
Fliers Must Turn Off Devices, but It’s Not Clear Why - taylorbuley
http://bits.blogs.nytimes.com/2011/11/27/disruptions-fliers-must-turn-off-devices-but-its-not-clear-why/
======
Bud
There is actually a very logical, sensible reason to have everyone power off
and stow their devices during takeoff and landing, and this story
disappointingly failed to cover it:

By far the most likely time for any accidents or incidents to occur is during
takeoffs and landings. If everyone has 15 objects out and is busily typing
away, it's going to be tht much more difficult for flight attendants to get
everyone's attention to give instructions, and crucially, much much more
difficult to evacuate the plane as quickly as possible.

This isn't controversial, complex or even hard to figure out. It's the same
reason they aren't serving food and drinks at those times, and the same reason
you have to stow your carry-ons and put your tray tables up at these times.

Disappointing that the Times did not bother to learn this or to write a more
informative story.

~~~
ramanujan
The FAA/TSA alway justify things in terms of "safety" and "security", but
never calculate the massive costs associated with seizing billions in
toiletries and productivity.

Let's calculate that. There are about 800 million[0] passengers on domestic
and foreign owned airlines in the US market, with many people flying more than
once per year.

Each person is taxed between 1-2 hours in terms of "safety" regulations,
ranging from backscatter scans to nail clipper seizures to water bottle
appropriations. Once on the plane, they are again taxed by about 15-30 minutes
on each end from the ban on use of laptops, including the emergency landing
song-and-dance that the vast majority[1] of passengers have already seen.

So let's say conservatively about 2 hours in total. So 1.6 billion hours per
year. At a conservative estimate of $10 per hour, that's $16 billion per year.
This does not include the $8.1 billion wasted on the TSA itself.

[0] [http://www.usatoday.com/travel/flights/2010-03-29-airline-
pa...](http://www.usatoday.com/travel/flights/2010-03-29-airline-passengers-
revenue-decline_N.htm)

[1] In the unusual circumstance that a first time flyer is on board, a video
could instead be played during check-in online, in the lounge, or on the seat
back rather than slowing everyone down to look at the flight attendant. Would
not be surprised if the percentage of first-time flyers on US domestic flights
is less than 5%.

~~~
city41
I don't understand how planes are seizing productivity when the nearest
competitor -- an illegally driven car -- is about 5 times slower. Yes they
have quite a bit of overhead during take off, landing, baggage claim, driving
to the airport, security screening, etc. But what else can reduce a trip's
time from days to hours? The amount of time wasted in that overhead compared
to the time gained is minuscule.

~~~
ams6110
Unless you are going a long way, it may well be faster to drive. For me: 1
hour drive to the airport, 1+ hours at the airport for check-in, security,
etc, 1 hour at destination to retrieve baggage, get a rental car, and get out
of the airport... plus the time of the flight. If I can drive in under 6
hours, I'll seriously consider doing that rather than deal with all the hassle
of air travel.

~~~
fosk
Except that if you drive for 6 hours, you can't talk on the phone and you
can't use your laptop. Your point doesn't make sense to me: if you're willing
to drive for 6 hours, you're also willing to stop working during all that
time, while if you flight you'll always find some time to work, at the
terminal or in the plane.

~~~
bad_user
If driving you can talk on the phone for the whole 6 hours. I did something
similar at least once.

Also, the driver can't use a laptop, but because of the driving activity
itself, the driver is not so easily bored. Boredom is the main reason why I
power on my laptop on a plane. Also, the other passengers can easily work on a
laptop, watch a movie and so on. If you've got a 3G connection, the passengers
can also go online - even I as the driven, I often find myself checking my
emails while driving, plus I'm connected on Skype for the whole ride. The only
problem here may be the comfort of your car, as you'll have problems having a
laptop in your lap if the car is a small one. I also never get anything done
on a plane when trying to work, especially because I don't have Internet
connectivity, so I would rather listen to Podcasts or read a book and when
driving Audio books are great btw.

So, related to comfort, I always prefer a couple of hours in my 10-year old
Audi A6 over a plane ride. If the car ride is longer than some threshold, like
the mentioned 6 hours, I do agree that a plane ride is better.

~~~
viraptor
> even I as the driven, I often find myself checking my emails while driving

Why would you ever do that? If you don't care about your safety, at least make
sure you're less likely to kill others, please...

~~~
bad_user
Oh, cut the drama. I use text 2 speech.

~~~
viraptor
I guess that even for short messages rather than interaction, some of this
applies: <http://www.psych.utah.edu/AppliedCognitionLab/cdir489.pdf>

------
gchucky
MythBusters covered this awhile back, and busted the myth: "The final
explanation is that, even though the airplanes appear to be well-shielded
against cellphone interference, there are so many different electronics in a
cockpit, as well as so many different cellphones constantly coming out, the
FAA doesn't want to do the necessary testing."[1]

[1]
[http://kwc.org/mythbusters/2006/04/episode_49_cellphones_on_...](http://kwc.org/mythbusters/2006/04/episode_49_cellphones_on_plane.html)

~~~
FaceKicker
If they actually aren't willing to test whether cell phones interfere with
their equipment, they shouldn't be allowing cell phones on the plane at all.
Relying on people's compliance (or even just their attention) to ensure the
plane doesn't explode is absurd.

~~~
bdonlan
There are other options than "allow free cell phone use" and "frisk all
passengers to ensure they're not smuggling in an active cell phone". Asking
passengers not to use them is a decent compromise between safety and
inconvenience. Naturally, if a crash were to actually occur due to mobile
phone use, the FAA would need to revisit this guideline.

Note that GSM phones in particular _do_ interfere with radio systems - that
irritating buzz you hear when a GSM phone is near a speaker amplifier can
affect airplane systems as well (although it depends on where the phone is on
the plane, of course). There can also be interference with _ground_ systems -
cell networks aren't designed to deal with the rapid tower transfers caused by
ultra-high-altitude phones moving at Mach 0.85.

~~~
pyre

      > cell networks aren't designed to deal with the rapid
      > tower transfers
    

I always see this argument brought up (on HN), but what does the FAA care
about cell carriers' networks? Why don't they ever use this justification when
asked to justify their policy?

~~~
dfox
They don't use this justification exactly because they mostly don't care about
that. It's interesting that there probably is no regulation that forbids usage
of cell phones at high speeds and high altitudes (as opposed to "on board of a
plane"). At least ETSI specifications seems to imply that it's perfectly legal
to operate whole GSM network on board of plane, while hinting at fact that
direct communication with basestation on ground from plane is not intended
mode of operation and probably will not work. On the other hand there seems to
be an large amount of anecdotal evidence, that it really does work, although
with marginal call quality.

So conclusion might be something along the lines of "it's not designed to do
that", which seems like pretty good justification when you are talking about
airplane safety.

~~~
pyre

      > So conclusion might be something along the lines of
      > "it's not designed to do that", which seems like
      > pretty good justification when you are talking about
      > airplane safety.
    

I'm not sure the reasoning follows:

1\. "it's not designed to do that" refers to cell-to-ground communication,
nothing to do with the safety of the plane.

2\. cell-to-ground communications issues only apply to cellphones, but the FAA
policy applies to _all_ electronics.

~~~
dfox
I intended the second paragraph as my though on why telecommunications related
organizations don't exactly discuss whether cellphones works on board of a
plane and this intention was then probably lost by inserting that paragraph
break :)

FAA's and related regulations are probably motivated by fact that it's
essentially impossible to test that aircraft's systems work as intended even
in presence of random consumer devices on board. EMC issues can be caused by
almost any electronic device not only devices containing radio transmitters
(eg. EU regulations require EMC certification for anything that, possibly
internally, produces or uses signals >=1kHz).

------
trout
The wikipedia article is more interesting:
<http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft>

This sums it up pretty well: "The regulatory agencies and aviation industry
take the position that any increased risk is unacceptable if it is avoidable."

There's some technical channel sharing problems where phones have access to
more towers than designed on land. The FCC can't predict what would happen if
phones were allowed to stay on in regards to cell roaming. They also don't
know the effects on the avionics.

It looks like they're developing 'picocells' to have an on-board tower, but
there are struggles with the different cellular bands. Though, there are some
European carriers that have been successful with just letting people keep
their phones on.

That said - I think if your device doesn't have a radio on it, it should be
allowed to stay on. Which probably won't fly given the 'if it's avoidable'
rationale.

~~~
Steko
They just dont want to say it's ok then get sued to hell whenever a plane goes
down.

------
noonespecial
The last time I flew, most of the people around me didn't know the difference
between "airplane mode", "standby", and "off". I'd bet that at least 80% of
the phones on that flight were full on despite the efforts of the crew and the
device's owners.

Everyone turning off everything successfully before takeoff is pure fiction.

~~~
bdonlan
Cell phone transmissions are much less frequent when the phone is idle than
when it is in active use. Even if people just stop talking on the phones, it's
better than nothing.

~~~
tommi
True. But I bet a phone on the airplane idle is more active than on the ground
idle due to network searching.

------
ghshephard
Easily the most annoying part of flying for me, particularly when doing a
quick flight from SFO to LAX is the insistence that I turn off my Kindle while
we are lining up for the runway.

* People reading newspapers, and books - both of which are larger, heavier, and just as distracting, and in the case of newspapers, a greater obstacle - are not told to put away their reading material - so the argument that "people need to pay attention on takeoff/landing" is not consistent.

* RF engineers haven't been able to prove that a kindle in airplane mode has a negligible likelihood of impacting the flight systems of an airplane. Really?

One solution, albeit a slightly annoying one, is to have a distinctively
colored LED or indicator that is visible from the walkway of the airplane to a
stewardess, but not annoying to the reader, which indicates whether a device
has been placed in airplane mode.

The new motto then would be "Everyone please place their FAA certified
equipment into airplane safety mode. All other electronics, iPads, kindles,
laptops, gameboys, iPhones, iPods, must now be put away"

People, being people, would likely start putting the fake LEDs on their
electronics to simulate the FAA approved one, unfortunately, not sure what to
do about that.

~~~
MatthewPhillips
How do we know there isn't a bug in a device's airplane mode?

~~~
mikeash
How do we know there isn't a bug in a device's off switch? Most of them are
software-based these days.

~~~
MatthewPhillips
Most of them allow you to take the battery out if it comes to that.

~~~
mikeash
But nobody actually does, so clearly we're content to trust the software on
that matter.

~~~
MatthewPhillips
They do if the power button malfunctions. Are you aware of any devices that
cannot be turned off because of a software error?

~~~
pavel_lishin
nknight mentioned iphones, ipads, and unibody macbooks.

------
brk
Yes, absolutely turn off all devices. We know with certainty that ANY
transmitter can cause terrible havoc with the plane's electronics.

Unless you're paying the ripoff $10 fee for in-flight Wifi, then the dangers
are magically avoided.

~~~
bdonlan
There's a big difference in power levels between wifi (that only has to go a
few hundred feet to the on-plane transceiver) and cell phone radio (that has
to go possibly several miles to a ground tower). Additionally, GSM has a
transmission pattern that can cause noise in radio receivers and other audio
devices - just try holding an active GSM phone up against a poorly shielded
speaker sometime!

~~~
brk
I know all this. I also know that people will forget to turn their phones off,
will have phones and laptops and all manner of devices in checked luggage that
are possibly left on, and that these signals are all around the plane anyway.

If there were any credible threat from leaving your phone on, or having it
actively transmitting, then ALL phones would be outright banned from the
plane. Otherwise, a group of terrorists could take down a plane simply by
passively not turning their phones off? When you look at all of the other TSA
security theater bullshit, it's a safe conclusion (IMO) that the RF from your
phone will not interfere with the operation of the plane, based on the simple
fact that they are not banned in the first place.

Not to mention, I think that if this were even a moderate concern it would be
easy to equip the flight attendants with an RF monitoring device they could
walk down the aisle with and detect close-proximity transmitters from cell
phones.

On modern flights where coach seats have been spaced at the minimum allowable
level and people are forced to bring everything as carry on to avoid bagge
fees you see far more safety threats from under-seat luggage sticking out into
the seating aisle, potentially inhibiting safe exit of the plane in an actual
emergency.

~~~
gnaffle
Lithium Ion batteries are allowed on planes as well. Is this conclusive proof
that they can't damage the plane if they catch on fire?

All decisions are trade-offs, banning laptops and cellphones today would
probably bankrupt the airlines since nobody would fly. Likewise, non-critical
computer systems in an airplane have less stringent certification standards
than critical systems (it's OK for the electronic flight bag laptop to
occasionally crash if you keep a stack of paper charts in the cockpit).

It's not like a plane is likely to just go down because of interference, but
instruments acting will certainly increase the workload of pilots, making an
accident more likely. Likewise, people shining lasers at airplanes tell
themselves that this is OK, surely the pilots can deal with a little light
disturbing their night vision? They don't appreciate that the pilots already
have a high workload during landing.

The wikipedia article
(<http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft>) has a link to a
NASA study of interference events showing that they can in fact happen
(although not often). Of course, you can still claim that these pilots are
making stuff up or that this is another NASA conspiracy, but it's actually
possible to read up on the subject instead of just offering wild theories and
speculations based on your own opinion and wishes.

------
mhb
IEEE - Unsafe At Any Airspeed: Cellphones and other electronics are more of a
risk than you think:

[http://spectrum.ieee.org/aerospace/aviation/unsafe-at-any-
ai...](http://spectrum.ieee.org/aerospace/aviation/unsafe-at-any-airspeed/0)

~~~
dmarquis
The method used in that article is just counting flight incidents in some
historical data that may possibly have been caused by interference. The
evidence that consumer electronics are the cause is just anecdotal:

"In one telling incident, a flight crew stated that a 30-degree navigation
error was immediately corrected after a passenger turned off a DVD player and
that the error reoccurred when the curious crew asked the passenger to switch
the player on again."

~~~
politician
After a 30-degree navigation error was corrected by turning off a DVD player,
would the pilot seriously endanger the aircraft by asking the passenger to
turn it on again to test? Anecdotal, and probably completely false.

~~~
ceejayoz
> After a 30-degree navigation error was corrected by turning off a DVD
> player, would the pilot seriously endanger the aircraft by asking the
> passenger to turn it on again to test?

No?

1\. It was already demonstrated that turning it off fixed it. If you see the
instruments goof up again, you tell the guy to turn the player back off.

2\. Pilots are extensively trained to deal with equipment failures, including
total loss of power and instruments.

~~~
politician
I don't buy it. Ostensibly, this is a commercial flight where lives are at
stake, so I strongly doubt that absent FAA direction the pilot requested this
test.

 _It was already demonstrated that turning it off fixed it. If you see the
instruments goof up again, you tell the guy to turn the player back off._

It's unclear from the account whether this was an instrument error or an
actual flight path deviation. The latter being a more serious and
unpredictable error. Who in their right mind would want to repro this given
the unknowns?

 _Pilots are extensively trained to deal with equipment failures, including
total loss of power and instruments._

Pilots also operate in an environment of substantial regulation where I'm sure
a policy exists for investigation of operational interference. I suspect this
policy is in line with the FAA's stance that "avoidable interference is
unacceptable" and certainly this incident describes an avoidable interference.

I don't see any reason to retract my position that this story is likely a
myth.

EDIT: My position depends on a number of assumptions that may be faulty: that
this incident took place in the USA, within the last decade, on a plane
operated by a significant carrier.

~~~
ceejayoz
You can feel the story is a myth, but it remains hard to argue that it'd
"seriously endanger the aircraft" by doing what was described in the story.

------
knightgj
I recall years ago sitting in the LAX UA red carpet club listening to a
portable cd player (yup, long ago). My music cut out, and thru my cd player,
that didn't even have a radio as I recall, I was listening to the pilot
pulling into the gate outside the window communicating with the ground crews
over his headset.

Now, as I understand it, that lovely FCC stamp on the back of our electronics
means the device must accept any interference received since it's a consumer
product... but I'd also hate for my pilots to unexpectedly get my co-
passenger's latest dubstep mix opposed to the air traffic controller during
takeoff.

For the record: I'm the guy that intentionally leaves his phone on, in
airplane mode, idling. I think this is good enough.

------
dfox
There are two sides to this:

EMC is black magic and airplane safety is another and thus nobody is willing
to say that using random RF devices onboard of plane is safe - for one reason
it's almost impossible to test. By the way owner's manual for my new car
contains paragraph that explicitly disallows usage of any RF transmitter
inside the car that does not have external antenna (and I would assume that
most car manufacturers include similar paragraph in their manuals and also
that everybody ignores them).

Cellular networks and cell phones are not designed for relative speeds and RF
propagation modes of high flying commercial aircraft. Most access methods of
digital wireless networks depend on precise timing where propagation delays
are significant and thus need to compensate for relative movement of phone and
base station and there are pretty low limits of how fast movement can be
compensated (it's almost practical to drive car faster than speed limit of
GSM1800). Also higher levels of cellular protocol stacks are not exactly
prepared for situation when phone sees large number of accessible cells with
quite strong signal and this set changes very quickly.

------
swdunlop
There is zero risk to a regulator in maintaining a pointless yet harmless
regulation. There is nonzero risk to a regulator in revoking a regulation that
may be blamed in the future by a crash investigator.

Even if the risk is absolutely 0.0001% -- fear and CYA wins. Our system of
regulation and collective transfer of responsibility to regulators ensures
that like a federal subsidy, nonsensical regulations are forever.

------
arn
Here's what I don't understand, and admittedly I have very little knowledge of
the industry.

There seems to be some sort of approval process for electronics to be vetted
during takeoff and landing. Several in-chair entertainment systems seem to
have this rating/designation and are allowed during takeoff/landing.

So, is there no dollar amount that could be paid to properly test a particular
product? Let's say the Kindle or iPod. It may be millions of dollars, but
wouldn't there be a huge word-of-mouth and marketing upside if you could get
approved for such a thing?

~~~
lucasjung
I currently work in developmental flight test. Any time we add a new piece of
electronics to an aircraft (or replace an existing piece with a new version),
be it a radio, a computer, or test instrumentation, we have to conduct an
Electromagnetic Compatibility (EMC) Safety of Flight Test (SOFT) to make sure
that the new equipment does not interfere in any way with avionics that are
critical to safety of flight. Even if it's something that's not being
installed per se (e.g. a laptop for collecting test data), it has to be
tested. Sometimes there are exceptions, such as very minor upgrades,
especially minor software updates.

Generally everything is designed so as to not interfere, but every once in a
while something causes unexpected interference. Sometimes it's because the
designers screwed up, sometimes it's because a bespoke item wasn't
manufactured to the correct spec, and sometimes it's because of something
nobody anticipated.

The problem with consumer electronics is that they haven't gone through this
process. None of them _should_ cause interference, but we can't be sure
because they were never subjected to comprehensive EMC SOFT. Nor would it
really make sense to spend that kind of time and money when we can just
mitigate the risk of interference by having everyone turn everything off
during critical phases of flight.

~~~
RandallBrown
but wouldn't it make sense for Apple to pay to do the testing? Being able to
say "The iPhone is the only phone you can use during your whole flight" would
be worth quite a bit of money to them.

~~~
lucasjung
They would have to test every model of iphone against not only every model of
commercial airliner in operation in the U.S. (including puddle-jumpers), but
against every major variation in avionics suite among each model. This testing
is not cheap. Even for Apple, it would be prohibitively expensive.

~~~
ghshephard
There's probably only 80 different commercial airplane models. This testing
probably costs around $1000/hr - figure 5 days testing @ 8 hours a day = 3200
hours = 3.2 million dollars. Seems to be a reasonable price to pay.

~~~
lucasjung
As I said, it's not just the different models, it's the different avionics
suites within each model (e.g. two aircraft of the same model might have
different radios or different navigation equipment, etc.). For each plane, you
would need a few hours of testing, which probably costs more than $1000/hour:
you have to pay for the plane, the crew (who have to be qualified to perform
this type of testing), the ground support equipment, maintenance support, and
any fuel burned during testing (e.g. running the APU to provide power during
testing will consume a small but not insignificant quantity of fuel).

EDIT: Almost forgot: After the testing is complete, you have to pay to have a
test report written up and published, and then you have to pay for the FAA
certification process. Probably not cheap.

~~~
Terretta
The US Treasury has less cash on hand than Apple. Apple makes prepayments of a
billion dollars for parts. The numbers you're tossing around are, in context,
very cheap.

~~~
lucasjung
Apple only pays for things that they expect good ROI for. I doubt very highly
if they would recoup the money spent to get their phones FAA-certified, let
alone the opportunity costs compared to spending that money on something else.

------
ShabbyDoo
Let's presume for a moment that some sort of interference which could be
generated by a box the size of a laptop might have a non-trivial risk to
passenger safety. Now, think as a terrorist might. How about sending your
minions onto planes with devices which look like standard consumer electronics
devices but are capable of generating high levels of interference? Around the
holidays in the US, someone checking or carrying on what appears to be an A/V
receiver in a box would not raise suspicion -- just a gift for a relative.
Now, inside that "receiver" is a battery and a transmitter (I'm not an
electrical engineering sort of guy, so substitute the appropriate components)
which emits what signals the terrorists hope will interfere with onboard
avionics. Via a remote switch, the terrorist turns on the device during take-
off and landing. If the plane crashes, is forced to make multiple attempts at
a landing, etc., then the terrorists know they're onto something. They will
refine their techniques until they can make plans fall out of the sky. If not,
they try other experiments -- different frequencies, etc. Could such
experiments even be carried out through transmitters on vans which could be
temporarily parked on highways near airports? What if the terrorists could
purchase airplane components with which to conduct their own testing and
refine their "weapons"? Surely such an avenue of attack, if feasible, would be
less effort than training your minions to fly an airplane, even if learning to
land was not required? That no known terrorist attacks via this vector have
been reported suggests it implausible. A problem with most terrorism
"experiments" is that, if the experiment fails, the experimenter ends up
imprisoned and thus incapable of further experimentation. Given the obvious
recruiting issues the likely outcomes of either imprisonment or death present,
terrorists ought to take like ducks to water toward techniques which allow
repeated experimentation and refinement. That no incidents have been reported
due to avionics malfunction suggests the near impossibility of actual
passenger risk. QED?

~~~
marshray
No. There's still a human pilot flying the plane. Even an arc welder
(probably) won't magically make it go in to a nosedive.

What could happen however is that certain navigation systems become unreliable
during landing. Add that to bad weather, bad information, human error, and bad
luck and you have a potential disaster.

But it doesn't seem likely that a terrorist would find such a plan worthwhile
to pursue. After all, they want to be the star of the show right? Would they
martyr themselves so some pilot gets the blame for landing on the wrong runway
during a thunderstorm?

~~~
ShabbyDoo
Hmmm.....could the terrorists cryptographically encode their flight schedules
along with techniques, drop the encoded versions on public repositories, and
distribute the keys to the media upon successfully killing people? This way,
they could prove their involvement.

Your point about the compound nature of risk is valid, but doesn't it also
suggest that the actual risk of allowing electronics during takeoff/landing is
quite low as well?

~~~
marshray
The thing that 'accidents' has in its favor over 'terrorist' is volume. Many
thousands of takeoffs and landings and millions of passengers with electronic
devices _every day_. Even a small additional risk is guaranteed to line up
with the right mix of other factors occasionally.

Terrorist attacks in the US are extremely rare, and they typically expend
their resources with each attempt so they want a high probability of success.
There are far better avenues for a technically sophisticated attacker these
days than getting on a plane and emitting harmful radiofrequency interference
in excess of FCC guidelines.

> drop the encoded versions on public repositories, and distribute the keys to
> the media upon successfully killing people

I'm far from an expert on the mindset of terrorists, but I really don't think
that's going to check the box for those aspiring to martyrdom.

Edit: It's an interesting thought experiment though. Let's say the next time
an Air France crashes mysteriously into the ocean, the next day some group
sends a private key to the media which decrypts a file from Google Cache
containing the flight number and their religious slogan of choice. How would
the media around the world report that?

A "hoax terrorist" could also encrypt and upload files for _all_ the flight
numbers, or perhaps have a smaller set of files that decrypt differently with
different keys. If they used CBC mode, they could even choose part of the
plaintext when they disclosed the IV. You'd have to trust a cryptographer to
know how reliable of an indicator that actually is.

Or a counter-hoax-terrorist could do that to discredit you. Would kinda suck
to martyr yourself and have no one believe you about it later. If the CIA were
smart, they would be doing just that, in advance.

------
1010011010
I think part of it is that the flight staff want you to pay attention during
takeoff and landing. Having your headphones on/in means you're not listening
to them.

Another part is that the flight staff wants fewer things potentially flying
around the cabin if there's trouble. of course, they don't usually ask you to
put away books...

Cell phone companies want you to turn off your phones because they mess with
the ground towers. Flying past towers rapidly puts load on the cell network to
transfer your phone's connection between towers rapidly. Your phone can also
see more towers than usual, causing it to possibly flap between them in
unexpected ways.

The bit about it being unsafe due to messing with the plane's avionics is
total bunk, though. I never turn off electronics on flights, except to save
battery.

------
orthecreedence
For me it's great. The last thing I want is to hear someone's boisterous 4
hour conversation with an excited family member while I'm sandwiched between
said conversationalist and some 300-pound whale who keeps leaning on me as
(s)he repeatedly drifts in and out of consciousness.

Everyone's phone plays movies now anyway. Isn't that good enough? Do we really
have to be plugged in every second of the day? Americans are too spoiled. OMG
I can't jabber on my phone while flying? waa waaa ='[

------
estevez
What are the consequences for simply refusing to obey a crew member's
instruction to power down your Kindle? Sort of like willfully ignoring the
distinction between the first-class and economy security lines---something I
wish more people would do.

~~~
tobtoh
If you are getting ready for take-off, the plane returns to the gate and you
are escorted off the flight and charged with compromising airline safety and
ignoring a steward's order. This happened to a guy two rows in front of me on
an American Airlines flight a couple of years ago. He twice refused to turn
off his mobile phone as we were taxiing towards the runway.

~~~
shinratdr
Why not just lie? You genuinely are making the attendant's job harder by
telling them point blank that you refuse to comply with the order they have to
give to you to take off. It's much easier for everyone if you just act like
you turned it off.

~~~
tobtoh
This particular guy was in the middle of a conversation on the phone :)

------
tlrobinson
I was on a flight a few months ago where we stopped on the runway for a few
minutes and the flight attendants told us we couldn't take off because "too
many" devices were still powered on.

They also told us they had to "reboot Windows".

I'm pretty sure they were full of shit.

~~~
raldi
What airline?

------
dev_jim
I haven't turned off a cell phone while flying for almost ten years now. I
refuse to be part of any safety or security charade.

~~~
BonesLF
Almost there with you. Charade is useful if it prevents a confrontation with
someone who does not understand the security theater.

Thus, I turn the screen off for the 3 seconds it takes the flight attendant to
walk by. I've been doing this for years. A fair compromise? Silly, but
effective perhaps.

~~~
Osiris
I turn off my cell phone simply to save the battery power. You don't get any
signal above a few thousand feet, so why not save on battery for the next few
hours? Heck, sometimes I even use my laptop's USB to charge the phone in-
flight so it's full when I land.

I think the dumbest thing is having to turn off a Kindle. Is that even
possible? Pushing the power button just goes to screensaver which uses exactly
as much power as when you're actually using it.

~~~
lucasjung
> _I think the dumbest thing is having to turn off a Kindle. Is that even
> possible? Pushing the power button just goes to screensaver which uses
> exactly as much power as when you're actually using it._

You can turn a kindle off by holding the power switch for a few seconds. I do
this every time I fly, for both takeoff and landing (I leave the wireless off
for the entire flight). Given how low-power a kindle is, I find it highly
unlikely that it could cause interference (unless you leave the wireless on,
which could definitely cause interference), but I've seen enough surprising
results from Electromagnetic Compatibility (EMC) Safety of Flight Tests (SOFT)
to know that you just can't make assumptions about stuff like that.

------
zeteo
If airplanes were vulnerable to radio frequencies, then terrorists have no
need to acquire SAMs. A nice powerful amateur radio should do much better.

~~~
cperciva
Avionics systems are better shielded against _external_ interference than they
are against _internal_ interference.

~~~
zeteo
Based on how Faraday cages work, I don't see how that's possible. Do you have
a technical explanation or did you just pull that out of thin air?

~~~
cperciva
Planes (well, most of them at least) have metal skins. The avionics -- and the
passengers -- are inside this skin.

~~~
zeteo
Well, you can easily see that the plane's skin is not a Faraday cage since you
_can_ make cell phone calls, use your GPS etc.

~~~
cperciva
It doesn't provide complete shielding, no. But it does provide _some_
shielding.

------
mmaunder
There were 769.6 Million passengers carried in 2009 in the USA (domestic and
international). If each loses 30 mins of productive time on a plane because
they can't use e-books or devices below 10,000 ft, that's 384,800,000 hours
per year lost. Not everyone is working or learning something on a plane, but
it puts things into perspective.

[http://www.bts.gov/press_releases/2010/bts015_10/html/bts015...](http://www.bts.gov/press_releases/2010/bts015_10/html/bts015_10.html)

~~~
ShabbyDoo
I have used this sort of reasoning when arguing against low speed limits
implemented in the name of safety. Surely, for each 10 MPH decrease in highway
speed limits, we will observe a decrease in the number of deaths per year?
Presuming both this fact and the presumed political validity of speed limit
reduction to decrease death rates, shouldn't our vehicles be limited to
walking speeds? The reality is that most people implicitly choose an overall
level of risk in their lives and optimize the apportionment of that risk among
activities in a way which maximizes their happiness. If it took me four hours
to commute to work because I drove 10 MPH to be "safe", I could either spend
less time with my family or move my family closer to the office. Would my
children end up successful in life if they rarely saw me? The end game of
everyone moving closer to the office might be little specs on the globe of
uber density -- an unhappy way of life for most. How about subsisting on
ration kits (like those currently sold to doomsayers) as a way of minimizing
the horrific risks associated with un-necessary trips to the grocery store?
Obviously, people have some threshold of risk at which they choose expected
quality of life over expected quantity. Airplane travel, either with or
without restrictions on "portable electronic devices" can be evaluated
similarly. And, given Americans' propensity to drive places at high speeds,
shouldn't they be equally willing to incur what seems to be a trivial risk in
order to have more productive time?

~~~
tomkarlo
"The reality is that most people implicitly choose an overall level of risk in
their lives and optimize the apportionment of that risk among activities in a
way which maximizes their happiness."

Do you have anything to support this? Most economic theories say that people
make tradeoffs of time and money, but not risk. Risk is generally too nebulous
a concept for an individual to make any kind of rational decisions about its
allocation - we have no real concept of the risk we're incurring when driving
a car or stepping on a plane (and generally, our gut feeling is wrong.)

------
Goladus
While I don't think the title and point of the article is exactly _wrong_ , it
doesn't fairly consider the potential difference between one or two people
failing to power down their devices and several hundred people using multiple
devices.

Walking across a floor that is a cluttered mess, you might have a small chance
of tripping. Cleaning up most of the mess might reduce the risk to negligible,
even if you don't get _everything_.

That's the angle I would have liked to understand better.

------
packetwerks
In 1999 I was on a flight and sat next to an EE who worked for Boeing on
commercial airliners. He said that there was virtually no chance that a cell
phone would cause any interference. He said that as far as he could tell the
FAA rules stemmed from the FCC that stemmed from the cell carries pressuring
the FCC not to allow it. The reason he suggested was that cell phones at
altitude have line-of-sight to dozens of cell towers. As airplanes full of
cell phones fly through the air they associate and disassociate with cell
towers very quickly. The towers have to switch the handsets from tower to
tower more quickly than usual causing a lot of network traffic signaling
overhead between cell sites. Here's a wikipedia article on this
[http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft#Cell_...](http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft#Cell_tower_channel_re-
use)

Edit: added URL

------
lbrdn
Relying on passengers to turn off their phones seems like the most ineffective
approach no matter your desired outcome. Isn't it possible to insulate the
cabin to prevent RF from exiting? This feels simplistic, but other than that
is there a reason this wouldn't work?

------
law_of_poe
> 712 million passengers flew within the United States in 2010. Let’s assume
> that just 0.01 percent of those passengers...

> That would mean seven million people on 11 million flights endangered the
> lives of their fellow passengers.

0.01% of 712M is 71200. </pedantic>

~~~
Periodic
It looks like the writer meant either 0.01 or 1%, as all the other numbers
work out to one one-hundredth. It is a common math mistake to mix the decimal
representation and the percentile one. The same thing happens occasionally
when people mix cents and fractions of a dollar.

I was immediately suspicious when it was implied that a 737 can hold 20,000
passengers.

------
delinka
Fear.

Put your cellphone near your FM radio. Listen in amazement as the digital
chatter between your phone and some remote tower causes interference in your
radio reception and affects your listening pleasure. Now imagine that same
thing happening to the digital signals in the airplane's electronics while
attempting to operate the craft. Catastrophe, chaos, etc. ad nauseum.

Realistic? Doubtful for many reasons. But that's the fear the bureaucrats,
pilots, and passengers possess.

------
rabidonrails
Surprised the author doesn't bring up
<http://en.wikipedia.org/wiki/Crossair_Flight_498>.

------
stef25
A good friend of mine pilots commercial airlines and I asked her we're forced
to turn off devices, she says it's cause cell phones can interfere in the same
way as they do with music equipment. If one rings close to a loud speaker you
get that tell-tale electronic ticking sound and she says that can make pilots
not understand what air traffic control is saying … Not sure if this is true
or if she'd actually experienced it before.

------
rms
It's also only in the USA that airlines are so insistent about the lack of
electronics. On Asian domestic airlines, you get the same speech to turn them
off, but then the flight attendants will just ignore you while you listen to
your MP3 player during take-off. Asian domestic airlines don't fall out of the
sky _that_ much more often than American ones.

------
wazoox
I remember an article I've read around 1983 when this regulation was first
introduced. Some plane taking off suffered from instrument interferences at
take off, and trouble ceased when they asked some guy to turn off his "Game &
Watch". Though they tried hard to reproduce the problem, they couldn't, but
the rule nonetheless applies "just in case".

------
Tichy
Next up in the app store: "Terror" - the app that crashes your jumbo jet. This
app creates a magic pattern of radio waves that has a 84% chance of crashing
the plane you are currently on.

If you plan to use this app for actual terror, be advised to buy an Android
phone and not an iPhone, because there is no way this app will be accepted
into the Apple app store.

------
keithg
My college roommate was a pilot, and his explanation was that _on occasion_
some devices can cause static or interference on the pilot's headsets. Since
communication with the tower is critical during takeoff & landing, the policy
of power-off is in effect. I guess it's not as critical during taxi, since
that is allowed.

------
inopinatus
It was pointed out to me, years ago, that this is an FCC regulation not an FAA
regulation, the reason given being that cellphones in the air can/do lock onto
many more towers than on the ground (due to the inverse square law), and the
network control protocols & software are (or were) not robust against this.

------
adrinavarro
If someone has flown on a light plane with analog instruments they've noticed
that there's no reason to turn off your mobile (but keep it in your pocket
when we're taking off please).

Yet, a B737 or an A320 is a much more complex plane. For instance, it has a
lot of different electronic systems, ranging from the displays to the
multiple, backed-up computers that enable flight controls (manual flight) and
manage auto-pilot inputs.

I've seen a CRJ-200's first officer's (copilot) flight PFD and ND gone black
and reboot because someone in the back was trying to call home, without much
success.

The thing is, that never happened to my friend pilot before even with
passengers trying to call. And the power output of a phone trying to call
without much coverage isn't the same as the power needed in the center of a
big city (and at 8000ft, inside a huge metal tube, the cell reception isn't
great).

That's one of the main reasons. Granted it shouldn't happen and plane
manufacturers do test against these kind of things. And really important
systems, like backup instruments (standby) or flight computers are hardly
going to be affected by any kind of interference, so, no, the plane isn't just
going to drop from the sky. Yet an automatic A/P disconnection on long final
on the PF's (pilot flying) PFD and ND displays going nuts is something
serious.

And on the side of that, you don't want people having unknown electronic
devices sending signals when pilots have to be more focused (take off and
landing) and you better have them keeping an eye outside (or at their
newspaper, but you can't help that). That's pretty much the same reason why
they ask you to have everything stowed and leave your window 'opened' (you can
see if there's something wrong outside, like fire, and report it) during
takeoff and landing.

------
devs1010
The flight I was on last week mentioned they had some sort of sensor that
picked up 8 devices that were still on, and they waited for everyone to turn
them off before taking off, so I think they do know if people "forget" to turn
them off.

~~~
r00fus
Well, my wife always forgets to airplane-mode or turn off her phone on
flights... and takeoff/landing makes her crabby so I've given up trying to
remind her (esp. when there are no negative personal consequences after a
dozen of such instances).

I'm sure she's not the only one.

------
zimbatm
If shutting down the devices where so critical the crew would have portable
scanners.

------
dennisgorelik
Airlines should encourage passengers to keep their mobile devices on.

That would allow pilots to test their equipment and make sure there is no
dangerous interference with passengers' mobile devices.

~~~
ShabbyDoo
Your comment made me think of Netflix' "Chaos Monkey" -- the system which
randomly disrupts PRODUCTION systems:

[http://www.codinghorror.com/blog/2011/04/working-with-the-
ch...](http://www.codinghorror.com/blog/2011/04/working-with-the-chaos-
monkey.html)

Perhaps eliminating restrictions on electronics use would have a similar
effect. What if the FAA started out by allowing use on a select number of
flights where the pilots were highly trained and aware of the supposed risks?
Over time, restrictions could be lifted more broadly presuming these initial
experiments showed no cause for concern.

------
joshfraser
This is one of those rules that I feel completely fine breaking. I just wish I
didn't have over-zealous flight attendants yelling at me all the time.

------
Mordor
That there's no recorded incidents relating to everyone switching on/off
simultaneously highlights the lack of risk.

------
BCounsell
Even on the slightest chance that a consumer device would cause interference,
do you think having to put them away is so bad? On take off and landing you
are also near other planes, populated areas.

Also don't forget with the 3.5 oz limitation someone did use that kind(Liquid)
as an explosive to try and take down a airplane. poor electronics getting
jolted from a peaceful sleep with a bullhorn.....

------
1point2
1\. When so much is at stake to err on the side of caution seems reasonable.
2. I have not been in a plane for a while - so can't quite visualize what it
looks like - but in the event of an emergency abort on take off, or a landing
that goes wrong - having all loose items stored is a head start in ensuring
ones iPad does not become an iGuillotine. Just a thought.

~~~
silencio
This is why I always look warily at the cups of hot coffee, salads, hamburgers
and foods with plastic knives, glass bottles, physical books, newspapers
everywhere, babies with their toys and more when I fly 2+ times a month,
right? On top of the food and drinks being served to people flying anything
but economy class.

I'll take my chances with an iPad in somebody's hands flying into my face over
a cup of scalding hot coffee splashing everywhere any day.

It's one thing to tell people to put things away or to watch out for safety's
sake during important times like landing/takeoff and turbulent areas (and
really, that should only extend to things like clearing the aisles and trays
and armrests), and it's another to justify a questionable demand like "turn
off your cell phone" in the name of "safety".

------
baby
I actually never turned off my phone/gameboy/mp3 player and that since ages.

------
FForbes400
So, when you fly private what do they ask of you?

------
ambertch
that's why I just don't turn off my devices

------
wavephorm
The luddites win sometimes.

------
Craiggybear
I think its because that if there were an accident involving the spill of
aviation fuel (even in an aborted takeoff situation, I can see that happening)
then the danger of ignition would be that much greater if everyone's phones,
tablets, laptops, etc were all in a powered-on or RF transmit mode.

It makes good sense to minimise that risk.

I recall years ago you were not permitted to use a cellphone on the forecourt
of a gas station. No one seems to remember or bother about that now.

~~~
mafro
FACT: the risk of my mobile phone igniting vapourised fuel in a gas station
forecourt is almost exactly equivalent to the probability that my ipod nano
will tangle with an airplane's cockpit electronics.

It's all myth and fud spread by a) people with ulterior motives (see above) b)
people who are too uneducated or too stupid to make their own judgement. Like
air hostesses, petrol attendants.

~~~
wglb
Inside your iPod nano, or any other device with a computer chip is a radio
transmitter. Inside the cockpit are many radio receivers, some of which are
pretty critical to the proper flight of the airplane. Your radio transmitter,
and radio transmitters being run by other passengers, mix and mingle their
signals, producing an unpredictable effect on these key cockpit receivers.

The probability that this happens is not zero or low, but very high.

~~~
aceofspades19
1\. Not all devices with a computer chip have radios, my TI-84 calculator has
a Z-80 processor but there is no radio in it 2\. Aircraft radios operate on a
very different frequency then consumer electronics, and I'm pretty sure the
FCC wouldn't allow consumer electronics to operate on the same frequency as
the radios in a cockpit regardless

~~~
CamperBob
Technically, yes, there is a "radio" in your TI-84. The Z-80 is clocked by a
crystal oscillator, which runs at a few MHz. Some of that energy will escape
in the form of electromagnetic radiation. Sensitive instruments (including an
ordinary AM radio) can pick up this radiation from distances ranging from a
few inches to several yards. This is true of essentially all modern
electronics, although the frequencies have obviously gone higher and higher
over time.

If it were true that the RF energy levels emitted by FCC Part 15-covered
consumer electronics could interfere with aircraft systems, it would be
utterly unthinkable to permit them on board in the first place, whether
"powered off" or not. The TSA would be confiscating Game Boys, not bottles of
water. Since that isn't happening, it's difficult to avoid the conclusion that
the prohibition is just one more exercise in bureaucratic security theatre.

~~~
andrewescott
If all electronic devices were dangerous, airlines would be asking passengers
to remove the batteries from their wristwatches for the duration of the
flight.

------
acheron
It's because everyone hates each other while flying anyway, and if people had
to fly 5 hours with some dumbass yelling on his cell phone the entire time
there would be a lot more incidents of "air rage".

