Re: B737-400 range

Date:         08 Jan 2000 13:39:03 
From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
References:   1 2 3
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>Also, the fact that the Boeing homepage for the 737-400 lists two different
>versions but only one range which seems strange. It says:

>"The basic airplane gross weight is 138,500 pounds (62,820 kg), with an
>optional high-gross-weight version of 150,000 pounds (68,040 kg). Fuel
>capacity is 5,311 gallons (20,105 L), expanding to 6,295 gallons (23,825 L)
>with two optional tanks."

>How can both have a range of 2050 nm "with 148 passengers" when one version
>has 20% gallons more fuel? Seems weird.

It's not really that weird.  Obviously the HGW version will have the
greatest range.  The extra weight is only useful for range, since the
maximum landing weight (MLW) only goes up by 3,000 lbs, and that's
probably the same as the increase in the empty weight of the plane.
Effectively, then, you're asking them to tell you it has less range
if you don't put as much fuel aboard.

Boeing (and any other manufacturer) typically offers a variety of
options which can affect range.  For the 737-400, there're aren't just
two MGTOW options but a range of them, priced accordingly.  Likewise,
while you'll get CFM56 engines, you have a choice of the exact model
and the thrust rating.  Looking at the 737-500, the MGTOW range runs
from 115,500 lbs to 133,500 lbs.  Southwest chose a relatively low
120,000 lbs for their planes, because they use them on relatively short
routes and didn't need the range.  They might have chosen higher-thrust
engines, though, because they have a lot of hot-and-high flying out of
PHX and LAS and would therefore want the takeoff performance.  It's not
feasible or reasonable for Boeing to list the range of every incremental
option, though if you're thinking of buying a 737 I'll bet they'll work
with you to determine the range in your environment.

--
Karl Swartz	|Home	kls@chicago.com		http://www.chicago.com/~kls/
		|Work	kls@netapp.com		http://www.netapp.com/
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