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WN Climb Rate  
User currently offlinedcaord From United States of America, joined Nov 2010, 37 posts, RR: 0
Posted (1 year 4 months 1 week 5 hours ago) and read 2774 times:

I've noticed, consistently over many years, WN flights seems to take of and climb at a significantly steeper rate than other airlines. I would have never thought that this is something that could vary airline to airline, but rather might be based off airport or aircraft. That being said, I have noticed now on dozens of WN flights out of a wide range of airports, it seems to be consistent that W9 737s climb faster and steeper than others. Is this accurate? If so, whats the reasoning?

[Edited 2013-06-25 18:09:16]

[Edited 2013-06-25 18:09:34]

12 replies: All unread, jump to last
 
User currently offlineB747400ERF From United Kingdom, joined Jun 2013, 494 posts, RR: 1
Reply 1, posted (1 year 4 months 1 week 5 hours ago) and read 2767 times:

I do not know who W9 is either, but my guess is they might not use a derated climb while other airlines you fly, do?

User currently offlinedcaord From United States of America, joined Nov 2010, 37 posts, RR: 0
Reply 2, posted (1 year 4 months 1 week 5 hours ago) and read 2767 times:

Apologies....WN

Filler

Filler

Filler


User currently offlineflymia From United States of America, joined Jun 2001, 7215 posts, RR: 10
Reply 3, posted (1 year 4 months 1 week 5 hours ago) and read 2767 times:

W9 as in Air Bagan??

I am guessing maybe WN is what you meant to type?

Maybe what ever airline you are referring to uses a higher than usual cost index when programing the FMC.
If it is WN it could also be that they do more shorter haul flights than most airlines which means a lot less fuel for flights. Less fuel, less weight, higher rate of climb.



"It was just four of us on the flight deck, trying to do our job" (Captain Al Haynes)
User currently offlineB747400ERF From United Kingdom, joined Jun 2013, 494 posts, RR: 1
Reply 4, posted (1 year 4 months 1 week 4 hours ago) and read 2742 times:

Well for WN, I don't believe they carry the amount of cargo that other airlines carry. So their gross weight is going to be lower than a similar 737 from United or American. They probably use a higher cost index and no derated climb mode also.

User currently offlineStarlionblue From Greenland, joined Feb 2004, 17078 posts, RR: 66
Reply 5, posted (1 year 4 months 1 week 4 hours ago) and read 2725 times:

Quoting B747400ERF (Reply 5):

Well for WN, I don't believe they carry the amount of cargo that other airlines carry. So their gross weight is going to be lower than a similar 737 from United or American. They probably use a higher cost index and no derated climb mode also.

Cargo being less I can understand. Lower weight means higher climb rate. The faster you can get to altitude in a jet, the lower your total fuel burn.

However not using derate when possible is not very rational. The maintenance savings are rather large despite the higher fuel costs.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineGoldenshield From United States of America, joined Jan 2001, 6085 posts, RR: 14
Reply 6, posted (1 year 4 months 1 week 4 hours ago) and read 2701 times:

Quoting B747400ERF (Reply 5):

Well for WN, I don't believe they carry the amount of cargo that other airlines carry.

Actually, you'd be surprised at just how much cargo they DO carry.



Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3166 posts, RR: 7
Reply 7, posted (1 year 4 months 1 week 3 hours ago) and read 2665 times:

Quoting B747400ERF (Reply 2):
but my guess is they might not use a derated climb while other airlines you fly, do?

Actually from what I understand WN has "power by the hour" maintenance agreements in which they always use derated climb and takeoff thrust. Not sure about the 737, but the climb derate washes out between 10,000 and 12,000 feet on many Boeing airplanes (10-30K as an option).

Quoting Starlionblue (Reply 6):
However not using derate when possible is not very rational. The maintenance savings are rather large despite the higher fuel costs.

Yep, I know that's counter-intuitive, but a derated climb actually uses a bit more fuel than un-derated climb.


User currently onlineLH707330 From United States of America, joined Jun 2012, 812 posts, RR: 0
Reply 8, posted (1 year 4 months 6 days 22 hours ago) and read 2560 times:

Quoting BoeingGuy (Reply 8):
Yep, I know that's counter-intuitive, but a derated climb actually uses a bit more fuel than un-derated climb.

How is it counter-intuitive? Most engines get better SFC under load and burn less high up, it's the same concept as accelerating to get through a yellow light instead of waiting for the next phase at idle.

Edit: Are you suggesting that it's counter-intuitive because the instantaneous burn is higher?

[Edited 2013-06-25 23:53:50]

User currently offlineStarlionblue From Greenland, joined Feb 2004, 17078 posts, RR: 66
Reply 9, posted (1 year 4 months 6 days 13 hours ago) and read 2456 times:

Quoting LH707330 (Reply 9):
Quoting BoeingGuy (Reply 8):
Yep, I know that's counter-intuitive, but a derated climb actually uses a bit more fuel than un-derated climb.

How is it counter-intuitive? Most engines get better SFC under load and burn less high up, it's the same concept as accelerating to get through a yellow light instead of waiting for the next phase at idle.

Edit: Are you suggesting that it's counter-intuitive because the instantaneous burn is higher?

It's perfectly clear if you've studied jet engines, but if you are a layman it can "make more sense" that climbing slower uses less fuel.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3166 posts, RR: 7
Reply 10, posted (1 year 4 months 6 days 11 hours ago) and read 2401 times:

Quoting LH707330 (Reply 9):
Edit: Are you suggesting that it's counter-intuitive because the instantaneous burn is higher?
Quoting Starlionblue (Reply 10):
It's perfectly clear if you've studied jet engines, but if you are a layman it can "make more sense" that climbing slower uses less fuel.

Correct. Even a layman can deduce that climbing at a lower thrust setting burns less fuel instantaneously. It takes an expert like one of us to realize that getting to a more efficient cruise altitude faster ultimately burns less fuel and makes an underated climb burn less fuel in total.


User currently offlinesancho99504 From United States of America, joined Dec 2005, 570 posts, RR: 0
Reply 11, posted (1 year 4 months 2 days 7 hours ago) and read 2016 times:

WN has places to go and they don't have time to lolly gag around. Time is money. Ever watch them taxi around?


kill 'em all and let God sort 'em out-USMC
User currently offlineseabosdca From United States of America, joined Sep 2007, 5647 posts, RR: 6
Reply 12, posted (1 year 4 months 2 days 7 hours ago) and read 2012 times:

They (mostly) fly aircraft with better thrust-to-weight ratios than other operators.

Their 73Gs are hot rods, and their 733s also do better than much of the heavier competition, especially at lower altitudes.

Everyone else is using 738s/739s and A320s/A321s that don't have quite the same shove in the back.


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