# What would happen if all passengers of a Boeing 747 would using their cellphone during take-off **URL:** \ **Category:** Factual Questions\ **Created:** [August 18, 2011, 11:45am UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140 "2011-08-18T11:45:48Z")\ **Posts on this page:** 8\ **Page:** 3
**Author:** ![Zeriel](https://avatars.discourse-cdn.com/v4/letter/z/58956e/32.png) [@Zeriel](https://boards.straightdope.com/u/Zeriel)\ **Post date:** [August 21, 2011, 2:41pm UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/41 "2011-08-21T14:41:08Z")
> [@ricksummon](#): > > But seriously, a terrorist could probably rig up some kind of dedicated jamming device disguised as an innocuous device and simply stuff it in his carry-on luggage. I’d honestly be surprised if something with a battery big enough to be significant could pass security, but I’m not sure about how much total power output you’d be able to get from something the size of an extended-cell laptop battery (about as big as I think you’d be able to get aboard these days). The two main problems with this tactic are 1) it’s “only” going to jam up the instruments/radio at worst, which is not enough to take down an airliner except on approach in bad weather, and 2) the timing of their use would have to be such that the pilot couldn’t wait out the battery of the device (which is going to be draining at a relatively prodigious rate). ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 21, 2011, 3:27pm UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/42 "2011-08-21T15:27:05Z")
Tris: You’re wrong, period, amen. The TSA has a set of responsibilities under the law. Those responsibilities do NOT extend to aviation safety, only aviation security. So the fact the TSA used to prohibit nail \*scissors \* (they never prohibiuted nail _clippers_, and they do not now prohibit nail scissors) is irrelevant to any regulation or lack of same on cell phones. If there was a way to hijack or reliably crash an airplane with a cellphone, they too would likely be prohibited by TSA. The FAA has regulatory authority over aviation safety. As the links provided by Duckster explains, the situation with cell phones (all PEDs really) is complex. Prior to the advent of PEDs, the attitude of the FAA is that absolutely everything is prohibited until a formal testing program has proven it’s safe to umpteen decimal places. The airplane manufacturers can’t even change the brand of #10-32 machine screw or light bulb they use without formal engineering proof that the new ones are as good or better than the old ones. When the first PEDs (“transistor radios”) came out in the 60s, there was a very real engineering concern because the IF stages of AM & FM radio \*receivers \*operated on very similar frequencies to the primary navigation system of the day, VOR. The signals inside the coax running from ground transmitters 150 miles away into external antennas then into aircraft radio receivers are measured in microvolts. That a passenger’s radio’s electronics could be situated a couple feet away from antenna cabling and be pumping out interference stronger than microvolts is very plausible. In fact it’s happened. So radio receivers were prohibited. Fast forward 50 years. Now we have lots of personal transmitters. And nobody in the consumer electronic business is doing anything to certify their stuff as safe for aircraft. And although the latest aircraft & avionics are built with PEDs in mind, all the old systems are still there too. Only the 787 & A380 designs were begun after 3G cellphones became ubiquitous. Any other aircraft type (i.e. every airliner in the world today except a few dozen A380s) was designed before 3G cellphones existed. Most of them were designed before \*any \*cellphones existed. Interference happens. We see it frequently. Because we can’t positively establish causation, nothing can be reported or done. The most significant inflight hazard is that the navigation system used worldwide for low-weather landings (ILS) is 1950s technology. The frequencies & signal formats are what they are. They are susceptible to PED interference. Hence the specific prohibition to turn absolutely everything off for arrival. The FAA is in a crack. They have regulations which recognize the threat, but they shift the burden of safety onto the carriers. Why? Because they know as a matter of legal authority and practical politics that they can’t mandate the level of testing & certification required to \*prove \*that your personal collection of devices is safe to umpteen decimal places, or require you to leave them at home if they aren’t on the approved list. The airlines are in a crack. They can’t practically prevent people from bringing PEDs onboard in checked luggage, carryon luggage or on their person. They don’t want to piss off their customers. They want the aiplane manufacturers to design interferance\*-proof \*airplanes. That’s -_proof_, not -_resistant_. As a matter of engineering reality, the manufacturers cannot make interference-proof airplanes until they determine what they’re making them -proof _from_. And at the rate consumer electronics advance, thats logically impossible. A fresh aircraft design started today will be delivered in about 2020. And be in use to 2060. If we could get worldwide regulation on the permissible nature of PED transmissions both deliberate & inadvertant, that would at least give the avioncs engineers a target to aim at. Fat chance of that. Finally, passenger’s attitudes that this is all some scam to sell airphone use, or some bureacratic CYA are a large part of the problem. If I was King we’d treat somebody firing up a PED at a prohibited time or in a prohibited mode about the same as we treat somebody who starts playing with matches. This is a tough problem. if I was King we’d have an effective RF interference receiver which could alert us that something unexpected is transmitting someplace aboard our aircraft. And the FAA would be running a comprehensive data gathering program to for us to report these occurrences. In reality, everybody’s looking the other way & hoping the next generation of nav systems can be designed to be close enough to -proof that we don’t care what gizmo’s people use. And that the odds are good enough that no accident will happen in the 20+ years it will take to deprecate the existing nav systems worldwide. I will say the odds are exellent that no accident will happen in the meantime _whose investigation will blame PEDs_. But there is almost certainly going to be an accident which \*should \*be blamed on the PED which will cause it. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 21, 2011, 3:40pm UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/43 "2011-08-21T15:40:50Z")
Late add: Or has already caused it. ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [August 21, 2011, 5:10pm UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/44 "2011-08-21T17:10:30Z")
Still waiting on the link to a report by anyone, anywhere, anytime that a cell phone caused any problem on any airplane. Tris ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 21, 2011, 6:00pm UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/45 "2011-08-21T18:00:14Z")
> [@Triskadecamus](#): > > Still waiting on the link to a report by anyone, anywhere, anytime that a cell phone caused any problem on any airplane. That’s easy. I found this in about 30 seconds of searching. Effects of Interference from Cellular Telephones on Aircraft Avionic Equipment From the Civilian Aviation Authority (UK) > [@](#): > > 1.1 Between March 1996 and December 2002, the number of aircraft safety-related > incidents that cited cellphones as a factor, as reported to the UK CAA in accordance > with the UK Mandatory Occurrence Reporting legislation, totalled 35. > 1.2 The reports linked interference with effects including: > • False warnings of unsafe conditions (e.g. baggage compartment smoke alarms); > • Distraction1 of the flight crew from their normal duties; > • Interrupted communications due to noise in the flight crew headphones; > • Increased work load for the flight crew and the possibility of invoking emergency > drills; > • Reduced crew confidence in protection systems which may then be ignored > during a genuine warning; > • Malfunctioning of multiple systems essential to safe flight. From here (warning - PDF): [www.caa.co.uk/docs/33/CAPAP2003\_03.PDF](http://www.caa.co.uk/docs/33/CAPAP2003_03.PDF) The FAA and FCC probably keep a similar list but I didn’t find it in my brief search. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 21, 2011, 6:03pm UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/46 "2011-08-21T18:03:25Z")
There is also this, from ABC news. I did not track down the original report that this is based off of. > [@](#): > > A report by the International Air Transport Association, a trade group representing more 230 passenger and cargo airlines worldwide, documents 75 separate incidents of possible electronic interference that airline pilots and other crew members believed were linked to mobile phones and other electronic devices. The report covers the years 2003 to 2009 and is based on survey responses from 125 airlines that account for a quarter of the world’s air traffic. > > Twenty-six of the incidents in the report affected the flight controls, including the autopilot, autothrust and landing gear. Seventeen affected navigation systems, while 15 affected communication systems. Thirteen of the incidents produced electronic warnings, including “engine indications.” The type of personal device most often suspected in the incidents were cell phones, linked to four out of ten. ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [August 21, 2011, 8:20pm UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/47 "2011-08-21T20:20:44Z")
Thank you for the links. I will be reading them this evening, and will respond when I have finished. Tris ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [August 22, 2011, 12:25am UTC](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140/48 "2011-08-22T00:25:10Z")
Read the links. The second one seems pretty close to being anecdotes from parties with probable conflicts of interest, in a scientific sense. All alone it would not convince me. However, the first link was definitely meticulous in its experimental design, and within reason in its conclusions. It seems to me now that the possibility exists in “worst case” scenarios that actual interruption to flight systems is possible from cell phones. New communication devices seem even more likely to cause problems, so I assume the problem is of no concern to phone designers and manufacturers. This causes me to wonder, why cell phones are allowed on flights at all. But I accept that the actual risk does exceed that of poltergeists. I also wonder why airport warnings don’t include at least references to supporting experiments. So, my ignorance is fought. Thank you. Tris [Previous page](https://boards.straightdope.com/t/what-would-happen-if-all-passengers-of-a-boeing-747-would-using-their-cellphone-during-take-off/593140.md?page=2)