Smartphones, tablet computers and other mobile devices communicate through a variety of wireless technologies, including Wi-Fi, Bluetooth, GPS and cellular phone links. These radio signals can potentially interfere with a commercial aircraft's electronic systems during flight. To address this concern, mobile device manufacturers developed an airplane mode that turns off the wireless signals but allows the mobile device to be used for approved activities during air travel.
Avionics and Interference
A modern passenger airplane contains complex electronic equipment, called avionics, used for control of the plane, communication and navigation. Some of these systems rely on radio links with control towers and GPS satellites. Personal electronic devices, including cell phones, laptop computers, MP3 players and handheld games, generate radio frequency signals that can interfere with those needed to operate the aircraft safely. While these radio signals won’t shut the engines down, they have the potential to compromise a conversation between the pilot and traffic controllers or interfere with navigation, sending the plane off course. The interference is complicated and erratic, affecting only some of an airplane’s systems some of the time, but the potential threat is serious enough to merit strong precautions.
Because cell phones produce relatively strong radio signals during calls, the Federal Aviation Administration and Federal Communications Commission ban their use in passenger aircraft. As smartphones evolved to run apps, play music and show movies, this created a problem for travelers who couldn’t use them during flights for activities that didn't include radio frequencies. The airplane mode addresses the problem: When you activate airplane mode, it disables the device’s radio signals including Wi-Fi, cellular communications, location services, GPS and Bluetooth. Even with airplane mode turned on, the phone’s microprocessor still generates some radio frequency interference. For this reason, aircraft crew members instruct passengers to keep their cell phones and other portable devices turned off during takeoffs and landings. Use the devices only when the crew informs you it is safe to do so and only in airplane mode.
Activating Airplane Mode
To activate your mobile device’s airplane mode, open its Settings app. On Apple’s iPhone, iPad and iPod, the option to enable airplane mode is on the top of the Settings app’s first page. For Android devices, select “Wireless and Networks” in the Settings app and then tap the airplane mode check box. When you enable airplane mode on an iPhone or Android device, the home screen displays a small icon of an airplane in the same area that shows the battery level and other status indicators. To deactivate airplane mode, use the same Settings app as before and turn the mode off. Even when you are not flying, you can use airplane mode to extend a battery charge. Turning off all the wireless features conserves power.
Airplane Mode Limitations
You cannot receive or place calls on your mobile device when airplane mode is activated. You cannot receive or send text messages or access the Internet. You can use the mobile device to watch videos stored on the device, play downloaded games, listen to music and view and create documents.
Some aircraft operators are repurposing the dedicated air-to-ground frequencies formerly used by seat-back, in-flight phone service to bring the Internet to travelers. These restricted frequencies do not interfere with aircraft avionics. Ask a crew member about the availability of this service.