tony roberts wrote in news:indiacharlieecho-
15CF69.22341329122006@shawnews:

It is an FCC rule because cellphone tower are designed to
pick up a limited number of calls and at altitude the towers
are over-loaded.

I don't understand this.
Consider that many new headsets actually have a cellphone interface.

and consider that here in Canada it is not illegal, and I use mine lots
- plugged right into my headset.
I don't understand how it could be legal here if it really did overload
towers. So what is the REAL reason?

Cell phones would not be restricted according to the FAA in VFR conditions,
or in IFR if the electronic device was determined not to cause
interference.

I haven't seen it myself, but I was told that there was a "MythBusters"
episode where the guys demonstrated that certain cell phones interfere with
the ILS, causing the needle to deflect at least 50' to one side of the
runway.

For a very long time, I believed that the real reason that the airlines
made you turn off your cell phones and electronic devices on takeoff and
landing was because they wanted your undivided attention while they show
you how to buckle your seatbelt and pull the rip cord on your life vest.
But I could also see where if it is truly interfering with ILS equipment it
would need to be off on final...

"§ 91.21 Portable electronic devices.
(a) Except as provided in paragraph (b) of this section, no person may
operate, nor may any operator or pilot in command of an aircraft allow the
operation of, any portable electronic device on any of the following U.S.-
registered civil aircraft:

(1) Aircraft operated by a holder of an air carrier operating certificate
or an operating certificate; or

(2) Any other aircraft while it is operated under IFR.

(b) Paragraph (a) of this section does not apply to—

(1) Portable voice recorders;

(2) Hearing aids;

(3) Heart pacemakers;

(4) Electric shavers; or

(5) Any other portable electronic device that the operator of the aircraft
has determined will not cause interference with the navigation or
communication system of the aircraft on which it is to be used.

(c) In the case of an aircraft operated by a holder of an air carrier
operating certificate or an operating certificate, the determination
required by paragraph (b)(5) of this section shall be made by that operator
of the aircraft on which the particular device is to be used. In the case
of other aircraft, the determination may be made by the pilot in command or
other operator of the aircraft."