"Devices change faster than the rules"

Friday, March 19, 2004

Devices change faster than the rules  
By Matthew L. Wald
The New York (NY) Times

 
WASHINGTON - Consumers are not the only ones impressed by the
proliferation of new portable electronic devices. So is the Federal
Aviation administration - but not favorably. The technology is changing
faster than air safety rules, according to experts at the agency, the
airlines and elsewhere, who are scrambling to keep up.

Wi-Fi cards, wireless modems, hand-helds with wireless e-mail service
and even cellphones with games are all what the FAA calls "intentional
emitters," devices that put out radio energy at a variety of
frequencies. Passengers are carrying them onto planes that have long
relied on radio navigation beacons on the ground; lately, the planes
also need signals from fainter sources orbiting Earth, the Global
Positioning System satellites. And the planes often have their own
wireless systems for equipment that was added after they were built,
like emergency lighting along the aisles.

Interference between passengers' devices and the planes' systems is
difficult to gauge and probably rare, experts say, but the possibility
of stray signals is stirring anxiety.

"It is thorny, and it gets messy fast," said William Winfrey, a
specialist in advanced technologies at Delta Air Lines. Winfrey is a
co-chairman, with a Boeing expert, David Carson, of a committee
established last year at the request of the FAA to explore the problem.
Scores of experts from airlines, aircraft equipment makers and consumer
electronics companies have been meeting since early 2003 and hope to
issue recommendations in about 18 months.

Yet new products are entering the market so fast that the committee's
recommendations will be quite broad rather than tied to specific
products, Winfrey said.

While travelers may know that cellphones are signal producers and comply
with rules banning their use in flight, their understanding of the risks
posed by other devices is fuzzier. Passengers with laptops equipped with
Wi-Fi cards may turn on the laptop without grasping that it is
broadcasting, looking for an access point. Some may turn on a wirelessly
equipped hand-held to look at a calendar and forget that it, too, is
radiating.

The seriousness of the problem is hard to gauge. Winfrey and Carson are
not certain that there has ever been a problem in flight that was traced
directly to electronic interference originating on board. But the idea
haunts safety experts.

In theory, all devices are putting out radio frequency emissions only in
the ranges assigned to them by the Federal Communications Commission and
thus should not interfere with each other. But electronics experts worry
about signals straying outside the assigned range. Those emissions would
not have to be large to cause a problem. Signal strength from GPS
satellites is in the range of one-billionth of a watt at the receiver,
so even a faint competing signal could interfere.

On the ground, there are also potential safety problems, Carson said.
Hand-held electronics might interrupt a transmission between a cockpit
and the control tower, for example. If a tower controller issued a
clearance for a taxiing plane to cross a runway and then revoked it but
the latter transmission was not heard, the result could be catastrophic,
he said.

While the scheduled carriers have flight attendants who enforce a ban on
using wireless devices at high altitudes, and on using any electronics
below 10,000 feet, charter operators of planes large and small often
tell their passengers to feel free to use cellphones, wireless modems,
two-way pagers and similar devices.


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