more on 2 comments on cell phones in the air]

[David Farber <dave () farber net>]

-------- Original Message --------
Subject: Re: [IP] more on 2 comments on cell phones in the air
Date: Mon, 06 Mar 2006 15:40:51 -0800
From: Sid Karin <skarin () ucsd edu>
To: dave () farber net
References: <012101c640f9$7fb2daa0$6601a8c0 () digisle com>
<ADB14630-F7F2-43D6-84EB-94217EB752AA () farber net>

Dave,

This is well put.  Also note that general aviation aircraft
often use laptops to present moving map information from
a GPS, and more recently satellite broadcast weather and
IFR charts.  In the cockpit.  Right near the GPS, VHF and LF
receivers and all the other electronic equipment.
It doesn't seem to cause any problems.

Note also that one of Burt Rutan's unique aircraft of a few years
ago actually used a Mac Powerbook, mounted in the aircraft,
as the instrument panel itself.

General aviation headsets and intercom units are often wired
for portable and/or mounted (in the instrument panel) CD players/iPods/etc.
I have never heard of any of these causing a problem, nor
have I ever seen them cause a problem.  I can report that they
are very pleasant to use.   There is usually an automatic
mute function that is triggered by use of the communication systems.

I have seen people using a cell phone in a general aviation aircraft
cockpit and I have not observed any interference during the call.

Note the the original agency that banned cell phones
on aircraft was the FCC,  fearing that the footprint of a
cell phone at 30,000 feet included far too many cells for
the system to deal with.  The FAA didn't join the act for
several years.    A friend who is a captain for a major carrier
speculated that it all devolves from a crew who busted minima
on an approach and decided to blame the passengers.

Finally,  one might wonder why, if interference is a problem,
its ok to use portable electronics above 10,000 feet?
Has someone determined that that is sufficient altitude
to recover from an unusual attitude induced by Mick
Jagger or Grand Theft Auto?



        Cheers,

                .......Sid




> Begin forwarded message:
>
> From: "Andrew D. Swart" <andrew () swart com>
> Date: March 6, 2006 3:39:25 AM EST
> To: btm () templetons com, glenn () glennf com
> Cc: dave () farber net, ip () v2 listbox com
> Subject: RE: [IP] 2 comments on cell phones in the air
> Reply-To: andrew () swart com
>
> > ...Commercial jet GPSs use, I believe, and external antenna
> > outside the metal body of the aircraft in any event.
>
> For various reasons, including the growing popularity of using portable
> GPS devices, GPS antennas in smaller general aviation (GA) aircraft are
> often found inside the plane, but under the slanted front windshield.
> Very different from an external antenna that is presumably well-shielded
> from passengers and their toys.  The paper's reference to a single
> instance of GPS interference in a GA aircraft doesn't seem all that
> useful without additional information.  Not only am I curious about
> antenna proximity to the cell phone, but it would be useful to know
> whether the GPS unit was "fooled" into calculating a false location, or
> reported the loss of signal integrity (GPS receivers certified for
> instrument approaches have signal integrity monitoring).
>
> As a pilot, I would find research more useful if it directly looked for
> adverse effects on common aircraft navigation equipment from
> non-aviation, onboard transmitters (whether in the cabin or in cargo
> areas).  Perhaps it would lead to revised standards for navigation
> equipment installations, and fewer concerns that an innocently
> overlooked device could harm us.
>
> Andrew Swart
>
>
>
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-- 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
     Sidney Karin, Ph.D., P.E.       858-534-5075 (voice)
                                        858-822-5443 (fax)

        skarin () ucsd edu
     Professor,
     Department of Computer Science and Engineering
     Director Emeritus
     San Diego Supercomputer Center
     University of California, San Diego
     9500 Gilman Drive
     La Jolla,  CA  92093-0505



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