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Airline Mismanagement

We've become accustomed to the exhortation to 'turn off everything with a power switch' before the plane pushes back from the gate.

But is there really a valid need to do this?  What would happen if someone forgot to turn something off?

 
 
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Is There Any Danger Using Electronic Devices on an Airplane?

Do we really need to 'turn off all electronic devices' prior to take-off and again prior to landing?
 

Lightning strikes a plane without harming it

A plane can safely withstand a lightning strike of hundreds of millions of volts and tens of thousands of amps.

But turn on your iPod and the plane might lose control, crash and burn?

Really?

 

 

Electronics - and access to them - are becoming ever more inseparably a part of our normal lives.

Everywhere, that is, except in airplanes, where some things are never allowed to be used and others are only allowed to be used above 10,000 ft.

We're told that FAA regulations prohibit such devices, and we're lead to believe that they may dangerously interfere with the plane's operation.

But is any of this actually true?  Let's carefully dissect the disinformation and see what the reality actually is.

As you know, the airlines have varying degrees of restrictions on the use of portable/consumer electronic devices on planes.  These restrictions are usually claimed to be due to FAA regulations, and due to concerns that the electronic items may interfere with some of the plane's own electronics - either the instrumentation or perhaps even the actual plane's controls.

Let's first look at what the FAA says, and then from that reference point, let's consider the validity of the airlines' concerns about portable electronic devices, then at the sense (or nonsense) of the restrictions they impose on us.

Does the FAA Regulate Using Electronic Devices?

How often have you heard the flight attendants announce 'FAA Regulations require you to turn off all your electronics before we can close the door and push back from the gate'?  Or 'Due to federal regulations, we must ask you to turn off all electronics now and leave them off until we have parked at the gate after landing'?

Is this really something the FAA requires?  Or are airline flight attendants lying to us every time they make this claim?

Here is the relevant FAA regulation about using electronics on flights.  To save you the need to carefully read through it all, it basically says the airlines are free to decide for themselves what they will and will not allow on flights, and under what conditions they will allow them.

It talks about prohibiting some devices during take-off and landing, and about lesser restrictions below 10,000 ft, but try and find a specific list of prohibitions or restrictions, and you will fail, because the FAA doesn't provide one.  That is up to the airlines themselves.

Try and find where it says 'All devices must be turned off before you can shut the cabin door and start the engines'.  Try and find where it says 'everything must remain off until stopped at the jetway after landing'.  You won't find either such requirement, because they doesn't exist.

So, there is no FAA regulation that forces either the airlines or us to do anything.  However, there is an FAA regulation which says the airline can decide what you can and can't do (and a different regulation requiring passengers to follow the normal usual instructions/orders of cabin crew) - but that is a very different thing, and you don't hear the flight attendants saying 'FAA Regulations say we can decide whatever we like about when and if you use electronic devices, and so we've decided to make you turn them off now', do you.

If you have spare time on a flight, take a copy of the above FAA statement and ask the flight attendant which FAA regulation requires you to turn off your electronics.  When they say they don't know, show them the FAA statement and ask them where it is in that.

The Theoretical Problem of Interference

Most modern electronics emit very small amounts of radio energy, even if they don't have a radio transmitter in them.  Furthermore, some types of modern electronics can be influenced if they inadvertently are bombarded with radio energy - they may get confused and the radio signals received can interfere with the internal signals already traveling within them.

So therein lies the potential for interference.  You may have sometimes noticed it yourself, perhaps when your cell phone is receiving a call, and if it is close to something like a radio or a regular phone you might hear some noise through the radio.  That is of course an extreme example of a device designed to transmit interfering with a device designed to receive, but there is a theoretical potential for devices not designed to transmit to interfere with devices not designed to receive as well.

The Reality of Interference Problems on Planes

So, now we understand the theory behind the concern, how valid is the concern?  More to the point, are there known problems where electronics actually really truly do interfere with airplane electronics?

And that is where we start to move into a very unclear area.  Scientific method says that you need to be able to repeatedly recreate an identical given outcome from an identical set of inputs in order to have a proven causality.  We are unaware of any repeatable proven definite link between any type of regular consumer electronics on a plane and any type of problem with the plane.

It seems possible however that these random glitches are becoming more common.  Some 'experts' claim this is due to an increase in portable consumer electronics being used in the airplane cabin.  An equally likely explanation is that airplane control systems have become vastly more complicated, themselves, and are now operated by computers rather than by humans; by electronics rather than by cables and hydraulics.

What has happened is that from time to time, planes will act unpredictably and do strange things for no apparent reason.  The auto-pilot might suddenly reset itself, or switch off, or perhaps decide to push the plane's nose down and dive towards the ground - something that is alarming at 35,000 ft and downright deadly at 350 ft.

Greater Danger at Low Altitudes

This last point is a key point, and is the reason why airlines are very negative about any electronics being on during the early and final moments of a flight, while reluctantly tolerant of them while the plane is above 10,000 ft.  Above 10,000 ft, the pilots have more time to respond to anything nasty that happens, and so the airlines are prepared to expose themselves to some degree of risk, but the closer to the ground, and the slower the plane is flying, the less the margin for error.

No-one really knows what causes these occasional semi-random glitches.  And we're surely all familiar with similar sorts of glitches in electronic items at home - bugs in computer programs, phones and MP3 players that sometimes have to be reset, and so on.  Even, increasingly, faults in the 'operating systems' in cars that require you to turn the car off then on again.

Better Safe than Sorry?

In none of these other situations do we ever consider that the problem may have been caused by the phone in our pocket, or the Kindle in our bag.  But usually, in such other cases, the potential range of outcomes from such a problem does not extend to an airplane possibly falling out of the sky, killing hundreds of people in the plane and more on the ground, so such events are seldom given much consideration or attention.  They are just accepted as part of life's inevitable imperfections.

Of course, we all wish for our air travel to be as utterly safe as is possible, and when faced with the stark choice :  'Which would you prefer, to have your noise cancelling headphones on, and for the plane to crash and burn; or to take your noise cancelling headphones off and fly safely?' it seems an easy choice to make.

So, in an abundance of caution, the airlines have banned anything with transmitters in it from operating at any time on a plane, and all other electronics are banned when the plane is at low altitudes.

But, does this really make sense?  While it is true that interference with the plane's electronics may have more severe consequences at low altitude and speed, the electronics themselves are no more at risk in these stages of a flight.  So how is it that a plane can fly for hours at a time with a cabin full of electronics-using passengers and with no problems at all, but then, all of a sudden, we are told there is a risk to the plane's operational safety at lower altitude?

How real is the risk?  How great is the risk?

An Attempt to Measure the Risk

The answer to these questions can be seen from two perspectives.  The first answer is that the number of unexplained but potentially dangerous events in passenger planes while flying in a state with passengers allowed to use their electronics is exceedingly low.

We'll guess there might be one unexplained event per ten million flying hours - maybe even one event per one hundred million flying hours.  To put this into perspective, 10 million hours is the same as 1150 years, and obviously 100 million hours is therefore 11,500 years.  You could spend half your life on planes, and live to 80, and have only one chance in between 30 and 300 of ever being on a plane with an anomalous event, which will probably have a benign outcome anyway.

We calculate these numbers based on there being about 18,000 passenger jets in the world, and maybe another 10,000 prop planes - assume they all fly 8 hours/day, that is almost a quarter million flying hours a day for all passenger planes, or 82 million flying hours a year.  One hears apocryphally of puzzling incidents maybe a couple of times a year, maybe not.

And now the second part of the answer is that these are unexplained events.  No-one has been able to demonstrate that if you take, eg, your iPad and turn it on, the plane will immediately veer to the right.  Until a researcher can show a clear causality between something like this with an electronic device and a response by the plane, there is no valid reason to believe that an unexplained event is the result of interference from onboard electronics.

It is just as likely that it was a hardware 'event' within the plane's electronics - a leaky capacitor, a bad solder joint, a failing memory chip, a corrupted piece of data received along a wire - as it is an external interference.  It could even be interference from solar rays.  And let's not forget the possibility of buggy software - airplane operating systems are comparably complex to computer operating systems; and until such time as my Windows computer stops crashing (figuratively) I've no confidence at all in the ability of an airplane's operating system to also not crash (and potentially literally).

So, on the one hand, these mysterious glitches are very uncommon.  On the other hand, no-one knows what is causing them, and for sure there are very many other possible causes, as well as the possibility of interference from consumer electronics.

Other Non-Aviation Electronics Seem to have No Problems

Here's an empirical concept as well.  Chances are you often have other electronic devices resting on the top of your computer.  In my case, I sometimes have cell or regular phones, headsets, media players of all sorts, tablets, and all the other gadgets that surround me in my daily life directly on top of, or very close to, my computer.

I've never ever sensed any interference from those to my computer, even when they are inches away.  So why would an airplane's avionics, tens of feet away, and in shielded cages, be more at risk?

Are Airplane Avionics More Vulnerable to Interference

What is it about airplane electronics (avionics) that might make them more delicate, more susceptible to interference than normal home electronics?  Nothing!

In fact, avionics equipment is designed to work without problems even though they are probably plugged into an equipment rack with lots of other pieces of avionics all around them.  They are specially built to be resilient to interference from other nearby avionics devices.

Okay - that's a good thing to do.  But, if this is the case, why does this resilience only extend to the strong radio frequency (RF) leakages of nearby other high-power devices, but not also to the massively weaker RF signals possibly picked up from portable electronic devices way away in the passenger cabin?

If a device is shielded to reduce the leakage of interference it transmits, the same shielding also reduces the flow of interference from outside and into it.

It isn't as though an airplane is a radio frequency radiation free environment to start with.  A typical plane is full to overflowing with RF energy and electronic emitting sources, in the cockpit, in the engines and generators, in the pumps and sensors and hydraulics, in the in-flight entertainment systems, the thermostats and heaters, the galleys, the high powered communication radios and radars, and so on all the way through the plane - even to the smoke detectors in the toilets.

And how about the potential for interference between different avionics modules?  You have a collection of different semi-independent electronic boxes, all being plugged into racks of electronics in the plane?  Surely the devices side by side to each other are more at risk of cross interference than they are at risk of interference from devices tens of feet away?

Adding whatever infinitesimal extra RF emission from your iPad to this mix is like one voice struggling to be heard in a choir of a thousand voices.

We should also understand a thing about distance.  The plane's sensitive avionics equipment is right next to other avionics equipment, whereas your device is maybe even 100 ft away.  This is significant.

The effect or strength or energy of the radio emissions from most devices reduces on a cube basis.  That is, if you double the distance the two things are apart, the signal is diminished not two fold, not 2 x 2 = four fold, but 2 x 2 x 2 = eight fold.  If you increase the distance from eg one foot to ten feet apart, then the interference is reduced 10 x 10 x 10 = 1,000 times.  And from six inches to 50 ft, well, you've reduced the effect one million times.

An Excess of Ill-Informed Caution?

So it seems plain the airlines are being extraordinarily cautious at banning some electronics completely, and other electronic items selectively, in a situation where there has never been a proved link between the items restricted and their planes' electronics, and in a situation where there are other much more likely explanations to the occasional anomalous event that occurs with a plane's control systems.

Rather than get to the bottom of these occasionally mysterious events, they simply decide to inconvenience us, their passengers, 'just in case'.

And so we've seen a series of ridiculous Luddite like moves over the years, on the basis of 'better safe than sorry'.  I remember one time in the mid 1990s getting into an argument with Qantas; at the time they had a blanket ban forbidding one to use CD players at any time on their planes.  They agreed there was no reason to suspect CD players of interfering with their planes, but said their commitment to absolute uncompromising safety meant they refused to allow even the tiniest of risks to be present.

Of course, CD players are no longer banned, other than below 10,000 ft, and to suggest that a CD player might cause problems to the plane's avionics seems as ridiculous today as, in truth and reality, it also was 15 years ago.  CD players are the same as they were back then, and Qantas (and other airlines) have slowly come to realize that they are safe.

There are still lots of devices that are completely banned - for example GPS receivers and walkie talkies.

Does it Make Sense to Ban Anything on Planes

Which brings me to the final part of the article.  The underlying sense - or nonsense - of the remaining partial bans on items, either completely, all the time, or else selectively below 10,000 ft.

The bans are often overlooked, either on purpose or accidentally

These bans are very 'porous' in that many people ignore them, either deliberately or accidentally.  How many times have you forgotten to turn off your phone, or your Bluetooth headset?  And, when you have your Kindle or other eBook reader on, how many times has its Wi-Fi transceiver been active?  Or even the Wi-Fi transceiver in your laptop?  Chances are you never think to turn that off, even though the airlines ban any type of radio transmitter at any time.

There are also stories of people on planes who, after being instructed in the strictest possible terms to have all their electronics turned off, have then been listening to the pilot's announcement only to hear a phone start ringing in the background in the cockpit.  This is not just urban legend - I've had pilots tell me it has happened to them personally.

Some electronics are not banned

Indeed, why are we allowed to leave hearing aids on?  Why are we allowed to leave our digital watches on?  Or pacemakers and oxygen flow enhancers?

How is it that a digital watch is 'safe', but a digital eBook reader is 'dangerous'?  How is it that a hearing aid is 'safe' but noise cancelling headphones are 'dangerous'?

Why is the inflight entertainment system 'safe' but your personal video player 'dangerous'?

Why do we have to turn off 'anything with a power switch' but the airline doesn't have to turn everything of its own, on its plane, off too?

Not all airlines ban the same things

These days the airlines don't all uniformly have complete blanket bans on radio transmitters any more.  Many airlines now allow cell phones to be used in flight.

So they are willingly exposing their planes to the most 'scary/dangerous' of all electronic items - high powered digitally transmitting multi-frequency cell phones, that may be squirting out signals on half a dozen different frequencies simultaneously.  And many phones these days have built in GPS receivers too - another item otherwise completely banned.

So how is it that some planes, operated by some airlines, can safely allow some electronic items to be operated, whereas other airlines - flying the exact same planes - claim them to be too dangerous to ever be turned on?

Why do some airlines allow you to turn your cell phone on as soon as the plane has touched down, whereas others require you to wait until the plane has stopped at the gate?

Looking at the Problem from the Other Perspective

The problem, such as it is, is that on rare occasions, the electronics in a modern airplane will suddenly act unexpectedly.

We don't know what causes these unexpected and non-duplicable events to occur.  There are many possible explanations, ranging from bugs in the software that controls the equipment through to faulty components in the equipment itself.

The airlines have decided to share the blame generously with the portable electronics that we travel with, even though they have no certain scientific proof that our electronics might be causing these problems.

This lack of proof is understandable, because it is close to impossible to recreate these 'glitches' at will.

But - flip this last statement around.  Let's not focus on trying to prove that our electronics cause problems.  Let's instead prove they don't.

Surround any part of a plane that has given problems with a mix of all the typical electronic devices, all operating simultaneously, and see if the plane part functions normally or not.

If it does, then surely it is reasonable to infer that whatever the cause of its rare glitches, it is not anything to do with consumer electronics.

This doesn't tell us what causes the problem.  But it does tell us what doesn't cause the problem, and surely that is significant and valuable.

There is another explanation for the possible increase in unexplained glitches.  Maybe these events are not due to the increase of consumer electronic devices on planes.  Rather they may be due to the changing nature of airplane control systems.  What used to be operated by wires and pulleys have become computer controlled systems, with increasingly complex and sophisticated computers controlling them.

Could the problems be due to the airplane's own control computers, rather than due to your iPod?  Could they?

What do you think?

 

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Originally published 13 May 2011, last update 02 Jul 2017

You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me as original writer.

 
 
 
 

 


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