Re: EMI levels possible due to airborne military jammers?

From:         "peter (p.j.) ashwood-smith" <>
Organization: Bell-Northern Research Canada
Date:         28 Sep 95 03:52:47 
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>Does anyone have any knowledge of the EMI levels which could be
>encountered in flight, due to presence of airborne electronic
>countermeasures (jammers)?   Current engine FADEC's and aircraft avionics
>are Certified to withstand EMI levels of 200 volts/meter.  Is it possible,
>assuming normal minimum air traffic control separation distances, that a
>commercial aircraft could encounter EMI levels greater than the 200
>volts/meter, if some nearby military aircraft (Wild Weasel, EA-6B Prowler,
>EF-111, or whatever) happened to light off his jamming equipment, let's
>say as part of some exercise??   I'm trying to understand if this could
>theoretically be the source of some control system anomalies which don't
>seem to have any identifiable cause.

    While I don't know anything about the kind of EMI levels that can
be produced by electronic countermeasuers devices I do know something
about software and I would be more concerned about the software causing
these kinds of problems than just about anything else. Besides if you
were getting hit the memories would probably go nuts. You'd get parity
etc. errors pretty quickly. There is nothing like several millions lines
of real time code to create problems with no identifiable cause.


Peter Ashwood-Smith   	  |  email:
Bell Northern Research    |  work : (613)763-4534
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