with the much closer Cleared & Graded area boundary (except A1 and G1 which are aligned with the other Cat I points)
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Old 7th Dec 2012, 03:57   #3 (permalink)
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ICAO Annex 14 will explain all.
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Old 7th Dec 2012, 10:53   #4 (permalink)
 
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Hi Burnie

Just checked EGNX and the AIP states "strip dimensions : width=300m" for rwy 09 and 27. Means 150m from each side of the centre line of the rwy.
Why, for example, G1, W2, H2, M2, S2 and W2, which are cat III holding points are at ~138m (less then 150m!!) ?
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Old 7th Dec 2012, 10:54   #5 (permalink)
 
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Didn't find answer to my question on annex 14.
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Old 7th Dec 2012, 11:44   #6 (permalink)
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Didn't find answer to my question on annex 14.
Trust me, it's there.

You need to understand what the various protection areas ans surfaces are for. From what I can recall without the books to hand, there should be no unnecessary obstacle within the strip. Aeroplanes at holding points are temporary obstacles and are treated differently. More importantly, the book tells you exactly what the minimum distance from centreline to holding point is for different categories of approach operations.
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Old 7th Dec 2012, 20:37   #7 (permalink)
 
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Just in the UK, CAP 168 Aerodrome Licensing applies. The UK files a difference to the Annex 14 distance of 150m choosing 137m as the CAT ll/lll hold.

Furthermore, where a holding point is at the start of TORA but there's a displaced landing threshold the UK permits a/c to wait even though an a/c tail could penetrate the Apps.

SGC
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Old 14th Jan 2013, 21:22   #8 (permalink)
 
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Hi again, back to the subject.

For example EGLL, runway 09L-27R, the runway strip is 300m large.

the cat II/III holding points are at ~137m.

If we check ICAO annex 14:

Objects on runway strips
Note. See 9.9 for information regarding siting of equipment and installations on runway strips.

3.4.6 Recommendation. An object situated on a runway strip which may endanger aeroplanes should be regarded as an obstacle and should, as far as practicable, be removed.

3.4.7 No fixed object, other than visual aids required for air navigation purposes and satisfying the relevant frangibility requirement in Chapter 5, shall be permitted on a runway strip:

a) within 77.5 m of the runway centre line of a precision approach runway category I, II or III where the code number is 4 and the code letter is F; or

b) within 60 m of the runway centre line of a precision approach runway category I, II or III where the code number is 3 or 4; or

c) within 45 m of the runway centre line of a precision approach runway category I where the code number is 1 or 2.

No mobile object shall be permitted on this part of the runway strip during the use of the runway for landing or take-off.

--------
If we look at the 3.4.7 a) no fixed object shall be permitted within 77.5 m of the runway centre line of a precision approach runway category I, II or III where the code number is 4 and the code letter is F right?
--------

And if we check ICAO Annex 10 it refers the "localizer sensitive area boundary" is at 137m.
http://img805.imageshack.us/img805/1...sitivearea.jpg

So, if this is all correct, an aircraft can penetrate the runway strip till the ILS sensitive ares boundary in low visibility operations, or in other words, can a stop bar cat II/III be placed inside the runway strip, but aligned with the ILS sensitive area boundary?

According to ICAO, an aircraft standing in a holding position, is considered as a mobile or fixed object? Or is it specified?

Thanks in advance
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Old 15th Jan 2013, 01:55   #9 (permalink)
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Like I said before, as far as I'm aware - but I can't think of a reference offhand - an aircraft under tow or power is not considered to be fixed obstacle. From my experience, Cat II/III runway holding points are generally put where they are to protect the ILS - that is to say, ILS safeguarding is the more demanding criterion for holding point siting.
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Old 15th Jan 2013, 07:38   #10 (permalink)
 
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ok,
The last paragraph of the Annex 14 - 3.4.7 refers: "No mobile object shall be permitted on this part of the runway strip during the use of the runway for landing or take-off."

In this case, if an aircraft standing at the holding point cat II/III is not considered as a fixed object, it shall be a mobile object, right?

Since the criterion of the ILS is more demanding, it means that an aircraft can be inside a runway strip.

Per definition (annex 14), a runway strip is a defined area including the runway and stopway, if provided, intended:
a) to reduce the risk of damage to aircraft running off a runway; and
b) to protect aircraft flying over it during take-off or landing operations.

So, theoretically, with runway (code 4E), according to 3.4.7 b), an aircraft can be inside the runway strip as close as 60m to the centre line. But, because the ILS sensitive area boundary is at 137m (>60m), the stop bars are sitting here.

In this case why the width of the runway strip is not 137m+137m=274m?
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Old 15th Jan 2013, 16:34   #11 (permalink)
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In this case why the width of the runway strip is not 137m+137m=274m?
I don't know - you'd need to ask one of the team who wrote that bit of Annex 14.

But I'll hazard a guess - no guarantee that I'm right though!

I think the problem is that you're comparing apples with oranges. The strip is there for the reasons that you cite. The location of the holding point is (usually) put where it is to protect the ILS signal.

I would imagine that the dimensions of the strip for each code of runway is based on a collision probability model for where an aircraft using the runway might end up if things go pear shaped (which is how many, if not all airborne separation standards are derived). I would expect that part of the model will consider the probability that an aircraft - of the the maximum size able to use the runway - will be at a holding point when another aircraft is using the runway, which often is going to be surprisingly small. This is all part of risk management - and as we all know, if you want aviation to be absolutely safe you have to stop the aeroplanes flying - but, the probability of a collision between one aircraft using the runway and another at a holding point is considered to be 'safe enough' using the strip dimensions in Annex 14. And experience would appear to bear this out.

Therefore - if you consider a holding point for a code 4E runway where the holding point does not lie within the ILS sensitive areas I would expect that holding point to be 60m from the centreline.

If the holding point somewhere is near an ILS sensitive area it will have to be located at the the sensitive area boundary which will probably put it further from the runway.

Imagine for one moment an ILS with a runway/taxiway configuration such that the aeroplanes are nowhere near a sensitive area at any point and the holding point location would be determined by the strip width only. Of course this is not going to be possible with an ILS but some of the 'new' precision approach systems don't have ground-based equipment or have a ground element that is not so sensitive to disruption. So a runway with a GPS-based approach could have holding points closer to the runway than one served by an ILS. In fact, better runway utilisation because aircraft will be able to line up more quickly is one of the operational benefits expected at high density airports if/when they move to GPS-based approaches.

Hope this makes sense! It's years since I dealt with this sort of stuff so my apologies for any inaccuracies (which will down to me) but I think the principle I've described is correct.
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