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Author Topic: Pax limits due to runway that don't jive.  (Read 995 times)

LuckyLibra

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Pax limits due to runway that don't jive.
« on: July 13, 2011, 08:33:35 AM »
I have 3 767-200s, let's call them A, B, and C. All have the same standard seating: 192/18.
They are flying out of SBSP, which has a runway of 1940m. They are all flying the same routes -- it is 197 nm.

A: runway requirement of 2130m. +15 tons weight variant. Has a range of 3770nm. No pax restrictions.
B: runway requirement of 1810m. standard weight variant. Has a range of 2300nm. Limited to 147 pax.
C: runway requirement of 1870m. +8.2 tons weight variant. Has a range of 3190nm. Limited to 176 pax.

I do not understand! If B & C have runway requirements of less than 1900m, but the runway is longer than 1900m -- why are they being limited?

And they are all flying very short routes, so they should not be carrying much fuel, and therefore runway length not really an issue, right?

Please help!

Offline alexgv1

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Re: Pax limits due to runway that don't jive.
« Reply #1 on: July 13, 2011, 09:14:20 AM »
Hi luckylibra,

Whats the destination runway length? Maybe they are being payload restricted on the return leg.
CEO of South Where Airlines (SWA|WH)

Offline swiftus27

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Re: Pax limits due to runway that don't jive.
« Reply #2 on: July 13, 2011, 11:29:13 AM »
Sao Paulo to Rio is 197nm...  so that must be it

The runway at SBRJ is 1320m..

So that's your answer.

Offline Sami

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Re: Pax limits due to runway that don't jive.
« Reply #3 on: July 13, 2011, 11:32:08 AM »
A bug report on this exists: http://www.airwaysim.com/forum/index.php/topic,14860.0.html

ie. the bit unlogical differences between same model aircraft with different MTOW.   Though not entirely sure if it's the same issue as here but sounds like it.

And like previous poster noted the runway at destination is seriously short, and actually the B767 should be able to operate there as that is seriously tight.

Offline swiftus27

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Re: Pax limits due to runway that don't jive.
« Reply #4 on: July 13, 2011, 11:45:53 AM »
A bug report on this exists: http://www.airwaysim.com/forum/index.php/topic,14860.0.html

ie. the bit unlogical differences between same model aircraft with different MTOW.   Though not entirely sure if it's the same issue as here but sounds like it.

And like previous poster noted the runway at destination is seriously short, and actually the B767 should be able to operate there as that is seriously tight.

1320m is a seriously short runway for a 767 to be landing at.  Heck, that's much shorter than the field I practice at KBKL (1889m)...  And they FREAK out whenever the air show comes and they land some serious widebodies there.

Offline Sami

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Re: Pax limits due to runway that don't jive.
« Reply #5 on: July 13, 2011, 11:48:17 AM »
The system tries to calculate the minimum possible runway length for each model based on the MTOW runway requirement (ie. max power and minimum weight), but that's again a calculated figure only.

Have to check how close it comes to reality with 767.


edit: Boeing's docs say that B767-300 with CF6 engines has the takeoff length of approx 1300-1350 meters when day is standard (ISA+15) and runway is at sea level and a/c weight is 115tn kg / 250tn lbs.

Empty weight (OEW) is 84.5tn kg for standard variant, so you can have 30,5tn kg payload and fuel. Fuel needed for 200nm sector + reserves would be let's say 5000 kg, you have 25tn payload left which allows still quite many max... Not sure if that calculation was correct though :p
« Last Edit: July 13, 2011, 12:07:13 PM by sami »

LuckyLibra

  • Former member
Re: Pax limits due to runway that don't jive.
« Reply #6 on: July 13, 2011, 02:03:13 PM »
Ok. Thanks... not sure how I missed that... nor why I have 767's inside Brazil...  :-\

Offline LemonButt

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Re: Pax limits due to runway that don't jive.
« Reply #7 on: July 13, 2011, 02:18:10 PM »
A: runway requirement of 2130m. +15 tons weight variant. Has a range of 3770nm. No pax restrictions.
B: runway requirement of 1810m. standard weight variant. Has a range of 2300nm. Limited to 147 pax.
C: runway requirement of 1870m. +8.2 tons weight variant. Has a range of 3190nm. Limited to 176 pax.

My simple answer would be that all 767 in the game have the same runway requirement, but the increased MTOW variants have engines that can deliver more thrust (to get a heavier plane with same wing area into the air using the same amount of runway).  Thus the longer range variants can carry more pax and less fuel on those short hops.

Offline swiftus27

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Re: Pax limits due to runway that don't jive.
« Reply #8 on: July 13, 2011, 03:17:05 PM »
Lemon, it was the destination runway not the engines in this case.

Offline JumboShrimp

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Re: Pax limits due to runway that don't jive.
« Reply #9 on: July 13, 2011, 03:23:42 PM »
Lemon, it was the destination runway not the engines in this case.

True, it was the destination runway that was limiting the pax, but the combination of MTOW and engines that was responsible for limits to be different.

Offline swiftus27

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Re: Pax limits due to runway that don't jive.
« Reply #10 on: July 13, 2011, 03:33:52 PM »
I see what you're saying, now.  Yes, this is the reason in this case. 

 

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