Pick Peat!

Probably nothing — people forget to turn off their cell phones, laptops, games, and music players all the time.

However, “probably nothing” is more risk than the airline industry is willing to accept, and for good cause:  you don’t want things going wrong on a plane that’s packed with people and thousands of gallons of fuel, all travelling at hundreds of miles per hour.

So, what could happen as a result of operating portable electronic devices on an airplane?

Here’s the general idea:  all electronic devices create and absorb radio waves.  They say so, right on the package!  Look in the manual for pretty much anything that takes batteries, and you’ll find a notice that says something like:

“This device complies with Part 15 of the FCC Rules.  Operation is subject to the following two conditions: (1) this device may cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.”

A perfect example of this interference is the weird buzzing that comes from a speaker sitting close to a mobile phone.  That buzz represents radio waves emitted by the phone: they’re absorbed by the wiring and are converted into electrical pulses, which get amplified and sent to the speaker.  

All computers operate on pulses of electricity, so it’s easy to see that radio waves and computers might interfere with each other.  Since commercial airplanes depend on computers for almost everything, you can understand why interference from electronic devices is considered a bad thing!

Of course, the airline industry and the FAA (Federal Aviation Administration) are all very aware of this issue.  All of the computer and communication systems that go into commercial airplanes are thoroughly tested in the presence of all sorts of electromagnetic radiation, including pretty much every kind of portable electronic device you can buy.

In reality, the risk that your cellphone or laptop could crash a plane is extremely low, bordering on impossible.  The airline industry knows this, and the FAA knows this.  

So why can’t you use your phone on an airplane? 

That’s all about the FCC — the Federal Communications Commission.  The problem is that mobile phones in airplanes have the potential to disrupt mobile phone networks on the ground.

Mobile phone networks are designed for people who are on the ground, where the signal from your phone is absorbed or reflected by the things around you — buildings, cars, trees, other people, etc.  Mobile phone towers have sophisticated systems for detecting your phone, amplifying your signal, handing you off to other towers as you move, and so on.  Even when you’re not using the phone, it’s still tracked by the network so that you can receive calls.

The whole mobile phone network is geared towards providing service to people on the ground.

If you and your phone are flying over a city, the signal from your phone isn’t blocked by buildings, cars, trees, or anything else.  Just like you can see further when you’re up higher, your phone signal can also travel further.  In theory, you could be tracked by hundreds of towers at once as you zoom by at six hundred miles per hour, causing a fair amount of confusion in the network.

That’s the theory, anyway.  The FCC and FAA haven’t found conclusive evidence that mobile phones in airplanes can significantly interfere with their systems or ground communications.  Never the less, both the FCC and FAA operate on the principal of “dangerous unless proven otherwise.”  It’s not an unreasonable position to take, given what’s at stake.

Other than mobile phones, airlines have a fair amount of flexibility about what electronic devices they allow when the plane is above 10,000 feet.  For example, wireless Internet access has become available on many airplanes.  I’ve video conferenced with my wife while she was at 30,000 feet over the Atlantic.  How cool is that?

So what about under 10,000 feet?  What’s special about taking off and landing?

Taking off and landing are the two most dangerous things that a plane does.  Bird strikes, collisions with other planes, sudden gusts of wind, engine and landing gear malfunctions — the list of bad things that can happen when you’re near the ground is huge.  Banning electronic devices during that critical time removes one of the potential risks from the situation.

The other reason is that if something does go wrong, you’ll need to get off the plane in a hurry.  Your flight crew’s biggest responsibility in an emergency is to get everyone off of a plane within 90 seconds.  Statistically speaking, after 90 seconds, the game is over.  That’s not a lot of time to evacuate a large airplane, so it’s critical to remove obstacles and distractions— hence the litany of seat backs, tray tables, properly stowed baggage … and turning off electronics.

So what happens if you fail to shut down your portable electronic device during landing or takeoff?

You probably won’t crash the plane, but your flight attendants won’t be pleased.  It’s best to follow the instructions, if only for the sake of civility!