Are Cell Phones on Airplanes a Danger?


March 3, 2006 -- -- Are cell phones and other personal electronic devices safe to use on airplanes?

It depends who you ask, but a new study conducted by researchers from Carnegie Mellon University and featured in an article in technology magazine IEEE Spectrum, says they could be.

"The data support[s] a conclusion that continued use of portable RF-emitting [radio frequency-emitting] devices such as cell phones will, in all likelihood, someday cause an accident by interfering with critical cockpit instruments such as GPS receivers," the article said.

The research is believed to be the first of its kind and comes as the FCC is soliciting opinions from the public about allowing cell phone use in airplane cabins.

The public is pushing for it, but could legalizing cell phone use and other portable electronic devices on airplanes put passengers at risk?

"We're not saying we've got a crisis on our hands," said Granger Morgan, one of the researchers. "We're just saying that, you know, as more and more wireless devices get on more and more airplanes, sooner or later we're going to have a problem."

With the permission of participating airlines, which insisted on remaining anonymous, Morgan and colleagues Bill Strauss, Jay Apt and Daniel Stancil used a small suitcase with some technical instruments and a laptop to monitor RF activity on 37 commercial flights.

They found that there was indeed a lot of activity and concluded that such activity may interfere with navigational equipment at a crucial point in a flight.

The authors point to a NASA study that looked at the effects of a specific Samsung cell phone that some pilots had complained had caused their onboard GPS receivers to lose satellite lock.

"It reported that there were emissions in the GPS band capable of causing interference," the article said. "Disturbingly, though, they were low enough to comply with FCC emissions standards.

"Our data and the NASA studies suggest to us that there is a clear and present danger: Cell phones can render GPS instrument useless for landings."

Because pilots increasingly rely on GPS technology to aid in landings, such interference could be potentially catastrophic.

According to the article, there are mountains of anecdotal evidence showing electronic devices can have a dramatic effect on onboard equipment.

"There have -- as we said in the article -- been some events that are suggestive," said Morgan. "And there have certainly been cases where the navigation system seems to be off, and they go back and ask somebody to turn off something and then it recovers and then they ask him to turn it back on, and then the problem re-occurs."

As an example, Morgan and his colleagues point to an alarming incident where the flight crew of an unnamed airline experienced a 30-degree navigational error that was immediately corrected after a passenger turned off a DVD player.

Perhaps more frightening is the fact that the error recurred when the passenger was asked to turn the device back on.

"Game electronics and laptops have been the culprits in other reports in which crew verified in the same way that a particular PED [personal electronic device] caused erratic navigation indications," the article said.

In a survey the researchers conducted with the help of a travel agent, they learned that most people believed cell phones are illegal on airplanes to force passengers to use the seat-back phones already on board many airliners, at bloated prices.

The truth, said Morgan, had nothing to do with profits or safety, but everything to do with keeping the system from overloading.

Talking on a cell phone at altitude means you're moving from tower to tower at a rate that can cause chaos in cellular networks.

But even so, that was an Federal Communications Commission rule, not a Federal Aviation Administration rule. And it seems that even today, the two agencies are not communicating on what the rules for personal electronics should be.

"When the FCC set up to make rules, they didn't really particularly worry about airplane interference and, you know, 30 years ago that wasn't a problem," said Morgan. "But today, with everything in the world wireless and all of it on airplanes all the time, it's time to start paying attention to each other and coordinating."

One of the big complaints from critics of the industry is that the two agencies do not communicate on any meaningful level and that's led to FCC rules that conflict with FAA interests.

In fact, former pilot and columnist John Nance, says that the first substantive communications between the agencies was over the recent decision to consider allowing cell phone use on airplanes.

But Nance believes that as long as these devices exist and continue to become more and more common and portable, there's no way to keep them from being used.

"You need to either completely and totally ban the presence of electronics on an airplane -- which is next to impossible -- or you have to do the opposite," said Nance. "You have to guarantee that the instrumentation cannot be affected by these signals."

There are lots of theories on how to do that.

One of the solutions the researchers suggested was to have an RF monitor onboard the aircraft so the flight crew can monitor activity.

"If flight crews or airliners had RF detectors, then they could take corrective action when they noticed strong electromagnetic emissions," said the article.

While Nance thinks the idea is original, he doesn't think it's the answer.

"You're in the middle of a tough approach, if the RF interference really does have a potential for messing up the GPS, you don't have time at 300 feet, at 150 miles an hour approaching a far-shotted runway to get on the P.A. to tell people to turn off stuff cause the RF monitor went off," he said.

Nance says you'll never keep people from carrying and using their devices regardless of what they're told, and instead suggests hardening the craft's avionics against any kind of interference.

"If they don't think they can do this then they'd better check with the military, because the Navy's been doing this for years," he said. "They've got gigantic radars they've got to protect against, they've got all sorts of RF interference they have to harden the airplane against and all of their avionics are hardened."

Though Nance admits the story about the DVD player that affected an aircraft's GPS system gets his attention, "it's not a cell phone."

Ultimately, Morgan believes this is a cautionary tale of, "Be careful what you wish for."

He admits that air travel has become so safe, that researchers and safety experts are left to ponder very low-risk threats, like these.

But Morgan says just because a cell phone call at 40,000 feet has yet to be proven as the cause of fatal crash, doesn't mean we should be jawing away in the skies.

"There isn't one [crash] that you can clearly nail down, but if you're prepared to just keep on gambling, then sooner or later one [plane] probably will fall out of the sky and I at least think it's not worth that gamble," he said. "Low probability multiplied by a huge number of flights will lead to accidents."

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