PHOTO: ARINC

This May, the U.S. Federal Communications Commission plans to auction off radio spectrum to jump-start new services to let you talk on your cellphone and surf the Web while you're on an airliner. Regulators in Europe and Japan are heading in this direction, too. While this first U.S. auction is for the proposed broadband services only, the FCC's overall move in the direction of relaxing the ban on the use of personal electronics during flight has made some folks happy—and many others worried.

Happy, obviously, are the companies that will supply the technologies to make this happen, as well as those travelers who consider cellphones and e-mail to be organic extensions of their central nervous systems. Not so happy are flight attendants, who feel that cellphones and other portable electronic devices have already complicated their jobs. And a lot of passengers aren't thrilled about the prospect of listening to someone blather on for 10 000 kilometers.

Then there's the safety issue. Concerns about the potential risks posed by electronic devices led to the current ban on in-flight cellphone and wireless network use, which has been controversial and rarely well explained. IEEE Spectrum reported on this topic some 10 years ago in "Do Portable Electronics Endanger Flight?" [September 1996]. The article discussed an important 1996 study done by the Washington, D.C.–based nonprofit group RTCA Inc., which mobilizes companies and agencies to take on important aircraft safety issues and make recommendations to the Federal Aviation Administration, the final authority on U.S. aircraft safety. This study concluded that, while the risk posed by personal electronics was low, regulation was essential because there were still many unknowns.

Ten years later, there are still many unknowns. The basic concern is the same—that radio frequency emanations from the devices can interfere with an aircraft's critical flight control and navigation systems. Unfortunately, and surprisingly, the available hard quantitative data about the impact of personal electronics on avionics has remained inconclusive, and much of the rest is anecdotal and can't be reproduced in a test setting. What is new now, and makes the need for useful data increasingly urgent, is the accelerated interest in allowing devices to be fired up during flight and the rapidly expanding universe of new consumer technologies that travelers want to use on board.

Bill Strauss and three colleagues from Carnegie Mellon University, in Pittsburgh, underscore the need for more research—in particular, live research aboard actual flights—in their article "Unsafe at Any Airspeed?" in this issue. They developed a portable detection system, and with the permission of several airlines, followed furtive cellphone use by passengers during flight. They confirmed that it is possible to distinguish individual portable electronic signals and thus gain a better appreciation of their potential impact on that plane's critical flight systems. The authors call for more—a lot more—in-flight measurements of the radio frequency environment, as well as for real-time monitoring by flight crews of the use of personal electronics by passengers.

In the meantime, RTCA expects to release the results of a new study—its first in a decade—by December of this year. It is supposed to detail official testing procedures for assessing the risk of interference from personal electronics on aircraft and even give advice for dealing with passengers who become irate when asked to turn off their toys.

More data will become available from plane makers and from the carriers themselves. Boeing and AirBus have both been conducting tests on the emissions of personal devices. American Airlines, to pick one example, has tested Qualcomm's pico cell in-flight technology on some of its planes. Later this year, TAP Portugal and the British carrier bmi are going to conduct three-month trials of a voice-and-text service being rolled out by a company called OnAir. If it works out, it will go fleetwide (for TAP and bmi) in 2007. OnAir and both carriers have indicated they will be collecting interference data during these tests. Like it or not, wireless technology will soon become a permanent feature of aircraft cabins. Tests like these may help determine with some conclusiveness whether or when it is dangerous for us to phone home from 20 000 feet.

In the meantime, we believe the current ban should be kept in place while data are collected and analyzed and while the technical issues surrounding the setup of these networks in the air are sorted out. What do you think? Write to us at spectrum@ieee.org or visit our Web site poll at http://www.spectrum.ieee.org.