Sponsor Message:
Civil Aviation Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
High Altitude For Short-haul Flights  
User currently onlineUAEflyer From United Arab Emirates, joined Nov 2006, 1037 posts, RR: 0
Posted (4 years 7 months 1 week 6 days 6 hours ago) and read 13248 times:

Why some flights go up to 36000 feet on a short-haul trip, like for instance a flight from KWI to DXB , the aircraft reachs over 30k height, while flights from Asia to Europe which is 10 times more in time and distance rarely reach 36,000 feet.
Could some of our experts explain the relation between distance, height, and speed.

21 replies: All unread, jump to last
 
User currently offlineDAL763ER From United Kingdom, joined Oct 2008, 522 posts, RR: 0
Reply 1, posted (4 years 7 months 1 week 6 days 5 hours ago) and read 13183 times:
Support Airliners.net - become a First Class Member!

It's very efficient to climb as high as possible on short flights as thus, you would keep the engines on idle for descent. The T/D(top of descent) would overlap, or would be very close to the T/C(top of climb) and the fuel consumption would be minimum.

If one were to climb to, say 24000 feet on a 250 mile flight, one would also use up fuel for cruising, whereas in the first case, one would not.



Where aviation is not the side show, it's the main show!!!
User currently offlineRFields5421 From United States of America, joined Jul 2007, 7607 posts, RR: 32
Reply 2, posted (4 years 7 months 1 week 6 days 5 hours ago) and read 13070 times:

A lot of the decision as to cruise altitude has to do with the aircraft weight and the weather.

A long haul aircraft for lengthy flight may have extra fuel and cargo (pax and real cargo) weight which will limit the altitude until a substantial percentage of the fuel is burned off. A flight such as you mentioned of less than 500nm would not have weight issues limiting the highest altitude.

Winds are also a significant factor in flight planning. This is especially important in long distance flights such as the six time longer flight DXB-LHR.

When over continental areas - there are altitude restrictions based on the aircraft direction of flight. RVSM in the US has east bound flights flying at odd altitudes - FL310, FL330, FL350, FL370 etc - and west bound flights at even altitudes - FL320, FL340, FL360, etc.


User currently offlineDocLightning From United States of America, joined Nov 2005, 19415 posts, RR: 58
Reply 3, posted (4 years 7 months 1 week 6 days 4 hours ago) and read 13035 times:

I was once rather startled to learn that my SFO-SAN flight had gone to FL 380. It was explained to me by the pilot after the flight that "the most efficient flight path is a parabola." He said basically what DAL763ER said, that the savings from being able to glide all the way down from that altitude more than made up for the fuel burned in getting up to that altitude as opposed to stopping at, say FL 280 and cruising there.

We climbed to 380, stayed there for about 3 minutes, and then began our descent.


User currently offlineBrouAviation From Netherlands, joined Jun 2009, 985 posts, RR: 1
Reply 4, posted (4 years 7 months 1 week 6 days 4 hours ago) and read 12913 times:



Quoting UAEflyer (Thread starter):
while flights from Asia to Europe which is 10 times more in time and distance rarely reach 36,000 feet.

Where do you get that knowledge from? Last month I flew ZRH-DXB and DXB-CPH, and both flights got well above 36000 feet.

Quoting DAL763ER (Reply 1):
If one were to climb to, say 24000 feet on a 250 mile flight, one would also use up fuel for cruising, whereas in the first case, one would not.

Still, the FRA-AMS route I regularly fly, never climbs above FL220/240, when the distance is more then enough to reach at least 30,000.

Quoting DocLightning (Reply 3):
the most efficient flight path is a parabola.

I know, still I find it very difficult to understand that the energy used to move along the Y-axis of a flight path, is compensated by the energy saved when gliding down, and the lower temperature.

And lets not forget the weather circumstances, which play a major role in this matter. The height when the tropopauze starts, the jetstream, et cetera all are important factors to be taken into consideration when selecting a cruising altitude.



Never ask somebody if he's a pilot. If he is, he will let you know soon enough!
User currently offlineFlyboy1108 From United States of America, joined Jan 2007, 94 posts, RR: 0
Reply 5, posted (4 years 7 months 1 week 5 days 20 hours ago) and read 12523 times:

Flying PHL-PIT on a US 757 in 2005 I remember the pilot say we reached our cruising altitude of FL360. On the way home in a 734, we cruised at FL220. The flight is about 270 miles. I'm assuming that had to do with the headwind component (strong headwind on the way out, strong tailwind on the way back). At any rate, we cruised at FL360 literally for 90 seconds (the pilot told us this over the PA) and begand our descent into PIT. I found it really interesting how high we went on the way out, compared to how not high we were on the way home.

NCB
ABE



"God is great, beer is good, and people are crazy"
User currently offlineFauzi From Brunei, joined Jul 2005, 219 posts, RR: 0
Reply 6, posted (4 years 7 months 1 week 5 days 17 hours ago) and read 12416 times:

I remember that the short 30mins flight BWN - BKI stayed just above the first level of clouds. Seatbelt signs were constantly on, so no toilets on that flight!


BI - The Asian Underdog
User currently offlineDAL763ER From United Kingdom, joined Oct 2008, 522 posts, RR: 0
Reply 7, posted (4 years 7 months 1 week 5 days 17 hours ago) and read 12375 times:
Support Airliners.net - become a First Class Member!



Quoting BrouAviation (Reply 4):
Still, the FRA-AMS route I regularly fly, never climbs above FL220/240, when the distance is more then enough to reach at least 30,000.

Well, I assume it's because of the area you're flying in. FRA and AMS are both huge airports with lots of traffic, so I don't think there's a way that ATCOs could make room for a short flight between many other flights inbound and outbound of AMS and FRA.



Where aviation is not the side show, it's the main show!!!
User currently offlineAirbuster From Netherlands, joined Mar 2007, 441 posts, RR: 0
Reply 8, posted (4 years 7 months 1 week 5 days 15 hours ago) and read 12274 times:

We have done AMS-HAM at FL350 in the past, it was just about doable, once you levelled off you got your descent clearance again.

The most efficient flight path is a parabolic one, but it is all weight, weather, route, airspace permitting.

We climb up to FL350 in about 20 min, so every route of 35+min should be doable.

rgds

AB



FLY FOKKER JET LINE!
User currently offlineDALCE From Netherlands, joined Feb 2007, 1677 posts, RR: 7
Reply 9, posted (4 years 7 months 1 week 5 days 15 hours ago) and read 12234 times:

I once had a jumpseat on the OSL-AMS (597nm) stretch with SK, and we cruised at FL400 for at least like 15minutes or so. I never thought the 737 would actually climb that high on such a short flight.


flown on : F50,F70,CR1,CR2,CR9,E75,143,AR8,AR1,733,735,736,73G,738,753,744,319,320,321,333,AB6.
User currently offlineDAL763ER From United Kingdom, joined Oct 2008, 522 posts, RR: 0
Reply 10, posted (4 years 7 months 1 week 5 days 14 hours ago) and read 11940 times:
Support Airliners.net - become a First Class Member!

Malev climbs to FL390-410 on BUD-OTP runs which are about 350nm.


Where aviation is not the side show, it's the main show!!!
User currently offlineAirbuster From Netherlands, joined Mar 2007, 441 posts, RR: 0
Reply 11, posted (4 years 7 months 1 week 5 days 13 hours ago) and read 11636 times:



Quoting DALCE (Reply 9):

Oslo-Amsterdam is at least an hours flight, and most of the time somewhat longer, everything over 45 min flight time can justify climbing up to max cruise if efficient.

The 737-600 is a fast climber i believe so it doesn't surprise me at all. We always cruise at max level (FL340 southbound) with our Fokker 70 on all the Norwegian-Amsterdam routes, also the Kristiansand-AMS wich is about a 100nm shorter than the OSL-AMS.

just my 2cents

rgds

AB



FLY FOKKER JET LINE!
User currently offlineStealth777 From United States of America, joined Feb 2006, 372 posts, RR: 0
Reply 12, posted (4 years 7 months 1 week 5 days 13 hours ago) and read 11427 times:

At the company I work for we use a 10% rule for altitude vs distance, plus a couple of thousand feet to calculate the cruise level we will file a plan at. For example if the flight plan distance was 368 miles we will file the cruise altitude between 360-400. Sometimes we may file it at a lower altitude for different reasons. One would be to avoid the high shears (which would equate to light to moderate chops), restrictions by atc or Euro-control (prime example from earlier was the FRA-AMS route) or pilots request.

For the 2nd part in the op's question about the long flights not getting up as high, there are a couple of factors playing into that. Primarily though its the weight of the aircraft at departure. If the aircraft is heavy it will have to do step climbs until it reaches its peak performance flight level. Unless you are in a G-5 or a Global and you are doing a long flight (excess of 6-7 hrs) you will starting off in the mid 30's and step climbing your way to the ideal flight level.

Hops this clears things up a bit more. The parabolic flight plans might be ideal for the commercial jets but with the corporate jets (that's who we mostly deal with) they achieve their speeds in cruise flight regardless of the altitude (of course the fuel burn will be higher in lower altitudes) but the fast speeds that the pax want to travel in happens at cruise.

-Stealth


User currently offlineMqtmxguy From United States of America, joined Nov 2007, 196 posts, RR: 0
Reply 13, posted (4 years 7 months 1 week 5 days 12 hours ago) and read 11130 times:



Quoting BrouAviation (Reply 4):
I know, still I find it very difficult to understand that the energy used to move along the Y-axis of a flight path, is compensated by the energy saved when gliding down, and the lower temperature.

Because jets are horribly inefficient at lower altitudes. (lower speeds and higher fuel burn due to air density). Therefore getting up high where you get the most efficiency and then letting gravity do the work of bringing you back down is a far faster more fuel efficient vs. trudging low and slow through the thicker, lower air.



Well at least we can all take comfort in the fact that NW will never retire their DC-9s
User currently offlineN6168E From United States of America, joined Sep 2007, 48 posts, RR: 0
Reply 14, posted (4 years 7 months 1 week 5 days 6 hours ago) and read 8466 times:

Years ago, I remember flying EI SNN-DUB (106 NM) in a 747 at 4000ft and then returning a week later in a 707 at FL180.... It was real cool flying over the Irish landscape at such a low altitude.

User currently offlineAirbuseric From Netherlands, joined Jan 2005, 4253 posts, RR: 51
Reply 15, posted (4 years 7 months 1 week 5 days 2 hours ago) and read 8298 times:



Quoting BrouAviation (Reply 4):
Quoting UAEflyer (Thread starter):
while flights from Asia to Europe which is 10 times more in time and distance rarely reach 36,000 feet.

Where do you get that knowledge from? Last month I flew ZRH-DXB and DXB-CPH, and both flights got well above 36000 feet.

Because the weight of the widebodies, the route congestion (not too many routes over Siberia are open for these fligths) and the restricted flightlevels. Most Euro-Japan/Korea bound flights will cross Russian airspace at FL360, until east Siberia were they can climb to FL370/390/410/430, also because they are at lighter weight then.

Quoting BrouAviation (Reply 4):
Still, the FRA-AMS route I regularly fly, never climbs above FL220/240, when the distance is more then enough to reach at least 30,000.

Because max flightlevel on this route is FL245 and AMS-FRA gets odd flightlevel (max FL230) and FRA-AMS is max FL240. This is flightplanning.
Said that, crew can always request higher altitudes with Eurocontrol, but if it's not planned like that, it's not always granted.



"The whole world steps aside for the man who knows where he is going"
User currently offlineNZ107 From New Zealand, joined Jul 2005, 6407 posts, RR: 38
Reply 16, posted (4 years 7 months 1 week 5 days 2 hours ago) and read 8278 times:

I once travelled at FL410 between AKL-WLG on a 733. It's 259nm which isn't very long at all. The usual for New Zealand domestic jets is somewhere between FL330 and 380 from my experience.


It's all about the destination AND the journey.
User currently offlineJBAirwaysFan From United States of America, joined May 2009, 951 posts, RR: 0
Reply 17, posted (4 years 7 months 1 week 5 days 2 hours ago) and read 8231 times:

DAB-ATL is roughly a 55 minute flight and is about 367 miles. We normally top out at FL330. We cruise for about ten or fifteen minutes and then we begin our descent. I have always wondered this as well. Interesting answer.


In Loving Memory of Casey Edward Falconer; May 16, 1992-May 9, 2012
User currently offlineCpd From Australia, joined Jun 2008, 4879 posts, RR: 38
Reply 18, posted (4 years 7 months 1 week 4 days 23 hours ago) and read 8127 times:

And some B747-400ER runs from SYD-MEL and back reach FL400 very quickly, with reduced power. To give you an idea of the rate of climb, imagine RWY16R at SYD, then think of where the observation deck is. B747-400ER lifts off just past the observation deck.

Also been on a B737-800 at FL380. Climbed very quickly to that altitude and stopped there for a short while and descended not long after. B767-300 is also good for those short flights - particularly well powered and fast climbing.


User currently offlineSeaBosDca From United States of America, joined Sep 2007, 5316 posts, RR: 4
Reply 19, posted (4 years 7 months 1 week 4 days 22 hours ago) and read 8085 times:

Quoting Airbuster (Reply 11):
The 737-600 is a fast climber i believe so it doesn't surprise me at all.

Here in the U.S., Southwest has an enormous fleet of 737-700s which it uses for many short hops all over the country. The 737-700 is a rocket, and if you look at SWA flights you will often see even the short flights way up at FL400 and FL410.

Quoting NZ107 (Reply 16):
I once travelled at FL410 between AKL-WLG on a 733.

This is very unlikely given that the 733 is only certified to FL370.

[Edited 2009-12-20 18:56:47]

User currently offline71Zulu From United States of America, joined Aug 2006, 3061 posts, RR: 0
Reply 20, posted (4 years 7 months 1 week 4 days 22 hours ago) and read 8006 times:

WN regularly climbs to 30,000 feet between HOU and DAL, a distance of only 208 nm.

Check out this track log,

http://flightaware.com/live/flight/S...4/history/20091221/0206Z/KHOU/KDAL

http://flightaware.com/live/flight/S.../20091221/0206Z/KHOU/KDAL/tracklog

Climbs to FL300 and then almost immediately starts the descent.

You figure they have done enough trips between HOU and DAL to know the best way to operate it.



The good old days: Delta L-1011s at MSY
User currently offlineNZ107 From New Zealand, joined Jul 2005, 6407 posts, RR: 38
Reply 21, posted (4 years 7 months 1 week 4 days 22 hours ago) and read 7998 times:



Quoting SeaBosDca (Reply 19):
This is very unlikely given that the 733 is only certified to FL370.

Hmm, right I must be mistaken there.


I flew SYD-MEL at FL390 a couple of times on a 73H and A332 and also CHC-AKL at FL390 in a 73H.



It's all about the destination AND the journey.
Top Of Page
Forum Index

This topic is archived and can not be replied to any more.

Printer friendly format

Similar topics:More similar topics...
Overseas Delivery For Short Haul Aircraft: How? posted Sat Aug 5 2006 12:45:00 by Adric10
Turbulence On Short Haul Flights posted Tue Jul 11 2006 15:40:27 by LY777
My Personal Airshow On Short Haul Flights! Yayers! posted Tue Apr 18 2006 20:58:22 by RootsAir
SIA Short-haul Flights A/c posted Fri Feb 17 2006 17:14:24 by Timboflier215
Best Design For A Short-haul Airliner posted Sun May 15 2005 05:55:06 by Dandy_don
AA's Super High Price For A Short Trip. posted Tue Feb 8 2005 02:48:01 by ReguPilot
Online Seat Bookings For Short Haul.. posted Fri Apr 23 2004 11:20:01 by Richardw
Gulf Air To Acquire Jets For Short-haul Routes posted Sun Nov 9 2003 18:25:08 by GF-A330
EK Balancing Options For Short-haul. posted Sun Jan 23 2000 14:55:24 by Tailscraper
No More Funding For Scottish Long Haul Flights posted Sun Sep 10 2006 21:42:58 by Humberside