From: email@example.com (Dennis Chamberlin) Organization: Tektronix, Inc., Beaverton, OR. Date: 17 Jan 93 17:57:57 PST References: 1 2 3 Followups: 1 2
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In article <airliners.1993.49@ohare.Chicago.COM> firstname.lastname@example.org (Kevin Driscoll) writes: >In article <airliners.1993.36@ohare.Chicago.COM> email@example.com.EDU (Keith Barr) writes: >> >>Wouldn't there be a change in attitude if the autopilot was engaged, >>which it obviously was, and if the navigation equipment was disturbed by RF? > >In this case, it is >possible (but highly improbable) that a CD player could effect the radio >nav (which is forward and under the cockpit). I guess I can't swallow the idea that a passenger's CD player is going to find its way into nav or other avionics gear. If the manufacturer really said this, I interpret it as straw-grasping in the absence of other explanations. The most powerful components of a CD player are presumably the motor drive and audio output. Not much there. I would think that if the aircraft systems were so exquisitely sensitive and even if by some fault the system wiring in the cabin area were effectively unshielded, the resulting problems would be frequent to continuous, and emerge from many other sources than CD players. We all live in an environment of electrical noise from multitudes of man-made and even natural sources. Some of these are of much greater magnitude than anything that could be supplied by the batteries in the CD player. The normal operations of the aircraft itself emit electromagnetic energy of considerable power. The cabin audio/video system is itself of much higher power than the CD player, although the manufacturer does control its installation and engineering. I am sure that during development and manufacture, an expensive set of quite sensitive measurements establish the electromagnetic compatibility (EMC) of the aircraft with itself and both known and arbitrary outside sources. I believe that if the various and powerful internal and external sources over a broad band were ever to start talking to the sensitive systems, we are going to have much more to worry about than CD players.