An airplane announcement I’ve been waiting for

I blogged a few months back about how ridiculous the rules are regarding the use of electronic equipment on airplanes. I often leave my iPod on, and sometimes (gasp!) my laptop, which I leave secretly running inside my briefcase. I am happy to report no problems so far.

A flight attendant did something on my flight a few days ago that I have beeen waiting to hear for a long time. After the initial announcement that everyone had to turn off their electronic devices, she let a few minutes pass. Then she got back on the microphone and said, “According to the reading on my equipment up front, there is still one cell phone turned on, so please check that you have turned yours off.”

Obviously, she has no equipment for detecting this, but you should have seen the passengers scramble to check their bags. Except for me, of course. My laptop hummed happily along under the seat in front of me. Still, brilliant on the part of the flight attendant, although I think it would have been more convincing coming from the pilot.

The Economist, meanwhile, picked up on a theme mentioned in my past blog post regarding the nonsense in the ritual airline safety message about “in the unlikely event of a water landing…” Here is the Economist’s version of the in flight announcement we really want to hear (although you may need to be a subscriber to follow the link).

And, finally, let’s hope you don’t have to sit next to me on your next flight. Not only do I put you at risk because I don’t turn off my iPod and thus interfere with airline communications, but TSA just confiscated my deodorant and my toothpaste. Of course they let me keep my contact lens solution. Hmmm…if I were a terrorist, don’t you think that I could figure out how to take the top off a bottle of contact lens solution and put my explosive liquids in there? It is totally pointless to enforce rules which impose costs on innocent people, but are easily circumvented by terrorists. Can anyone think this is accomplishing anything productive?


The current regulations on liquids and personal hygiene products do 3 things:

1) Help the public feel that the government is doing something
2) Require you to buy food, drinks, emergency personal hygene pieces once you pass security and then dump any remaining extras when you board
3) Remove one of the most common complaints on airplanes about "not enough storage space in the overhead compartments" and speeds up boarding time (allowing for more on-time bonuses and better DOT arrival times)

As such the government has no motivation to relax regulations. The airport's profits are rising as well as those companies that sell items beyond security, so they have little reason to pressure for relaxed regulations. The airlines have very little reason to relax regulation as it solves many of their headaches and they can blame the bad parts on the airport security and the government.

In short, be prepared to live with the new regulations a long time silly or not. No one has an incentive to remove the regulations.



I'm no scientific expert so I'll defer to the Myth Busters, et al., regarding cell phone use because of their radiating nature. However, I still don't see a scientific explanation regarding electronic devices, particularly during takeoff and landing.

From what you all are saying, it might interfere with certain controls and displays. But to what extent? Wouldn't the potential effects of a problem matter more while you're in the air, versus already on the ground? Is a potential problem flight critical -- i.e., would it affect the controls, engines, etc. -- or would it just be an annoyance to the pilots?


To clarify, the point of my comment is: Is there a difference between the radiating nature of cell phones versus other non-communicative electronic devices? Could Ipods and such cause as much potential cumulative damage as cell phones, Blackberries, etc.?


The best cellphone related announcement I've heard was given by Suzy Menkes, of the IHT, at a conference. She invited all the CEOs and Managing Directors in the audience who's businesses were in such a precarious position that being out of touch with the CEO would be a disaster to leave their phones on. Rest assured there wasn't a single ring all conference.


I'd guess that people pointed it out in your earlier post, but Wikipedia (bastion of accuracy that it is) would like to disagree with your opinion that commercial flights never ditch safely in water.

As for electronic devices on flights, an earlier commenter has already mentioned that on US flights there are usually a handful of cellphones turned on. The same research demonstrated that cellphones actually cause less interference in the bands used by on-board equipment than laptops, hand-held games and other personal electronic equipment.

I'm in two minds about the dangers. Stupid people have been ignoring the instructions for long enough that using laptops has probably been proven safe. On the other hand, there have been demonstrable occasions on which passenger electronic equipment has interefered with the operation of older aircraft. At the very least, you could never be sure that it was your laptop that was causing the death plummet, so you wouldn't die feeling guilty.



coupla quick things:
1. The Economist made a serious error when they said take-off was the most dangerous time of a flight. Actually, it's the safest. Landing, however, is extraordinarily dangerous.
(They made one or two other errors or exaggerated dismissals, but these aren't relevant here.)

2. In very recent times, mobiles have become useful as remote detonation triggers. So there is an argument for scanning for mobiles and confiscating them, or, better, for jamming them continuously in flight.

3. But, historically, the BIG problem with electrical kit being active in flight is not with normal use, but with defective kit.
Normal use IS fine.
But it's almost impossible to predict if or how particular items might deviate from normal tolerances. For example, a particular phone-set might be accidentally sat on such that the new aerial kink now radiates freakishly, or that a given wifi card is failing and intermittently "sparking" radio waves which have no effect on the wifi signal but may interfere with one of the plane's systems or data sensors.

Accidentally throwing showers of radio "chaff" when the plane is landing, confusing the plane's systems ("You SURE we're at 800 feet?") at a time where there is little margin for error and high penalty for error, is the risk they seek to prevent.

Reports ARE filed --very rarely-- of pilots having to lunge to disable the automatics then go round and come in again on pure manual (not fun at a strange airport) because the systems either failed or, much worse, showed erroneous data, where these failures were traced to passengers deciding it was safe to start turning on electrical kit because they were nearly down.

A few decades ago, Melbourne airport in Australia was being periodically shutdown by an enormously bright jamming device that swamped every ground radar, let alone the planes'. It was enormous, but intermittent and random. And very hard to trace as a result. Finally, it stayed on long enough for them to trace it precisely.

It was a clothesline. With a bent arm. And when the wind blew gustily on a certain angle, it became a radio source.

We are very spoilt in these days of digital everything and our relatively well controlled personal environments and the clever work and forethought of the engineers who have gone before.
But that doesn't mean that the analogue world has gone away. And defective or damaged or flexing electrics can easily swamp normal digital margins. And you only have to get unlucky once...



=Hmmm…if I were a terrorist, don't you think that I could figure out how to take the top off a bottle of contact lens solution and put my explosive liquids in there?=

That is exactly what Ramzi Yousef and Khalid Mohammed attempted to do to 11 Asia-USA flights in 1995 with their "Oplan Bojinka" operation:

"Yousef was the explosives expert, and he began designing new and better bombs. Chief among them was a "microbomb" for use on airplanes. The device used a Casio digital watch and a contact lens solution bottle filled with nitroglycerin. It made for a virtually undetectable bomb which could be set on a timer.",,1841679,00.html

Track to BoingBoing post of this item:

All the best,


PS, re Explosives:
This is a 10second video of a test of only *200 GRAMS* of semtex vs. a jumbo.
details here:
source: Aviation Weekly and Space Technology
video: CNN

You will note the rear falls off.

However, it's not clear if the explosive was laid in a way easily achievable by a passenger. So in practice, a terrorist might need more.

However, at the risk of sullying my point with a non-formal source, Mythbusters had a chilling episode where they blew out most of the rear-left side of a passenger jet using less than a toothpaste tube's worth of standard commercially-available paste explosive arranged on stiff card curled round and stickytaped to make a cone.

Now, what if someone used say TWO toothpaste tubes/shampoo bottles/etc's worth of explosive, and put that cone face down over the wing root? I'm guessing, but I suspect that would be sufficient to cause the plane to break up in flight.

The unfortunate point is: while the apparently over-onerous restrictions really chafe, they are perhaps less irrational than they appear.



I was on a flight from New York to Los Angeles. I turned on my ibook after the flight attendant made the announcement that it was safe ti turn on electronic equipment. After about twenty minutes into the flight, a flight attendant came back to where I was sitting and asked if my laptop had a wireless device. I said that it did, and she said the pilots were noticing some interference in the cockpit, and asked if I could try disabling the wireless for a moment. I turned off the airport device on my ibook, and the attendant went back to the cockpit. She returned a moment later and said that it had seemed solved the interference problem, and requested that I keep the airport off for the remainder of the flight.


#3 (Joseph) and #26 (Saltation) have given me something new to worry about on my upcoming international flight. Thanks a lot.

But, Saltation, can these be effectively jammed without affecting the navigation system? If so, why not?

After liquids were banned, a co-worker who used to work in the defense industry and had a decent clearance level said that the problem with liquid explosives had been known about for a long time, just ignored. Is this a similar case?


I love the fact that they took your toothpaste and deodorant, but that you were allowed to keep your contact solution. In the history of terrorist attacks the only one of these three items that has ever been used in a bomb is the contact lens solution container. Mr. Ramsi Yousef (remember him?) of Al-Qaeda and WTC(1) fame constructed a bomb in the lavatory of Philippine Airline Flight 434 on December 11, 1994. Like a true chickenhawk, he got off the plane before the explosion, but he did manage to kill one innocent person.
TSA has been making claims lately that certain nefarious types could mix together a TATP (triaceton-triperoxide) bomb on board an aircraft. This is the reason given for the new restrictions on liquids, gells and aerosols. The reality is that mixing TATP requires a carefully controlled environment. The mixture must be kept at a temperature below 50 degrees farenheit. This requires a constant supply of fresh ice. The mixture must also be allowed 24 hours to crystallize - the crystals are the explosive componenet. Apparently the TSA thinks modern air travellers are so stupid that they will not notice the steady parade of ice buckets being transported to the constantly occupied lavatory over the course of the 24 hour (plus) flight. And of course you won't notice the prodigious amount of noxious fumes being re-circulated through the air conditioning system. (Think cat-hoarder plus meth lab.)
The new restriction are either:
1) A conscious attemt to keep the flying public fearful, and therefore more likely to submit to the next transgression of their right.


2) A knee-jerk reaction by some Homeland Security executive who was appointed not on the basis of his security background but as a result of his political connections.

Either way we as Americans have already lost the battle, and unless things are changed we will lose the war.



It's interesting to me how learning more about the author's personal approach to life takes away from my enjoyment of what I think was a fantastic book. This is perhaps one of the ironies of blogging.

I'm astounded by the arrogance of people that proudly proclaim that they've left their cell on, or in this case that they've left their laptop on, "humming away happily...."

It's disturbing to think that one person can presume to bash the safety-regulations (whether they think they are accurate or not) by taking a chance on jeapordizing the safety of other passengers around them.

I travel over 100K miles a year on planes and I don't think there's an awful lot of validity to the cell phone / laptop ban --- but until someone more qualified than I (and certainly more qualified than an economist on this subject) I am prepared to be respectful to the other people on the flight and not leave on all my equipment -- at a minimum I certainly wouldn't boast about it.

Odd, at best.



What a remarkable waste of time, money, and mental energy we spend debating politically contrived issues with connections to our safety that have become altogether arbitrary. Every issue under the sun, from one point of reference or another, potentially concerns our safety.

Let's just as well argue how much we jeopardize our kids' safety everytime we don't send them outdoors in a full suit of hockey equipment. What is this life about? Above all, I am to understand, it is "safety".


It's simply not possible that aircraft wiring can be significantly interfered with by an iPod- which interestingly enough, does not have an "off switch". or removable battery. The emissions from the ipod wouldn't be much more than a travel alarm clock or other devices that don't really turn off. I know people that have wireless devices in their wristwatches, bluetooth earpieces for their phones, wireless transmitters for their automobile locks, etc. Many of these things simply can't be turned off, and it's obvious that they are not significantly affecting air travel safety.

I'd recommend switching off radio transmitters though such as wifi and mobile phones- they waste the batteries of the device. A running laptop with the wireless radio off and an LCD screen has lower emissions than the CRTs they use to show the safety videos and in flight movies.

Have they started selling miniature toiletries kits as you get off the plane? They could make them up from the items confiscated from boarding passengers. The airports could use this money to buy more explosives detectors.

The hysteria around and obsession with terrorist attacks on planes is an interesting extension of the general lack of understanding of the physics of airline flight. I haven't heard anyone attempting to ban cell phone use on buses, subways, trains, etc. I think the general irrational fear of flying makes terrorist threats on air travel to be more effective at making people respond to their demands.

It's really sad to see so many of you sheep criticizing Levitt on this. He's not jeapordizing your safety, he's just not interested in blindly following the rules. It's certainly worth packing toiletries in the hopes that a poor inspection job will spare you the inconvenience of purchasing them at your destination. The current ban on liquids is beyond inane, it goes into the realm of the aggressively stupid. The human body is significantly composed of liquid, perhaps once we ban those from planes, and from security policy making, we will truly be safe once again.



Inane rules & control

The cell phone ban & wifi may have some validity. The difficulty is in proving a negative, that cell phones (and any other device) do not cause problems. This is difficult to proof, given the wide variety of aircraft and electronic devices. Each one (and possible many combinations) would need to be tested show no problems. This a very costly task for the airline industry (airlines, airplane manufacturers,etc). So it is much cheaper for them to simply ban these devices on the off chance they may cause problems.

Interestingly, Radios, TVs and GPS devices are also banned. These have the same interference characteristics as do PCs, iPods, DVD players. This is more likely do to the fear of information not controlled by the airline staff.

The reaction to the reported bombers of Britan who were planning to make the bomb on the airplane is way over the top in my mind. Although Hollywood has made many movies about binary liquid type bombs, there is no known chemicals like this. The planned bomb making would have been difficult. The chemicals in question (H2020) are not stable in high concentrations needed and are shock sensitive. The 3% vaiety commonly available is too weak to produce enough material. The mixing of the chemicals requires an ice bath. And the required time would to make enough material for a bomb would be on the order of 8 to 10 hours with the right materials. The bomb makers were unlikely to succeed with this method.

Although bombs are bad, the airplane will still fly! The Hawaii flight which lost a good chunk of the airplane flew and landed fine. The bomb would need to set off the fuel tanks to be effective.

From a statistical point of view, the number of successful hijackings, bombings, etc. are small compared to the overall amount of flights. Driving a car is still less safe. Why do we accept the odds on driving a car?



I think to say that, "It's really sad to see so many of you sheep criticizing Levitt on this...He's not jeapordizing your safety, he's just not interested in blindly following the rules," misses the broader point.

There are two issues here: 1) Do the rules have any validity, and 2) In the absence of clear evidence one way or the other, do individuals have the right to "ignore the rules," at the risk of jeapordizing other individuals.

Many of us agree that aspects of the current TSA rules seem ridiculous. The liquids ban might be an example. Others, however, (and I note most of them appear to be avionics engineers, eletrical engineers, etc) seem to suggest that some of the electrical issues may in fact have some validity. They don't seem to eager to suggest that these rules should be ignored willy nilly.

I suspect some of you may assert that these engineers are sheep too; but from my perspective they are better educated sheep than I on this subject and I can't fathom a society where, on issues of collective safety, one person can just decide to "not blindly follow the rules," and be applauded for it.

Why should someone not well trained in these issues be able to make the call on what's a problem and what's not when I'm trapped with them at 35,000 feet with no means of protecting myself. And what about the other 200 people jeaporidized by somenoe who isn't interested in "blindly following the rules?"

I suspect that statistically there is a very low frequency of idiots blowing themselves up in gas stations because they are smoking at the pump. But if I'm pumping gas and some moron walks up to me and says, "well that's a stupid rule and I'm going to light up right here," I'd tell him to get away from me.

100K fliers like me see these guys all the time. They talk over the safety announcement (usually loudly), continue to use the phone after they've been asked to turn it off (usually loudly), stand-up when the seatbelt light is on,check their Blackberry's as soon as they're close enough to the ground during the landing procedures(my favorite), listen to their Ipods when they're asked not to, leave their laptops on under their seat.....

Personally, I think it has nothing to do with their "evaluation" of the validity of the rules, and everything about their sense of having their personal space "infringed," even as they impose themselves on others.

But, whether you agree with that or not, certainly we would all agree that the best way to get the rules changed is not just to ignore them - that is sophomoric at best.



Hondo- Given that Scandinavian airlines and Lufthansa offer WiFi from Boeing on some flights, it would seem that avionics electrical system insulation is a surmountable problem. If the systems were really that sensitive to SNR issues and are so poorly insulated, wouldn't they all interfere with each other? It just doesn't make sense.



I think it would help if the airline safety ritual included factoids that explain the rationale for the instructions.

Example: "Please secure your own oxygen mask before assisting your child." No parent alive would obey this directive, unless the reason was drilled into their heads. In certain cabin pressure situations, you may begin to lose consciousness in 11 seconds. (Source: Salon, "Ask the Pilot.") That is not enough time to secure both masks, and may not even be enough time to secure the child's mask. But if you secure your own mask it's OK if the child blacks out because you can then secure her mask to alleviate the situation.

Example: "don't inflate your life vest until you leave the plane." Water landings are "unlikely" but the ditching article does point out several instances where passengers were alive and swimming. In the crash off the beach of an African resort, survivors only had to make it about 500 years to the beach. But dozens died because they had disobeyed instructions and inflated their life vests early. As the plane filled with water, the inflated life vests inhibited their movement and they drowned.

And I have to complain. We all know the safety regs are overly conservative. But please take a minute to outline YOUR qualifications to determine unilaterally whether they apply to you. Are you aware of how these devices operate, and the implications for that particular aircraft? In other words, I guess I'm wondering WTF you think you are?

My reading of the Mythbusters experiment is that a few devices are harmless but several dozen, or a couple hundred, could indeed have an impact. It is a surmountable problem but until we get the go-ahead from the people operating the actual aircraft, I intend to obey the rules. Because I don't have this strange idea that I am special.



As pointed out: the criticism isn't that Dr. Levitt is "jeopardizing our safety," but that he is making it sound like silly acts of defiance are science.

Leaving one machine on is a preposterous test of the hypothesis that a planeful of on-machines would have no effect on plane function. That is nothing like an experiment, and it proves nothing. (For starters, the effect of one person doing A vs. everyone doing A can be very different.) One need not be an engineer or scientist to know that. And an empirical economist should certainly know that.


Perhaps this article from 1933 answers all of our questions: