Re: Static from Cross-feed

Date:         13 Jan 97 18:35:32 
From:         faurecm@halcyon.com (C. Marin Faure)
Organization: Northwest Nexus Inc.
References:   1 2 3
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In article <airliners.1997.127@ohare.Chicago.COM>,
nospam.jfmezei@videotron.ca wrote:

> Bilal Yousuf wrote:
> > B) The B747 can be ground conditioned, but if ground AC is not available the
> > APU is used to drive the aircraft airconditioning system, which does create
> > a lot of heat in the area fwd and under the wing.
>
> When a plane is at a gate, I assume those yellow/orange flexible pipes
> are the ones used to supply air to the plane. But I would also assume
> that electrical power is also supplied from the ground so that the
> aircraft need not rely on its APU. Is this a correct assumption ?

Not always. Actually, very few airports make it a practice to supply
airplanes at the gate with power and air during a normal turnaround.  Most
airplanes continue to run their APUs.  One airport that has vigorously
adapted a program of supplying ground power and air is Zurich.  I filmed
there a couple of years ago for a Boeing/Airbus produced video on aviation
and the environment.  Zurich guarantees a hookup of ground power within 30
seconds of gate arrival and heated or cooled cabin air within two or three
minutes of engine shutdown.  The flip side of this is that any airline
caught running an APU at the gates is fined.  For this reason, the
Russion-built Aeroflot jets that use Zurich have to park out on the ramp
and they are fined at every visit as they cannot use the ground power and
air supplied by the terminal.

The purpose of this regulation is to reduce noise and pollution.  I
believe the same procedures are in effect at Amsterdam, and possibly other
airports as well.  But most airplanes at the gates at US airports during a
normal short turnaround are running their APUs.

C. Marin Faure
  author, Flying A Floatplane