Do cellphones really interfere with airplane equipment?

Editor’s note: story updated with comment from Transport Canada.

Flight attendants are pretty vigilant about certain rules: raise your seatbacks and tray tables, take out your ear buds during take off and landing, and set your phone to airplane mode. The last request, however, often goes unobserved.

And seemingly, to little effect. After all, how many plane crashes have been caused by cellphone frequency?

But that’s not the point, says one Reddit user.

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“You should really rethink your strategy,” BoilerUp218, who identifies as a former airline pilot, wrote in a thread. “If you eat raw chicken and don’t get salmonella, does it mean that you can’t get salmonella from eating raw chicken? No, it means you got lucky. And so, if you want to gamble on your plane not crashing so that you can get that extra three minutes of text messages in, then keep in mind there are hundreds of other passengers on the airplane who would prefer to probably live their life.”

The user explained that cellphones interfere with navigational equipment especially when landing, which makes it problematic in bad weather conditions because that equipment is what pilots rely on to land the plane safely.

WATCH: In 2013, the U.S. Federal Communications Commission considered lifting its long-time prohibition on making cellphone calls on airplanes, saying it was time “to review our outdated and restrictive rules.”

But is that true?

In 2014, Transport Canada issued exemptions to airlines that could prove through proper testing and demonstration that electromagnetic devices like iPads and laptops did not interfere with navigational equipment. Those exemptions are airline specific, and travellers should check ahead to see if the airline they are flying allows the use of electromagnetic devices.

The use of cellphones to make or receive calls or text messages, however, is still banned during flight.

“The concern we have is in the transmitting portion of cellphones,” says Aaron McCrorie, director general of civil aviation at Transport Canada. “The effort to transmit or receive information can interfere with navigational and communication equipment, and that can have serious consequences on procedures like landing the plane safely.”

“We want to err on the side of caution,” says Melanie Lalonde, Transport Canada media relations representative.

Patrick Smith, a pilot and author of Cockpit Confidential: Everything You Need to Know About Air Travel, admits that while airplane equipment has been designed to protect itself from interference, he’s firmly in the better-safe-than-sorry camp.

“Can cellular communications really disrupt cockpit equipment? The answer is potentially yes,” he said to The Telegraph. “But in all likelihood, no. Aircraft electronics are designed and shielded with interference in mind. This should mitigate any ill effects, and to date there are no proven cases of a phone adversely affecting the outcome of a flight. But you never know.”

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Furthermore, says BoilerUp218, radio interference from phones results in a clicking noise heard in pilots’ headsets — think the noise a speaker makes when a cellphone next to it is about to ring. Those noises could cause pilots to miss important instructions from air traffic control, “which could lead to you flying into a mountain or another airplane.”

“We have had anecdotal reports from pilots who noticed little blips interfering with the landing equipment during a storm,” McCrorie says. “It’s difficult to trace that back to a cellphone being used in the cabin but it is one of the possible causal factors.”

If that isn’t compelling enough, think of the social ramifications of being allowed to use your cellphone on an airplane.

“The minute it can be proven beyond reasonable doubt that phones are safe, a percentage of flyers will demand the right to use them, pitting one angry group of travellers against another, with carriers stuck in the middle,” Smith said.

In other words, the last social space free of cellphone chatter would be gone forever.