As I said in earlier posting, ADF might be used to get a bearing to a known
transmitter, and thus line up an approach, but it is not IFR and cannot be
used as the sole source of information in order to make a safe landing.  My
experience is with transport, not general aviation class aircraft.  On
transports, the ADF loop is too far away from any passenger-carried
equipment to cause a problem.

In principle, it would be easy to bank an aircraft via rfi.  All that is
needed is that the aircraft be on auto-pilot and the auto-pilot is
responding to ground-based navigation transmissions for position
information.  That is what happened to that storied DC-10.

----------
>From: Cortland Richmond <cortland.richm...@alcatel.com>
>To: Ken Javor <ken.ja...@emccompliance.com>
>Cc: Mike Hopkins <mhopk...@thermokeytek.com>, cherryclo...@aol.com,
emc-p...@majordomo.ieee.org
>Subject: Re: EMC-related safety issues
>Date: Thu, Jan 3, 2002, 11:40 AM
>

> I'm old enough, Ken, to remember ADF approaches! But
> laptop switchers often operate inband to frequencies
> used by aviation non-directional beacons. This makes
> them more of a threat than the harmonics from
> lower-frequency ones. It is also, of course,
> possible for the laptop's other emissions to
> interfere with an ILS or VOR receiver.
>
> Some of the complaints I've seen have not been
> rationally explicable, however. For example, at one
> of my former employer's (no longer in existence) a
> report was received that a laptop caused an aircraft
> to bank two degrees. I've worked with aircraft
> stabilization systems, and I've yet to figure out a
> mechanism how that could happen.
>
> Cortland
> (What I write here is mine alone.
> My employer does not
> Concur, agree or else endorse
> These words, their tone, or thought.)
>
> Ken Javor wrote:
>
>> In my experience it is EXTREMELY unlikely that
>> personal electronics could have disturbed ADF
>> heading indication.  The ADF sensor is an
>> electrostatically shielded loop which is mounted
>> typically on the belly of a transport class
>> aircraft, well away from any passenger-conveyed
>> intense sources of magnetic fields.  The loop is
>> very insensitive and requires quite a bit of
>> magnetic field to respond and is completely
>> insensitive to electric fields altogether.
>> Further, no one would use ADF to line up an
>> approach on a runway.
>>
>>
> 

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