MaverickM11
Topic Author
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Why do KE/CA fly around Himalayas to India?

Tue Feb 27, 2018 4:14 am

It seems like Northeast Asian carriers in China/Korea/Japan all fly to India crossing over Burma and then along the south side of the Himalayas, rather than the way the crow flies over Nepal and then into DEL/BOM. There are plenty of flights flying from China to KTM and KTM to India, so why the long routing?

Here's KE 655:
https://flightaware.com/live/flight/KAL655

And CA 889:
https://flightaware.com/live/flight/CCA ... /ZBAA/VABB
E pur si muove -Galileo
 
GalaxyFlyer
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Re: Why do KE/CA fly around Himalayas to India?

Tue Feb 27, 2018 4:25 am

Just a guess, either they an issue with overflight permits requiring certain entry/exit points for China or Nepal or the high terrain is a flight planning problem. Not uncommon for China to have routings off the GC due to military airspace, too.

GF
 
Tristarsteve
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Re: Why do KE/CA fly around Himalayas to India?

Tue Feb 27, 2018 7:38 am

They probably have a problem with the pax oxygen system. There is much of the area where you cannot descend immediately to 1000ft if required. Therefore you must have an enhanced oxygen system that works for longer than 20 minutes. Our B777 and B744 had the fwd cargo filled with oxygen bottles (behind the sidewall and in the roof) to enable direct flights over the himalayas (and Greenland). Perhaps these airlines find it easier to go round?
 
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Phosphorus
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Re: Why do KE/CA fly around Himalayas to India?

Tue Feb 27, 2018 10:37 am

I seem to remember that twins are not, legally, welcome, over Himalayan rooftop. So quads may, in principle, go over this area, and twins have to look for a way around.
Something to do with loss of engine scenarios, and ability to maintain altitude (if you fly at 10 000 m, and mountains beneath you are 8 800 m tall, suddenly you don't have that much of spare altitude, do you?)
Might be that plays a role, if those flights are on twins.
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BravoOne
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Re: Why do KE/CA fly around Himalayas to India?

Tue Feb 27, 2018 11:33 am

I would imagine that like others have stated, this is a pax oxygen issue combined with Minimum Sector Altitudes that surround the Hindu Kush regions. Most Jeppesen tailored high altitude enroute charts, will have "escape" routes printed them should you lose an engine and start a drift down. That combined with your oxygen supply will determine your course of action. Recall that the worst case scenario usually involves a combined engine loss along with a decompression, hence the decent to something lower than 10,000. If the MEA or MSA is above 10,000 you need O2 until you can get lower. As I recall you do not need O2 for every pax but rather a percentage value.

Boeing offer extended capacity O2 canister that last for 25 minutes as opposed to the 15 minute standard versions. Not positive about those numbers so don't call me on it. They also offer a gaseous O2 system with extended capacity on some models.
 
MaverickM11
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Re: Why do KE/CA fly around Himalayas to India?

Wed Feb 28, 2018 3:26 am

Tristarsteve wrote:
They probably have a problem with the pax oxygen system. There is much of the area where you cannot descend immediately to 1000ft if required. Therefore you must have an enhanced oxygen system that works for longer than 20 minutes. Our B777 and B744 had the fwd cargo filled with oxygen bottles (behind the sidewall and in the roof) to enable direct flights over the himalayas (and Greenland). Perhaps these airlines find it easier to go round?


BravoOne wrote:
I would imagine that like others have stated, this is a pax oxygen issue combined with Minimum Sector Altitudes that surround the Hindu Kush regions. Most Jeppesen tailored high altitude enroute charts, will have "escape" routes printed them should you lose an engine and start a drift down. That combined with your oxygen supply will determine your course of action. Recall that the worst case scenario usually involves a combined engine loss along with a decompression, hence the decent to something lower than 10,000. If the MEA or MSA is above 10,000 you need O2 until you can get lower. As I recall you do not need O2 for every pax but rather a percentage value.

Boeing offer extended capacity O2 canister that last for 25 minutes as opposed to the 15 minute standard versions. Not positive about those numbers so don't call me on it. They also offer a gaseous O2 system with extended capacity on some models.

Yeah I thought it might be O2 but I thought UA rolls supplemental O2 tanks onto its EWRBOM/DEL flights for that specific reason? Can you not do that on the 330 or a narrowbody? I also wondered that if you can fly China-KTM on narrowbodies all day, and KTM-India on narrowbodies, couldn't you route overhead above KTM?

http://www.gcmap.com/mapui?P=icn-mdl-bo ... xa-ktm-bom
E pur si muove -Galileo
 
FrmrKSEngr
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Re: Why do KE/CA fly around Himalayas to India?

Wed Feb 28, 2018 6:24 am

If you look at an Airway chart, they get pretty sparse over eastern China and Tibet compared to south of Nepal
 
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zeke
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Re: Why do KE/CA fly around Himalayas to India?

Wed Feb 28, 2018 7:02 am

Three reasons

1- China has limited airways that are permitted for international flights.

2- Eastbound flights are taking advantage of a 100+kts tailwind that is over Dakha and Kunming. Westbound flights are probably down around 30,000 ft this time of year to get out of some of the headwind. The jet stream stays on the southern side of the terrain.

3- the routes require depressurised and engine out performance assessments. Terrain on the route can be over 20,000 ft.
Last edited by zeke on Wed Feb 28, 2018 7:07 am, edited 1 time in total.
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BravoOne
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Re: Why do KE/CA fly around Himalayas to India?

Wed Feb 28, 2018 11:23 am

Just a side note;. The 787 is offered with three different capacity pax gaseous 02 systems so if an operator routinely operated on those kind of routes one would think they might opt for one of the larger capacity systems. Zeke's comments are certainly worthy of note as well.

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