Re: 4-point Landing Gear Aircraft

Date:         22 Jul 99 23:30:35 
From:         saccani@omen.net.au (Paul Saccani)
Organization: Omen Internet in Perth, Western Australia
References:   1
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On 10 Jul 99 02:33:31 , "James Fu" <jamesfu@ibm.net> wrote:
>Why is it that pilots of aircraft with 4-point landing gear systems (nose,
>center, and one each main) sometimes deploy only the nose and main points,
>and not the center?  Naturally, aircraft like the MD11, DC10, and A340 are
>the referenced aircraft here.

Weight.  Usually, all gear is down for take off, unless TOW is low.
By the time the destination is reached, fuel burn means the landing
weight is less, and so the extra gear is not required.  Only the long
range DC-10 had the extra gear, BTW.  It is not uncommon for MTOW to
exceed MLW, BTW.  Why bother having the extra MTOW gear and then
stowing it for landing?  Reduces wear and tear etc...  So it is usual
for the extra gear not to be used for landing, and a decision on it's
use for take off is done on the basis of the TOW.  This will often be
specified on the printout the crew recieve with the company flight
plan.