[ltp] Re: Linux-Thinkpad digest, Vol 1 #632 - 27 msgs

[James Knott]

morpheus wrote:
> A few years ago British Airways lent an airplane to the British CAA, who
> placed multiple transmitters (to simulate electronic devices) throughout
> the airplane and then checked the signal strength at various locations
> where avionics are installed.  The conclusion was that even at very high
> signal output (4 amps) and at frequencies close to avionics frequencies
> (they tested at 400 MHz and 900 MHz), the signal strength recorded was
> well within the tolerances of the interference specifications to which
> modern avionics have been designed since the 1970s.

Power, RF and other, is specified in watts, not amps.  Specifying amps, 
without a corresponding voltage or impedance, is meaningless.
> 
> And let's also consider one other fact: cell phones, PDAs and laptops
> have been around for 15 years.  I know we've all accidentally left our
> cell phone on in our carry-on bag only to discover it when we land.  I'm
> sure we've all once or twice left the 802.11 transmitter on our laptops
> on during flight.  Now multiply that by millions of passenger-miles per
> day, over fifteen years...if there were a dnager, we'd have more than
> one story by one Delta pilot to show for it.
> 
> Folks, avionics are designed to exacting standards and can handle all
> kinds of interference.  Your humble little cell phone, PDA or laptop is
> not going to crash the plane.  The fact that Lufthansa is offering WiFi
> service on their airplanes in flight should prove this.
> http://wifi.weblogsinc.com/entry/9390742317552618/

Then again, IIRC, Swiss Air had built in game systems, which brought 
down one plane, off Nova Scotia a few years ago.  The crash was caused 
by electrical failure leading to fire.