[Shop-talk] Cell phones on aircraft (was Compressed Air Lines, RapidAir)

[Randall]

> My phone easily has a range of four miles,

However, those other phones are not inside the same metal skin as the
avionics, and are much further away.  UHF Radio signals generally follow an
inverse cube law, meaning every time you double the distance, the signal
falls by a factor of 8.  If you are 10 feet from the cockpit, and 10,000
feet from the ground, that means the ground signals are 1,000,000,000 times
weaker.

Some years ago, my office computer monitor developed a strange twitch every
few minutes.  Kind of looked like something was arcing in the high voltage
section, as the image would instantly shrink and then grow back to size
somewhat slower.  But replacing the monitor didn't fix it.  Nor did
replacing the video card & cable.  Finally, more by luck than anything else,
I realized the problem was my new cell phone, which I had started laying on
the desk nearby.  Moved the phone 2 feet away, never saw the problem again.

One other point, I've been privileged (?) to ride in the cockpit of some
non-commercial flights.  The radios they use to contact the tower have
simply hideous voice quality.  ANYTHING that adds more audible interference
increases the chance of a mis-communication, and hence the chance of an
accident.  While I'm not privy to the FAA's reasoning, my guess is that
audible interference is more of a concern than disrupting anything
electronically.  

Better safe than sorry, or something like that.

-- Randall