Cell Phones on Planes: The Risks Are Real

08 February 2011 | 03:15 PM ET | Nidhi Subbaraman, SecurityNewsDaily Contributor

Early in January, media baroness Arianna Huffington was reportedly involved in a tiff with the crew of a United Airlines passenger airliner for using her BlackBerry after she’d been told not to. She was escorted off the plane.

A month earlier, “Transformers” star Josh Duhamel was kicked off a flight for the same thing.

The Federal Communications Commission’s regulation banning cell-phone use on aircraft has been in place since 1991, but incidents such as these suggest that passengers aren’t taking the rule seriously.

It’s not hard to understand why. Cell phones have been widely used for 20 years, and a least a few people must accidentally leave theirs on during every commercial flight.

Yet there’s never been a clear instance of cellular signals bringing down a plane. So is there really a danger?

It’s a complicated issue, says David Carson of Boeing, who has chaired a federal advisory committee on the use of electronics on airplanes commissioned by the Federal Aviation Administration (FAA).

For a start, both the FCC and the FAA have a say on the subject. It was the FCC that laid down the original ban, but the FAA’s own regulations now back it up.

“No matter what it is — whether it is putting something new like guidance computers on the airplanes, or a new seat — you can’t do it unless you prove to the FAA that it’s safe to do that, and it can be used in a safe way,” Carson said.

But with the range of cell phones available, and rapidly changing technologies, there’s no practical way to carry out such a comprehensive assessment. Each new phone model would need to be tested, with separate tests for each carrier.

For this reason, the FAA supports the FCC’s blanket ban — with the provision that if the FCC ban were lifted, and an individual model of cell phone type were proven safe for flight, it could be used on a plane.

The FCC’s concerns have less to do with cell phones endangering planes and more to do with how they affect cellular towers on the ground.

“When you use a cell phone on an airplane, you’re using something that’s a terrestrial mobile facility up at 10,000 feet where it can see hundreds and hundreds of cell towers,” Carson said. “The cell system isn’t really set up to handle that very well. It puts a strain on them.”

In 2004, the FCC considered loosening the ban and put out a call for public comment, as most government agencies do before changes in regulations. Then came a surprise — the overwhelming response was against allowing cell phones to be used on aircraft.

Passengers didn’t want to spend an entire flight with “someone yakkin’ on the phone next to them,” Carson said.

That’s one reason the ban stayed in place. Another factor was a study carried out by the RTCA, a Washington, D.C.-based independent non-profit organization established in 1935 and formerly known as the Radio Technical Commission for Aeronautics.

After carrying out a series of tests on the interaction of cellular signals with aircraft navigation systems, the RTCA also recommended that the ban not be lifted.

“They found no conclusive proof that they [cellular signals] would not interfere with the communications and navigation system of the airplane,” Les Dorr, spokesman for the FAA, told SecurityNewsDaily. “What it boiled down to was: There’s no definitive proof one way or another where cell phones do or do not interfere, so the best thing to do is [to] be conservative about our safety.”

Jay Apt, a professor of electrical engineering and public policy at Carnegie Mellon University in Pittsburgh, was part of another study, done in 2006, that told a slightly different story.

Members of his team boarded flights carrying FAA-certified devices that recorded activity on radio frequencies emitted by cell phones.

Over 37 flights, they collected 50 hours of data and documented several cases of people using cell phones even after being asked not to.

The signals the cell phones emitted were strong enough to interfere with GPS signals.

The group also conducted a survey of the Aviation Safety Reporting System, a database maintained by NASA that lets pilots file individual, anonymous reports about flight-safety problems and near-miss experiences.

“There were clear-cut instances where portable electronics interfered with the cockpit and aircraft navigation systems,” Apt said.

Looking at records logged into ASRS up until 2001, the group counted 45 instances where pilots reported that signals from electronics were interfering with communications and navigations equipment.

In every case, after passengers were asked to turn off their electronics, the interference disappeared. In one instance, as a test, the airline crew turned electronic devices back on, and the readings were again thrown off.

But we can turn our cell phones on once we land, right? There’s been a study on that too.

About four years ago, engineers at American Airlines carried out tests with cell phones and stationary aircraft at different places on the tarmac. They tested all varieties of aircraft, manually dialing from cell phones and observing the effects on navigation systems.

“The bottom line of the testing was that they found no interaction with the aircraft instruments on any aircraft type while significant cell-phone activity was taking place,” Tim Smith, part of the media relations team at American Airlines, said in an e-mail.

Since those tests were performed, American Airlines has allowed passengers to use cell phones on their aircrafts while they are on the ground.

“Anecdotally, we have not encountered any cell-phone issues on the ground since allowing the practice,” Smith said.

So will turning on a cell phone in-flight cause a plane crash? Probably not, but there’s a chance that, as with any other device that emits a powerful radio signal, a transmitting cell phone will throw the aircraft navigation systems for a loop.

In terms of safety during flight, Boeing’s David Carson said, the current regulations on cell-phone use work like stop signs at an intersection.

“You can come to a stop sign, and choose to ignore it, and maybe you wouldn’t get hit,” Carson said. “But the more often you did that, the more the likely that someone will be coming from the other side and you’ll get hit. It’s the same thing here.”

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