Things I have always wanted to know: Cell Phones

[El Presidente]

 TIHAWTK : Things i have always wanted to know. 

 

Boarded, sat down, worked and then told by the nat the lovely stewardess to put my phone to flight mode. 

I simply asked....."Technically...why?"

.....that stumped her. 

 

So in a first of a series (and anyone can post a question in the same format) just start a new thread. 

 

can a "live" mobile phone bring down an aircraft?

.....if so ....why are we flying 

 

 

[NSXCIGAR]

A commercial plane has never been significantly compromised by a cell phone or other portable device, although there was one incident in which a DVD player interfered with instrumentation on a 727 in 1999--that plane is out of service today.

This passage can be found in the wiki article which basically sums up the airlines' stance on the matter. Interestingly, the FAA does not prohibit the use of phones--it is apparently the airlines who have made it policy, at least in the US:

A 2000 study by the British Civil Aviation Authority[13] found that a mobile phone, when used near the cockpit or other avionics equipment location, will exceed safety levels for older equipment (compliant with 1984 standards). Such equipment is still in use, even in new aircraft. Therefore, the report concludes, the current policy, which restricts the use of mobile phones on all aircraft while the engines are running, should remain in force.

https://en.wikipedia.org/wiki/Mobile_phones_on_aircraft#Electromagnetic_interference

 

[NSXCIGAR]

3 minutes ago, toofargone said:

It's funny though. On Qantas planes they now have a WiFi based streaming service that you can use to play movies / music in flight. I fail to see how airlines can ban the use of mobile phones on board whilst allowing the use of WiFi in flight. If a mobile phone can cause interference surly a WiFi signal can as well..

I believe EM interference from WiFi is only significant on 802.11b and 802.11g which are pretty outdated standards (2003, 2007). Modern WiFi should produce far less or no EM interference that could affect an aircraft's instrumentation, hence the airlines allowance of it.

[El Presidente]

....what % of phones are not turned off on any given flight ....maybe just on mute.......10%-20%-30% 

Consequences? planes landing cancun as opposed to Cincinnati,  Shanghai as opposed to Singapore. 

I dont know but it doesn't appear to pass the sniff test 

 

[NSXCIGAR]

9 minutes ago, El Presidente said:

....what % of phones are not turned off on any given flight ....maybe just on mute.......10%-20%-30% 

Consequences? planes landing cancun as opposed to Cincinnati,  Shanghai as opposed to Singapore. 

I dont know but it doesn't appear to pass the sniff test 

Many are left on--of that I have no doubt. The jist of the 2000 BCAA study is that it's highly unlikely that any device could affect an aircraft--certainly not substantially--even when used close to the cockpit, but since it "exceeds safety standards" they err on the side of caution, since some aircraft still do use 1984-compliant instrumentation. 

It's probably completely safe as thousands of planes take off with thousands of cell phones on and have for over a decade with not even one report of a problem.

 

[foursite12]

Usage via an approved (read billable) app will suddenly overcome all safety concerns.

[gweilgi]

59 minutes ago, El Presidente said:

....what % of phones are not turned off on any given flight ....maybe just on mute.......10%-20%-30% 

Consequences? planes landing cancun as opposed to Cincinnati,  Shanghai as opposed to Singapore. 

I dont know but it doesn't appear to pass the sniff test 

 

My brother has a habit of not turning off his phone when flying.  

I have a habit of ringing him when I know he is on board.

Consequences?  Annoyed cabin crew, the odd panicked fellow passenger, and one seriously ticked off sibling.  As far as I am concerned: Result!

 

[SticksAndSticks]

I asked a pilot friend of mine once and his answer was that because of the increased risk during takeoff and landing they don't want people distracted by their phone in the event of an emergency.

That said, I usually leave my phone on because if something is happening to the plane during takeoff or landing I'm happy to put my phone down and focus on not dying.

[LordAnubis]

I would imagine this no phones thing also adds to the "alertness" of passengers during take off and landing.

Seats upright and tables folded away and no bags at your legs, so the path is clear for evacuation. Cabin lights off for night time take off and landing so that you can see out the windows at what hazards are out there more easily. Headphones off so that you can hear whats going on. Phone away so that you're not facebooking while the plane is burning.

I've had to emergency evacuate a plane before. It's carnage. And that was only a small plane! An A380 would be pretty much impossible to evacuate i would imagine.

[EndangeredSpecies]

I was once told it was fcc over concerns of a large volume phones jumping from tower to tower, which could potentially bring down the tower momentarily. This article seems to have a line that would briefly support that. https://www.usatoday.com/story/news/2017/04/10/voice-call-ban-planes-cellular-service-airlines-federal-communications-commission/100291108/

the main reason (or at least my reason) for turning off a phone, or putting it into airplane mode these days is so it isn't constantly searching for service once your above 10000, which can drain the phone rather quickly. 

[EndangeredSpecies]

1 minute ago, toofargone said:

Don't most aeroplanes have a USB port in the seat handle so you can keep them charged?

It doesn't really bother me, I just turn it to plane mode, it's not like you can get a signal at 40,000 feet anyway.

They do now yes, but I also occasionally fly private. Of course I also carry around portable chargers these days, so I never have an issue. 

[Fuzz]

 

[Fuzz]

4 hours ago, LordAnubis said:

I've had to emergency evacuate a plane before. It's carnage. And that was only a small plane! An A380 would be pretty much impossible to evacuate i would imagine.

But that was because you were in the emergency aisle seat and were too short to reach the handle to open the emergency door...

[westg]

51 minutes ago, Fuzz said:

But that was because you were in the emergency aisle seat and were too short to reach the handle to open the emergency door...

you would know...I think Mus is taller than you......Rob do as you are told... poor Nat

[ayepatz]

Never seen a petrol station blown up by a mobile phone, either, come to think of it.

[Fuzz]

37 minutes ago, westg said:

you would know...I think Mus is taller than you......Rob do as you are told... poor Nat

I stand a hair taller...

[PapaDisco]

Yes, definitely possible.  I've seen the failure mode in action.

10 years ago I used to keep a pretty zippy general aviation plane outfitted with Collins radios, same as the airliners used.  I, or my wife, would routinely make cell phone calls at lower altitudes (arranging hotels, rental cars, whatever) on my Motorola phone (and pilot stores used to sell headset jacks just for this purpose).  And as Endangered Species said, the cell tower jumping was a nuisance, and at 25,000' the phone wouldn't work at all . . . but that's not the point of my story.

One clear, sunny day as I was following the localizer (that's the radio beacon airliners use for approaches in zero visibility) in just for fun I saw the needle jumping full scale to the right, yet I was lined up perfectly with the runway (it was clear VFR weather, not a cloud in sight).  I could also hear that distinctive intermittent buzzing sound in my headset as the cell phone in my pocket would register with the nearest tower (you can also hear this when you put a cell phone close to an FM radio).  On landing, I tried the phone and it worked fine, but its transmitter was just enough out of whack to now drive my NAV receiver off scale, which would have put me somewhere other than the runway if it had been a heavy weather day and an approach to minimums.  

The inherent problem is that radio spectrum over the last 100 years has been getting divied up as things were invented, not as it ultimately made sense, and so when the cell phone was invented they got slotted in between the aviation frequencies.  If your phone transmitter goes out of spec a bit, you could be chatting in one of the Nav frequencies and sending the cockpit VOR/Localizer for a spin . . . in theory.  It's a risk for the Nav frequencies, not the Com frequencies.  

Now, I was sitting in the pilot's seat of course, right next to the radios and pretty close to the antennas.  In a big commercial aircraft you won't be anywhere near the cockpit, but you might be close to one of the antennas.  And someone may argue that current phones are more reliable . . . (can you say "Samsung Galaxy 7??"  ), but me, I turn my phone the f*ck off when on a plane.

[Colt45]

9 hours ago, El Presidente said:

 I simply asked....."Technically...why?"

Are you related to Alec Baldwin?

[wabashcr]

My understanding is that there's only anecdotal evidence that mobile phone signalling could interfere with aircraft instrumentation.  The frequencies involved aren't harmonics, so in theory it should take a malfunction for one device to interfere with another.  Considering cellular base station antennae aren't directed skyward, in most parts of the world you'll struggle to get much of a signal above 10,000 ft anyway.  With older cellular technology, searching for a signal would be a huge drain on your phone's battery, which could conceivably make your battery more susceptible to overheating.  From my understanding the risks are all more or less negligible.  But when it comes to air transportation, better to err on the side of caution, I suppose.

[Kbb]

Your aircraft has the potential at anytime, due to route or if diverted from planned route, to cross over an international time zone.  The use of an airborne cellphone "may" interfere with the flux capacitor getting the necessary 1.21 gigawatts of electricity during such crossing.  Especially if the plane is traveling in excess of 88 miles per hour.  Otherwise you would be unable to jump ahead or behind an hour after said crossing.

[westg]

1 hour ago, Fuzz said:

I stand a hair taller...

[Arctic Dude]

I work in a hospital and for a long time cell phones were restricted to use in certain areas due to the possible risk of interference with sensitive life saving equipment.  After a number of studies, it was concluded that the only way that a cell phone could interfere with any equipment would be if one were to take their phone and smash it against the equipment!   

I believe that if there was any chance that a cell phone could interfere with the workings of an aircraft, they would be completely forbidden from having in the cabin.  

[luv2fly]

Not to my knowledge.  I was on short final, ILS, poor wx when my phone rang.  Forgot to turn it off.  It was on the entire flight. The look and laughter from the Capt and jumpseater was priceless.

 

[Puros Y Vino]

No real basis behind the claim.  After certain altitudes, they won't work. Period.  Some potential for interference with radio communications exists.  It's probably touted as a line to keep distractions down during takeoff and landings where the cells are still in range.  Ever been on a bus or subway train with numerous people chatting on their phones loudly?  It's far more annoying stuck in a flying tube.   My guess is that its a BS line to keep passengers alert during the two most precarious stages of a flight.

[NSXCIGAR]

8 hours ago, PapaDisco said:

Now, I was sitting in the pilot's seat of course, right next to the radios and pretty close to the antennas.  In a big commercial aircraft you won't be anywhere near the cockpit, but you might be close to one of the antennas.  And someone may argue that current phones are more reliable . . . (can you say "Samsung Galaxy 7??"  ), but me, I turn my phone the f*ck off when on a plane.

There appears to be a significant difference between private and commercial equipment and avionics and from what I can gather modern commercial aircraft are much less susceptible to this kind of EM interference, with the one caveat being those aircraft running 1984-spec equipment which EM interference from cell phones has only been shown to "exceed safety levels". Again, I cannot find any reports of any incidents in modern aircraft due to any electronic devices since the 1999 727 incident, and as well all know cell phones are left on by passengers all the time.

Considering the lack of any evidence of any significant interference in the entire airline industry since 1999, and there having been somewhere around 200 million commercial flights in that time just in the US, let alone the world which if added would likely be well over one billion commercial flights over 18 years with not one report of interference, let alone a serious incident, I would estimate the likelihood of a cell phone's EM interference actually bringing down an aircraft at over 1 in several trillion. No worries.