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by Betsy Harter
Nov 1, 2001 12:00 PM
Will rules change
concerning wireless calls on planes?
Early Sept. 11, airline passengers all over the country
boarded their flights like any other day. Many chatted on their wireless
phones. As the doors closed and the pilots prepared the planes for
take-off, flight attendants asked passengers to turn off their wireless
phones until the planes had landed at their destinations.
But on four flights, these phones would offer the last
contact passengers would have with their loved ones. They would be using
their wireless phones to say goodbye.
Later that morning, thousands of stunned people working
at or near the World Trade Center's twin towers in New York City also
reached for their wireless phones to call family and friends after the two
buildings had been attacked by commercial airplanes. The fortunate ones
were able to reassure loved ones that they had made it out of the
buildings safely. The others made their last calls.
The use of wireless phones during the attacks already
has caused some unexpected changes. AT&T Wireless, Nextel and Verizon
Wireless all reported increases in wireless-handset sales immediately
following the attacks, perhaps due to heightened safety concerns. But will
the importance of wireless phones during this tragedy spur other changes
as well?
Calling From 30,000 Feet
Because wireless networks are designed for terrestrial
use, the fact that so many people were able to call from the sky brings
into question how the phones worked from such altitudes.
Alexa Graf, AT&T spokesperson, said systems are not
designed for calls from high altitudes, suggesting it was almost a fluke
that the calls reached their destinations.
“On land, we have antenna sectors that point in three
directions — say north, southwest, and southeast,” she explained. “Those
signals are radiating across the land, and those signals do go up, too,
due to leakage.”
From high altitudes, the call quality is not very good,
and most callers will experience drops. Although calls are not reliable,
callers can pick up and hold calls for a little while below a certain
altitude, she added.
Brenda Raney, Verizon Wireless spokesperson, said that
RF signals actually can broadcast fairly high. On Sept. 11, the planes
were flying low when people started using their phones. And, each call
lasted 60 seconds or less.
“They also were digital phones, and there's a little bit
more leeway on those digital phones, so it worked,” she said.
It helped that the planes were flying in areas with
plenty of cell sites, too. Even United Airlines flight 93, which crashed
in rural Pennsylvania, was supported by several nearby cell sites, Raney
added.
Despite the numerous calls from wireless phones, it was
the hijackers — not interference with the airplane's operating system —
that brought the four planes down. Many in the wireless industry question
whether wireless devices cause problems on board aircraft after all.
“With air travel, you want to take every precaution you
can, but my understanding is that not calling from planes is a bit of a
precaution,” Graf said.
Keith Nowak, Nokia media relations manager, agreed.
“In reality, a cell phone could cause a warning light
not to work, but it wouldn't be anything serious. There's the potential to
cause some effects, but it's generally a preventative measure.”
Change Unlikely
Following the attacks, Northjersey.com reported that the
FAA is rethinking the ban on cell phones while flying. However, it looks
as though any change is unlikely.
“Practically the entire spectrum of options for
improving safety and security are being looked at in the wake of the Sept.
11 incidents, but I can't speculate on whether or not one would be to
authorize the use of cell phones in an emergency, especially because
there's evidence that cell phones can interfere with critical systems,”
said Les Dorr, FAA spokesperson.
Dorr emphasized that the rules prohibiting
wireless-phone use while flying is not actually an FAA prohibition, but an
FCC restriction. The FAA supports that restriction because it's possible
that wireless phones could pose a source of interference to critical
aircraft systems.
“FAA regulations prohibit any device that is an
intentional emitter of radiation, which a cell phone obviously is,” he
added.
According to an advisory on the FAA Web site, the FCC
currently prohibits the use and operation of wireless phones while
airborne. Its primary concern is that a wireless phone, while used
airborne, would have a much greater transmitting range than a land mobile
unit.
“This could result in serious interference to
transmissions at other cell locations since the system uses the same
frequency several times within a market,” according to the advisory.
Because a cellular mobile telephone is capable of operating on all
assignable cellular frequencies, serious interference also may occur to
cellular systems in adjacent markets.
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