Subject: Jumbo jet nosedive: Walkman to blame? +quot;It all started with a rumor that was

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Subject: Jumbo jet nosedive: Walkman to blame? "It all started with a rumor that was soon widely reported as fact: a DC-10, on final approach to New York's JFK airport, suddenly pitched violently to the left and nearly crashed. As the story goes, the loss of control was caused by a first-class passenger who had turned on his portable CD player." >From _Airlines and the Electronic Device Furor: Just Where's the Interference?_ by investigative journalist Peter S. Greenberg in the Sunday, April 4 edition of the San Jose (California) Mercury News, page 1T. He continues: "'That story is nothing but a rumor,' says Anthony Broderick, associate administrator for regulation and certification at the FAA [Federal Aviation Administration - C.H.]." "'We've checked every available source, and that event never happened,' he says. 'The picture painted in the mind's eye of the public is inaccurate. We've looked at electronic emissions for years, and the odds are so remote that something like this ever happened that we don't consider Walkmen, CD players or laptop computers a serious safety issue.'" "Specifically, Broderick explains that electronic flight controls are designed to be subjected to high levels of extraneous electronic emissions. 'In a worst-case scenario,' he says, 'there are failure modes built into these systems so that if there was a problem, the system would either shut down or there would be an alarm...in our tests we subject aircraft equipment to substantially more severe electronic interference than could ever be caused by passive individual devices.'" Greenberg's article also mentions a 1988 study conducted by the Radio Technical Commission for Aeronautics, which is described as a non- profit group that acts a a federal advisory committee. Greenberg says the group's study reported that there was was not sufficient evidence to prove that any of the following devices generated enough interference to disturb aircraft equipment: AM/FM/casette players, Dictaphones, hand-held video games, heart monitor units, portable computers, high-frequency marine band radios, and cellular phones. As a former private pilot, I have dealt with the FAA. In my experience, they have ALWAYS considered aircraft safety to be their top priority. And after millions and millions of airline operations upon which to base an opinion, and after specific testing for interference by consumer electronics equipment, the FAA appears to find no reason for concern. In my opinion, it does seem logical to wonder if a radio might interfere with navigation receivers. After all, radios contain local oscillators that can emit RF. In reality, though, the already tiny (and unmodulated) signal -- inside of a metal shield (the plane's fuselage) -- drops off to a truly miniscule level inversely proportional to the distance. Personal computers are probably the devices most likely to cause interference, as they can emit a relatively large amount of broadband RF (radio frequency noise). However, laptop computers have been used on airline flights for several years now, and, to my knowledge, there has been no evidence to suggest a problem. -Craig Haggart, KC6VHO Stanford Synchrotron Radiation Lab at SLAC Menlo Park, California [Crossposting to alt.folklore.science and .urban, and donning the asbestos suit.] From unknown Fri May 28 01:30:14 1993 From: lippard@skyblu.ccit.arizona.edu (James J. Lippard)

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