Re: differents in DC10-30 and -40

Date:         03 Aug 97 02:50:18 
From:         "Mark E. Ingram" <markt@mickey.mo-net.com>
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On 31 Jul 1997, Karl Swartz wrote:

> >     I then started asking around and finally dug up a DC-10-30 flight
> >manual. It turns out that the flight engineer can isolate the centre
> >gear (i.e. keep it retracted).

> >The benefit is an increase in climb-limited landing weight

Another *potential* benefit - seldom realized - is to keep the center gear
retracted during a landing at an airport that bases its landing fees on
the number of wheels (or gear).  Narita comes to mind as one such airport
that might have operated this way (at least in the late Eighties).

> Can it be deployed once on the ground?

Yes, but I seem to recall that the aircraft would have to be jacked up
slightly to accomplish the extension.

> I wouldn't have thought so, but that means a light landing would then
> force a light takeoff.

Exactly so, and such a light takeoff would usually wipe out any landing
fee savings.  When I used to fly into Auckland, NZ, we were told by our
airline management that when the aircraft was going only as far as Sydney
on its next flight (about three hours away), we had the option of saving
on the landing fees at AKL by landing with the center gear retracted.  In
dozens of flights, however, I never saw anybody actually do it.

Mark E. Ingram

MarkT@Mo-Net.Com (also mingram@mail.orion.org)