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a7ala
Topic Author
Posts: 438
Joined: Sun Jan 04, 2015 10:27 pm

Curved runway starter extensions

Thu Jan 20, 2022 3:16 am

Hi all, do the rules allow for a runway starter extension to be curved?

The scenario I am thinking of is a runway with a starter extension which begins from the parallel taxiway and joins at the threshold. If the distance between the taxiway centreline and runway centreline is 100m then you could create a 150m curve effectively giving an additional 50m in TORA.

Does anyone know if the rules allow, and if so has any airport done it and airlines using it?

Thanks
 
GalaxyFlyer
Posts: 9176
Joined: Fri Jan 01, 2016 4:44 am

Re: Curved runway starter extensions

Thu Jan 20, 2022 3:35 am

There’s no “starter”, it’s either runway, stressed for aircraft operations or there’s overrun that’s not useable for take-off.
 
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Starlionblue
Posts: 21060
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Re: Curved runway starter extensions

Thu Jan 20, 2022 4:16 am

There are certainly curved runways, but they're more normally associated with bush flying.

Behold Kiwirok in Papua.

Image
 
aeropix
Posts: 291
Joined: Mon Jun 06, 2005 2:08 pm

Re: Curved runway starter extensions

Thu Jan 20, 2022 4:24 am

Starlionblue wrote:
There are certainly curved runways, but they're more normally associated with bush flying.

Behold Kiwirok in Papua.



Wow that must be one way in / one way out operation.
 
aeropix
Posts: 291
Joined: Mon Jun 06, 2005 2:08 pm

Re: Curved runway starter extensions

Thu Jan 20, 2022 4:26 am

GalaxyFlyer wrote:
There’s no “starter”, it’s either runway, stressed for aircraft operations or there’s overrun that’s not useable for take-off.


Well, the starter extension concept is a real thing, just not in all countries.

See https://www.airliners.net/forum/viewtopic.php?f=5&t=1429653
 
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Starlionblue
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Joined: Fri Feb 27, 2004 9:54 pm

Re: Curved runway starter extensions

Thu Jan 20, 2022 4:29 am

aeropix wrote:
Starlionblue wrote:
There are certainly curved runways, but they're more normally associated with bush flying.

Behold Kiwirok in Papua.



Wow that must be one way in / one way out operation.


Like at many such runways in Papua, I think you always land uphill and takeoff downhill.
 
GalaxyFlyer
Posts: 9176
Joined: Fri Jan 01, 2016 4:44 am

Re: Curved runway starter extensions

Thu Jan 20, 2022 2:32 pm

Check out Missionary Bush Pilot on You Tube. Kiwirok is LGA In comparison to some of the ones Ryan flies in and out of.
 
GalaxyFlyer
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Joined: Fri Jan 01, 2016 4:44 am

Re: Curved runway starter extensions

Thu Jan 20, 2022 3:11 pm

Now I look at the link, RAF Mildenhall had something like a starter extension—performance planning could use one overrun for take-off planning, but not the other end. IIRC, 9227’ of official runway plus two overruns of 1,000’ each. TORA/TODA/ASRA could be 10,227’ but not 11,227’. The overrun could be used only if mission required it, so not normally planned. For the life of me, I never understood it. It was also the only place I saw it.
 
bluecrew
Posts: 232
Joined: Sun Apr 20, 2014 3:13 am

Re: Curved runway starter extensions

Thu Jan 20, 2022 5:16 pm

a7ala wrote:
Hi all, do the rules allow for a runway starter extension to be curved?

The scenario I am thinking of is a runway with a starter extension which begins from the parallel taxiway and joins at the threshold. If the distance between the taxiway centreline and runway centreline is 100m then you could create a 150m curve effectively giving an additional 50m in TORA.

Does anyone know if the rules allow, and if so has any airport done it and airlines using it?

Thanks

There are plenty of curved taxiways that lead on to a runway, not everything is 90 degrees. Quick search and I can't seem to find one, but looking at ex-military fields would be a best bet.

The utility would be hampered by nosewheel steering effectiveness and using the rudder for this if you need it. If you're joining the runway at 40 knots or above with full power set, it's going to be pretty uncomfortable in the back as you line up, and there's a good chance you'll "miss." For the marginal increase in runway capacity (if any) you'd be introducing a lot of threats that just wouldn't be worth it.
 
Cubsrule
Posts: 15627
Joined: Sat May 15, 2004 12:13 pm

Re: Curved runway starter extensions

Thu Jan 20, 2022 5:22 pm

bluecrew wrote:
a7ala wrote:
Hi all, do the rules allow for a runway starter extension to be curved?

The scenario I am thinking of is a runway with a starter extension which begins from the parallel taxiway and joins at the threshold. If the distance between the taxiway centreline and runway centreline is 100m then you could create a 150m curve effectively giving an additional 50m in TORA.

Does anyone know if the rules allow, and if so has any airport done it and airlines using it?

Thanks

There are plenty of curved taxiways that lead on to a runway, not everything is 90 degrees. Quick search and I can't seem to find one, but looking at ex-military fields would be a best bet.

The utility would be hampered by nosewheel steering effectiveness and using the rudder for this if you need it. If you're joining the runway at 40 knots or above with full power set, it's going to be pretty uncomfortable in the back as you line up, and there's a good chance you'll "miss." For the marginal increase in runway capacity (if any) you'd be introducing a lot of threats that just wouldn't be worth it.


Are you thinking of something like V at BWI? It's not used much because an intersection departure on 28 from U1 gives 9,802 feet of runway but it seems to be what you are describing.
 
a7ala
Topic Author
Posts: 438
Joined: Sun Jan 04, 2015 10:27 pm

Re: Curved runway starter extensions

Thu Jan 20, 2022 7:48 pm

Starter extensions as I have seen them tend to get used when the runway length is constrained and the runway safety area (RESA) is built to a higher quality to allow the takeoff roll to start from as a starter extension. So the RESA length can be used as additional TORA at the starting end only.

My question was really around whether additional TORA could be created by using the distance between the Taxiway and runway, I guess there are two possibilities:

1. You could have a curved taxiway linking into the runway with the starter extension beginning on the taxiway - so if the separation of the two was 100m then using a quarter the circumference of a circle (around 150m) you could created an additional 50m of TORA to be used in the declared distance

2. If a curved starter extension wasnt allowed, you could still have a curved taxiway but aircraft could start the roll from the taxiway and then not include lune up allowance in their performance calculations.
 
GalaxyFlyer
Posts: 9176
Joined: Fri Jan 01, 2016 4:44 am

Re: Curved runway starter extensions

Thu Jan 20, 2022 9:59 pm

The line-up allowance is rarely much different the the plane’s length. We used 250’ in the C-5 and 100’ in the Global. A curving entry onto the runway p, even if rolling, is going to use more the TORA than just lining up from 90 degree turn at the first brick. I’ve never seen anything used in Perf A calculations than the declared distances on the runway.
 
bluecrew
Posts: 232
Joined: Sun Apr 20, 2014 3:13 am

Re: Curved runway starter extensions

Thu Jan 20, 2022 11:19 pm

Cubsrule wrote:
bluecrew wrote:
a7ala wrote:
Hi all, do the rules allow for a runway starter extension to be curved?

The scenario I am thinking of is a runway with a starter extension which begins from the parallel taxiway and joins at the threshold. If the distance between the taxiway centreline and runway centreline is 100m then you could create a 150m curve effectively giving an additional 50m in TORA.

Does anyone know if the rules allow, and if so has any airport done it and airlines using it?

Thanks

There are plenty of curved taxiways that lead on to a runway, not everything is 90 degrees. Quick search and I can't seem to find one, but looking at ex-military fields would be a best bet.

The utility would be hampered by nosewheel steering effectiveness and using the rudder for this if you need it. If you're joining the runway at 40 knots or above with full power set, it's going to be pretty uncomfortable in the back as you line up, and there's a good chance you'll "miss." For the marginal increase in runway capacity (if any) you'd be introducing a lot of threats that just wouldn't be worth it.


Are you thinking of something like V at BWI? It's not used much because an intersection departure on 28 from U1 gives 9,802 feet of runway but it seems to be what you are describing.

Taxiway B North at DMK kind of curves in towards 21R like a highspeed leading on to the runway. (I think it's a military thing but I could be wrong)
I've only ever flown in and out a handful of times so I have no idea if they even use it.
That's kind of what I have in mind from what the OP stated, like it might look like that. It wouldn't really have much of a point though... we're talking maybe 50 extra feet usable in TORA distance if you could include it.
 
DH106
Posts: 702
Joined: Wed Jun 15, 2005 5:32 pm

Re: Curved runway starter extensions

Fri Jan 21, 2022 9:55 am

I think Brooklands airfield in the UK had an offset starter extension.
In the 1960's, Vickers manufactured the VC-10 there, and since the runway was < 4000 feet, each new VC-10 was required to use the starter extension to depart to the nearby Wisley airfield (which had a longer runway) for final fitting out.
 
tommy1808
Posts: 14893
Joined: Thu Nov 21, 2013 3:24 pm

Re: Curved runway starter extensions

Mon Jan 24, 2022 10:50 am

GalaxyFlyer wrote:
Now I look at the link, RAF Mildenhall had something like a starter extension—performance planning could use one overrun for take-off planning, but not the other end. IIRC, 9227’ of official runway plus two overruns of 1,000’ each. TORA/TODA/ASRA could be 10,227’ but not 11,227’. The overrun could be used only if mission required it, so not normally planned. For the life of me, I never understood it. It was also the only place I saw it.


KEL airport comes to mind.

Best regards
Thomas
 
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DL717
Posts: 2428
Joined: Wed May 23, 2018 10:53 pm

Re: Curved runway starter extensions

Wed Feb 09, 2022 3:20 am

a7ala wrote:
Hi all, do the rules allow for a runway starter extension to be curved?

The scenario I am thinking of is a runway with a starter extension which begins from the parallel taxiway and joins at the threshold. If the distance between the taxiway centreline and runway centreline is 100m then you could create a 150m curve effectively giving an additional 50m in TORA.

Does anyone know if the rules allow, and if so has any airport done it and airlines using it?

Thanks


In the US, they are no longer allowed and airports should be removing them if they haven’t already. Incursion prevention.

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