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Radios Off, Please

Introduction 

We're inundated with people talking on cell phones everywhere we go, but there are still a few places where talking on them is taboo or even illegal. Airplanes are one of the last cell-phone-free zones. For years, the prohibited use of cell phones and the prohibitive cost of seat-back phones have limited conversations on planes to those of neighbors.

Recent advances in technology have begun to open up the possibility of cellular use on airplanes, but just because it can happen doesn't mean it will happen. There is resistance from regulatory agencies, airline workers, and even passengers - at least when it comes to voice calls. Resistance to using phones with the cellular radio off - a so-called airplane or flight mode for playing games, listening to music, and using phones as a PDA - is declining rapidly. Surveys also show resistance to text messaging isn't nearly as fierce as it is to calling, leaving open the possibility of limited cellular service.

Here and Now 

Some airlines have begun allowing the use of cellular phones and other wireless devices as long as passengers can demonstrate the phone's radio is turned off. SAS was the first, but others have followed since.

Until recently there was no easy or standard way for a user to prove his wireless device was not transmitting. However, in October 2004 the Consumer Electronics Association came out with a standardized "flight mode" indicator and guidelines. The guidelines recommend specific language "transmitter disabled" (or another language's equivalent phrase) as well as a graphic to indicate that all radios are off. The symbol can be displayed on a screen, or marked on a device with an LED indicator next to it.

When any radio is on, there is a "transmitter enabled" graphic that should be used as well, which can be supplemented with standard icons depicting the kind of radio that is active (cellular, Wi-Fi, Bluetooth, etc.).

A few manufacturers as well as a number of airlines have declared support for this new standard. Despite kind words from a few US airlines at the launch of the flight mode guidelines last year, none of those airlines have changed their policies to allow the use of cell phones or other wireless devices, even in flight mode. According to a CEA spokesman, a few US airlines, including United, are close to completing a revision of their PED policy.

Manufacturer support for the new standard is less clear. Many manufacturers have come out in favor of a standardized graphic and language, but none have revealed a timeline for implementing them in handsets and other devices.

Safety Issues 

It may be possible to make a call from a plane today simply by turning on your phone, but that could create serious problem for both the airplane as well as carriers.

One theory says that when a phone is transmitting to towers on the ground from 30,000 feet, it is impossible to guarantee that the phone is connected to closest or best choice of cells. The handoff of a call from one cell to another is even more difficult to manage, because an airplane's speed and altitude could move a caller many cells away in just a few moments, creating confusion for the network.

Airplane safety is another critical factor to consider. in 2003 by the UK's Civil Aviation Authority (CAA), compiled a report of all known airplane malfunctions that were attributed to mobile phones. However the evidence wound up being mostly anecdotal, there was no way to prove it was the phones causing the problems. Further weakening the report's impact, many of the incidents were minor at best, such as false luggage compartment warnings.

However since the CAA could not conclude anything from the compiled reports, they did a study to test the effect of cell phone on airplane flight systems under controlled conditions. For a phone to communicate with a tower on the ground while flying, it would need to operate at maximum power. The CAA study determined that the radio transmissions from just a few phones (4 - 5) operating at maximum power in the cabin could create enough interference to affect, at least to a minor but noticeable degree, a planes avionics - the mission critical components which guide and control a plane. A single phone used in the cockpit might be capable of causing the same amount of interference.

Airborne Calling

Gov't Approval 

The US Federal Aviation Administration (FAA) last year established an objective to continue assessment of PED (Personal Electronic Devices) threat. The FAA will study how and whether the operation and transmission of mobile devices affects a plane's systems. They do not expect to draw any conclusions until 2006.

Should the FAA approve the use of wireless devices on planes in the US, the Federal Communication Commission (FCC) has already begun taking steps to make it possible for those devices to communicate with base stations on the ground. It has reserved 4 MHz of spectrum in the 800 MHz band for transmission of wireless communication from air to ground. Currently the FCC has limited use of this spectrum to wireless data, however it has begun asking for public opinion on opening the spectrum up to cellular phone calls as well.

In either case, your phone or laptop / PDA would not be communicating directly with networks on the ground, but with a tiny base station on the plane called a "picocell" that would then communicate to networks on the ground for you. These picocells are the basis for all next generation air-to-ground systems.

Wi-Fi Enters 

Verizon's Airfone - the seatback phone system that Americans are most familiar with - currently works by transmitting between the plane and a network of towers on the ground. Verizon expects to expand the service from voice and dial-up data to broadband data this year. Since Wi-Fi use is still not approved for domestic carriers, users will have to connect via an ethernet or USB cable to a seatback jack. Verizon also expects to offer access to voice over IP (VoIP) phone services as part of this upgrade, however no plans have been announced to extend Airfone to relay mobile phone calls.

Boeing's Connexion system is the first broadband data system installed in planes. It is also the first system that works using a wireless protocol - users connect to the internet over a Wi-Fi base station in the plane in order to get on the 'net. The base station then relays internet traffic from the plane to various satellite networks. Connexion does not support mobile phones, however it does allow calls to be made over VoIP networks.

Although the FAA still considers PEDs a possible threat, it granted Boeing a certification allowing the use of Wi-Fi on planes with Connexion installed. In order to receive this, Boeing modified a 737 for testing and showed the FAA that Connexion did not interfere with the plane's avionic or structural integrity. Other countries' regulatory agencies, including Germany and the UK, have also approved Connexion.

Connexion is currently available on select routes of Lufthansa, SAS, ANA and Japan Airlines. It is also being deployed on El Al, China Airlines and Korean Air.

Cell Systems 

Airbus and SITA have done tests similar to Boeing's using their OnAir picocell system to test interference on Airbus A320 and A340s. OnAir doesn't just offer internet access over Wi-Fi, but mobile phone service as well. They showed that by using picocells, neither Wi-Fi nor cellular radios interfere with avionics on the planes.

These tests, as well as the previous approval of Connexion, may pave the way for mobile phone relay systems like OnAir to make their way onto aircraft. There are a number of technologies competing for airlines' attention should they receive government approval.

OnAir, from Airbus and SITA, is capable of relaying mobile phone calls from GSM, CDMA or W-CDMA handset as well as internet access over Wi-Fi or Bluetooth. An airline can choose which of these options to install or activate. OnAir relays voice and internet through a satellite system - most likely Inmarsat's - to the ground. Airbus estimates the system could be available in commercial airliners in 2006.

Aircell's Broadband System relays mobile phone calls on GSM, CDMA and iDen as well as internet access over 802.11 b and g. Aircell's system communicates directly with towers on the ground, making it a likely candidate for use with the FCC's newly approved chunk of spectrum, which is reserved for air to ground transmission. Aircell expects the system to be ready in 2006.

AeroMobile, from ARINC and Telenor, is built just to relay GSM 1800 and 1900 calls as well as SMS and GPRS / EDGE packet data. Cellular transmissions are relayed from a picocell to the Inmarsat satellite networks. The system is expected to be available in late 2005.

Do We Want It? 

Even if it does receive approval from government regulators, there are strong indications that most airline passengers don't want cell phone calls on planes either, but those who do are probably business travelers, whom the airlines tend to cater to.

A recent survey of airline passengers sponsored by the Association of Flight Attendants and the National Consumers League found that 67% would prefer that a ban on calling remain in place. 21% believe that it's time to allow calls during flight. Even if the ban was lifted, about 80% believe that in flight calls could be annoying at the least, hazardous at the worst.

The AFA / NCL survey above included both casual and frequent fliers, but one of the companies working on flight phone service did a separate survey of European business travelers. Even there support was not overwhelming, only finding "about half" would choose an airline with cell service over an airline without it, however less than a third of those surveyed found the idea of making calls in flight appealing.

Even if calls are allowed on board, cell phone users are likely to find themselves outcasts of the skies. Groups have already recommended that airlines shut off the cellular relay during mandatory quiet times and / or create special cell phone sections like the smoking sections of old.

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