Because I flew home yesterday... Please excuse some bad language in the video. If you used a portable phone in the 1960s, it operated in the VHF bands, it used a lot of power, and some of that power caused it to radiate in undesired frequencies. (Google: tempest compromising emissions.) These tempest emissions interfered with the Loran radio navigation receivers in common use in that decade. After an airplane crash was blamed on this the FAA made a commandment: Thou Shalt Not Use Portable Phones On Airplanes. Decades later, if you brought your portable TV or Osborne 1 computer onto an airplane, it had its own tempest emissions from the battery-powered CRT tube that likewise could possibly confuse radio navigation gear. The FAA being a bureaucracy never got around to revising their commandment. And the airlines and passengers became accustomed to being pushed around like this. Nowadays, a Kindle uses e-ink technology that sips tiny amounts of electricity. Theres not enough energy available for tempest emissions to goof up airplane navigation systems. A cell phone or ipad in airplane mode uses a bit more electricity to run its display, but this, too isnt much. Thus, the stewardesss assertion that magic requires you turn off your electronic devices is as plausible as any explanation youll hear. The real reason why you must turn off your electronic devices during take-off and landing is BECAUSE THEY SAY SO, nothing more. And if you question them they can put you off the plane.
Posted on: Fri, 23 May 2014 17:03:54 +0000
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