Effective December 12, 1991, the Federal Communication Commission (FCC) prohibited the use of cellular phones while an aircraft in airborne. "Airborne" is defined as the time an aircraft is not touching the ground.
FCC Regulation 22.925 requires all cellular telephones to be turned off when an aircraft leaves the ground.
If a cellular phone is installed in an aircraft, the following notice must be posted on or near each cellular phone:
The use of cellular telephones while this aircraft is airborne is prohibited by FCC rules, and the violation of this rule could result in suspension of service and/or fine. The use of cellular telephones while this aircraft is on the ground is subject to FAA regulations.
If the aircraft is not airborne, the use of a cellular telephone is permitted unless the aircraft's operator or pilot in command determines its use will interfere with the aircraft's communication or navigational equipment.
Cellular phones and your aircraft communication equipment are somewhat alike. Both use frequencies that are "line-of-sight" and could travel great distances. Additionally, both can access multiple antennas (much like unicom). At altitude, using a cellular phone can severely disrupt cellular service.
The penalty for violating this FCC regulation can reach up to $10,000.
Some cellular phones are authorized for airborne use; however, they are not your typical $29 special. One manufacturer is AirCell (214/239-5464).
And, of course, you can always call AOPA experts for help or advice with any aeronautical problem:
AOPA Pilot Information Center