TORONTO – Alec Baldwin was recently kicked off an American Airlines plane for using his cell phone to play a game – Words with Friends – while the plane sat, unmoving, at the terminal before take off.
Alec Baldwin, a prolific Twitter user, took to social media to vent his frustration, saying it would be his last flight on American Airlines – despite them showing 30-Rock, the show he stars in, as in-flight entertainment.
American Airlines, the airline involved, has a policy of not allowing any use of cell phones on flights
Does Alec Baldwin have a point? Does using a cell phone on a flight actually interfere with electronic equipment on airplanes, or is that just a myth?
We spoke with Assistant Professor, Dr. Sean Victor Hum, from the Edward S. Roger Sr. Department of Electrical and Computer Engineering at the University of Toronto to find out if cell phones can interfere with airplanes and what airlines have to worry about while cell phones are on-board.
Is it possible for electronics – such as cell phones – to interfere with planes?
Theoretically, it is possible for an electronic device to interfere with another electronic device, especially if one of them produces emissions. Such emissions can be purposeful (e.g. cell phones are designed to emit signals) or as a by-product of the functioning of an electronic device (e.g. a DVD player, while not designed to emit radio signals, may still produce them indirectly because of the operation of high frequency electronics inside the DVD player). Hence, airlines usually ask that during critical operations such a takeoff and landing, that all electronic devices are powered down to prevent any possible interference with aircraft electronic equipment.
How does this interference occur?
The interference happens because emissions from electronics can be picked up by other electronics. To give an example, many aircraft use GPS to aid in navigation nowadays. If there were an electronic device producing emissions in the same band as GPS signals, this would interfere with the GPS’s ability to accurately determine the position, heading, etc. of the aircraft. Hence, pilots and aircraft systems could be presented with incorrect information from that GPS, because of the interference.
Though they theoretically can affect an airplane’s electronics, is it likely to happen?
There is the question of if controlling the use of electronics on an airplane is necessary. The emitted radio power produced by cell phones, etc., is relatively low. But given the mission-critical nature and great deal of dependence on electronic navigation/communication equipment on aircraft, I would think that carriers would choose not to take a chance with passenger safety. To determine whether emissions from electronics is truly “safe” or not would take a monumental study and measurements of every aircraft system to determine if interference is quantifiably an issue or not. This is obviously a large undertaking.
How severe could the interference be?
The severity of this interference process depends on the strength of the received interfering signal. This basically depends on two things: the transmitting power of the interfering device, and the distance between the interfering device (e.g. cell phone) and device being interfered with (e.g. GPS). While cell phones produce relatively low-power signals, the close proximity of cell phones to aircraft systems when passengers are on board is the reason these are deemed the most critical (and controllable) source of interference on the airplane. Distance plays the biggest role here. While there are transmitters outside the aircraft that produce much stronger signals (e.g. cell phone and broadcasting towers), the signals are so weak by the time the reach the aircraft that they have limited ability to cause interference. This is because the power of a radio signal decays with the inverse of the square of the distance; so if I double the distance between two points, the amount of interference received is actually quartered.
Even if cell phones couldn’t interfere with planes, would it be a good idea to allow full use of cell phones on planes?
A point worth considering, not related to interference, is if allowing cell phone use on aircraft is really good for the carriers anyway. Most carriers are increasingly concerned about air-rage incidents, which I offer might increase if people were allowed to chatter away on cell phones for long periods of the flight. A worthwhile question is if the carriers might be managing that other form of “interference” to mitigate such incidents.
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