Commercial airlines prohibit the use of cell phones in planes, but wireless industry executives are now calling the ban into question.

U.S. mobile carrier Sprint PCS is in favor of loosening the rules of on-board cellular communication because "there is no conclusive evidence of interference in the air or on the ground," Oliver Valente, the firm's Chief Technology Officer, told the New York Times.
'No evidence'

Passengers on the hijacked planes that crashed in Pennsylvania and Washington last week made mobile phone calls to their loved ones before they died -- phone calls that are technically illegal in the United States.

Airborne cell phone use is prohibited because of concerns that radio signals could interfere with critical on-board instruments.

"Things like compact disc players and wireless equipment -- they all emit frequencies and some of them actually have an effect on airplane navigation systems," said Gartner Group mobile analyst Nick Ingelbrecht.

Bit there is little, if any, evidence to prove that in-flight cell phone usage interferes with the communication systems of an aircraft.

"There is no evidence per se," Craig Ehrlich, Group Managing Director of Hong Kong mobile carrier Sunday, told CNN.

"There are no surveys or reports. It's a precaution."

The U.S. Federal Communications Commission banned the use of wireless devices not over concerns about airplane safety but rather the potential interference for ground-based communication networks, the New York Times reported.

Experts say cell phones used at high altitudes may contact a variety of base stations, preventing customers within the base station range from using the same frequency.

Though mobile phones are not designed for air-to-ground communication, a call can get through if a direct line to a cell tower is available.

The dramatic cellular calls made by last week's hijacked passengers did not sway the U.S. Federal Aviation Administration (FAA) to change its stance on in-flight mobile usage.

"The possibility of any disruption to an aircraft's communications cannot be tolerated," FAA spokesman Hank Price told reporters last Thursday.

Commercial airlines in Asia are likely to continue to enforce a blanket ban on in-flight cellular calls.

"It's been a well accepted rule in the last 10 years on cell phones, said Sunday's Ehrlich.

"Cell phones have always been restricted on airplanes. I don't know why it would be reopened."(from CNN)