How Mobile Phone Services Work During Flights

You've seen it in the grocery store, while driving, and even in movies – cell phones are now part of almost every aspect of our lives. The one place where they haven't been allowed is in the sky. Could the use of mobile phones during flights be the next frontier?

In many regions, this is already a reality. In Europe, mobile phones have been permitted on planes for over a year. However, in the United States, both the Federal Aviation Administration and the Federal Communications Commission prohibit passengers from using their phones on flights due to concerns that phone signals could interfere with both the plane’s systems and ground-based networks below.

Mobile phones have been available on planes since the 1980s, with the debut of the Airfone service, which relied on radio technology. Though the technology is still in use today, in 2006, Verizon, which had acquired Airfone in 2000, announced it would exit the in-flight phone market. The frequencies once used by Airfone were auctioned off to AirCell, which plans to use them to provide high-speed in-flight Internet services.

While early in-flight phone technology was costly to use, newer mobile phone services in other countries are priced more similarly to international roaming fees — typically between $1 and $2 per minute, according to a report by CNN.

In 2007, Emirates Airline became the first airline to allow cell phone use on its planes, as reported by CNN. The airline’s system, provided by AeroMobile, enables passengers to make and receive phone calls and text messages while flying at cruising altitude. Since then, many international airlines have adopted similar services.

How does in-flight phone technology function? What are the safety concerns associated with in-flight mobile services? Check out the next page to learn more.

In-flight Mobile Phone Services Technology

Before diving into in-flight mobile phone services, let's first examine how cell phones function when on the ground.

Despite its name, a cell phone is essentially a two-way radio. However, it operates on a much more advanced level compared to a citizen's band radio or walkie-talkie.

CB radios and walkie-talkies are simplex devices, meaning they rely on just one channel for communication. As a result, only one person can speak at a time on these devices.

In contrast, a cell phone is a duplex device. It alternates between two frequencies—one for transmitting, or speaking, and another for receiving, or listening.

Will regular cell phones work on planes? According to The New York Times, while cell phones can function during the ascent and descent of a flight, their ability to connect diminishes as the plane gains altitude.

An increasing number of airlines are implementing technologies that enable passengers to use mobile services while flying.

As of September 2007, passengers aboard Airbus flights were able to make calls and send text messages from their mobile phones at around 10,000 feet. The service charged $2.50 per minute and 50 cents per message, as reported by the International Herald Tribune.

OnAir, the service provider, uses specialized equipment to route calls and messages through a satellite network, which then connects them to the ground-based network. The flight crew manages the system and has the ability to restrict or disable its use.

Pico cell technology enables passengers to use their personal cell phones on aircraft. These Pico cells are designed to cover very small areas. In terrestrial networks, they are deployed in locations like buildings where signal strength is poor or to enhance network capacity. On an airplane, a Pico cell integrates electronic components with an onboard antenna. Calls made by passengers are transmitted to the central antenna and then relayed to ground-based towers.

Although in-flight cell phone service might be possible, it remains uncertain whether passengers would actually use it. A survey conducted by Carlson Wagon-lit Travel, a travel management company, revealed that 61 percent of business travelers are opposed to using their phones during flights. Consequently, airlines are exploring alternative options to fulfill the communication needs of travelers, such as offering high-speed internet access.

AirCell assists U.S.-based airlines in providing in-flight connectivity. Their service enables passengers to browse the internet, check emails, send attachments, and even access their office networks from an altitude of 35,000 feet.

Numerous airlines, both domestic and international, are also pursuing this option.

In December 2007, The New York Times reported that certain American airlines were offering in-flight internet services. JetBlue Airways provides instant messaging, while Virgin America and Alaska Airlines offer web access. Experts predict that in-flight web access will become widespread in the coming years.

American Airlines revealed plans to test high-speed internet service for passengers aboard its Boeing 767-200 aircraft in 2008, primarily on international routes. The system will utilize three external antennas mounted on the plane, relying on a network of cell towers across the United States for connectivity.

According to American Airlines officials, the service is designed for customers who depend on PDAs and laptops for accessing real-time information and staying connected.

Although wireless web access could potentially enable phone calls, most airlines have stated that they have no intention of allowing voice communications. Concerns over the disturbance caused by cell phone conversations, which could annoy other passengers, led to this decision. On the other hand, browsing emails or surfing the web quietly is considered less disruptive.

Beyond the increase in conversations, what other safety issues are associated with in-flight mobile phone services? Turn to the next page to learn more.

Safety Concerns with In-flight Mobile Phone Services

In the United States, both the Federal Aviation Administration and the Federal Communications Commission oversee the regulation of mobile phone usage on airplanes.

Safety issues arise for both mobile networks and aircraft when traditional "terrestrial" cell phones are used during flights.

Cell phones emit radio signals, and government agencies are concerned that these signals might interfere with critical aviation systems like communication devices or navigation equipment, both of which rely on radio frequencies.

In the mid-1980s, as the first commercial mobile phone networks were launched, the U.S. government introduced regulations banning their use on commercial flights. These rules were put in place due to the aforementioned concerns.

On September 11, passengers ignored these regulations, using both Airfone-style and traditional cell phone technology to contact loved ones and law enforcement officials. Another significant safety concern, however, is the possibility that terrorists might exploit a cell phone signal to detonate an onboard bomb.

In the spring of 2007, the U.S. government reaffirmed its decision to uphold the ban on in-flight mobile phone usage. An FAA spokesperson stated that the agency was responding to public anxiety, fearing that mobile phone signals might interfere with the aircraft's control systems.

These concerns may be valid. The Telegraph reported that between 2000 and 2005, the British Civil Aviation Authority documented up to 20 incidents where mobile phone usage was linked to aircraft malfunctions.

Despite these issues, the European Aviation Safety Agency recently granted approval to OnAir to start offering in-flight mobile phone service. The system employed by the company uses phones that are less powerful than standard mobile phones, designed to minimize interference with aircraft controls.

Several European airlines are planning to introduce mobile phone usage on their flights. However, this issue remains controversial, as highlighted in an article by The Telegraph.

The FCC prohibits the use of cell phones operating on the common 800 megahertz frequency, along with other wireless devices, due to potential interference with ground-based wireless networks. This issue arises because airplanes, traveling at speeds of several hundred miles per hour, quickly move from one mobile phone tower's coverage area to another.

The use of mobile phones and other portable electronic devices, such as iPods or portable radios, could also disrupt the aircraft's communication and navigation systems. For this reason, the FCC bans their use during flights.

Cell phones are of particular concern because they are designed to emit signals strong enough to be received over long distances.

The FCC has, however, approved regulations allowing in-flight voice and data services, such as broadband internet, using dedicated frequencies that were previously allocated to services like Airfone.

The FAA's fact sheet on the matter highlights that the agency's primary concern is the uncertainty. The signals emitted by mobile phones and other devices might, over time, affect vital aircraft systems. While the FAA's regulations limit most devices, there are exceptions, such as voice recorders, hearing aids, heart pacemakers, and a few others.

Generally, the FAA advises airlines that most personal electronic devices are safe to use once above 10,000 feet. This is because any potential interference they could cause would be more troublesome at lower altitudes.

Certain cell phones allow users to switch to 'airplane mode,' which disables the phone's transmitter but still allows the passenger to access other features, such as their calendar or games.

Which airlines offer in-flight mobile phone services, and which provide only limited options? You can discover more on the following page.

Introducing In-flight Mobile Phone Connectivity

Air France initiated a limited trial service in late 2007, permitting passengers to send and receive text messages and emails.

The airline intended to allow voice calls starting within the first three months of 2008, but stated it would monitor callers "to ensure passengers' comfort and well-being," according to Network World.

Passengers are permitted to use their phones only when the aircraft reaches an altitude of 10,000 feet or more.

Some airlines, particularly those in the United States, allow restricted use of cell phones while on the ground. For instance, American Airlines and its affiliates permit phone use during taxi-in, signaled by an in-flight announcement. However, phone usage is prohibited during flight due to regulations set by the FCC.

A number of airlines are experimenting with an alternative way to use cell phones — as boarding passes. In late 2007, the International Air Transport Association approved a system for airlines to send barcode images to passengers' phones. These images can be scanned by gate attendants just like traditional paper boarding passes. These technological advances, projected to begin in 2010, indicate that airlines and mobile phone technology will continue to collaborate in the future [source: Into Mobile].

Alongside regulations, other factors such as billing uncertainties, customer service concerns, and service availability hinder airlines from allowing full mobile phone usage during flights.