5 ms·

> After a few more days it simply ignored the flight mode and connected to get fresh ads. Worrying. "Flight" mode exists for a reason and should not be overrid

> After a few more days it simply ignored the flight mode and connected to get fresh ads. Worrying. "Flight" mode exists for a reason and should not be overridden.

arcticbull 7y ago
Flight mode exists because the FAA applies unsafe-until-proven-safe methodology to everything flight related (as they should). If flight mode mattered at all planes would be falling out of the sky on the regular, many people just leave their phones on the whole trip. The only reason I turn my phone off is because it wastes a lot of battery as it tries to manage tower hopping the whole time. Planes are getting blasted by RF in the cellular bands continuously from the ground, too, so this is taken into consideration in the design process. Don't get me wrong the Kindle shouldn't do what it's doing but it's by no means a safety issue.
- jacquesm 7y ago
  > Planes are getting blasted by RF in the cellular bands continuously from the ground, too, so this is taken into consideration in the design process. It's a totally different affair if you are receiving a signal by a 100 Watt transmitter at 10 Km or a signal from a 1 Watt transmitter at 5 meters distance. The 1 Watt transmitter will overpower anything in its band with great ease and any dirt on the spectral output will have the same effect in other bands. Note that most cellphones will crank up their output if they can't connect to a base station that they can receive. Of course plane designers will still do what they can to reduce this nuisance but leaving our phone on makes it harder than it should be. Please turn your phone off or to airplane mode and consider it a very small price to pay for flying an airplane. Yes, flight mode does matter, no it probably won't crash a plane but does it have to before you would consider following a very simple rule?
- derefr 7y ago
  IIRC there isn't a problem for most of the flight; but right as you're ascending/descending your phone can end up getting a very weak line-of-sight connection to a whole bunch of cell towers at once, which causes a few different problems, but all of which come down to "it makes both your phone, and all the towers, shout really loudly at one-another to try to achieve a circuit." Which, sure, means that there might be EM interference (on bands ATC doesn't even use, but which the pilots might like to switch to in event of emergency.) But, more importantly, it puts your phone's radio through an unusual high-power-draw situation that the phone's manufacturer may not have bothered testing for, which can make phone batteries explode that might not have otherwise ever exploded. Oh, and also, a plane-load of people whose phones are all ranging hogs circuits on a bunch of towers at once (for no productive purpose, since the phones don't have high-enough SNR to actually communicate anything useful with any of the towers they can "see"), so the cellular service providers have politely asked the FAA to get people to not do that.
  - seehafer 7y ago
    Thanks for this clear explanation of why this rule exists. Never understood it until now.
    - diminoten 7y ago
      I would take his explanation with a hefty grain of salt...
      - arcticbull 7y ago
        Indeed, the reality is that people will leave their phones on intentionally or unintentionally so engineering within aerospace has to, and does, take this into consideration. There's reasons the rule exists, but it doesn't put you at increased risk.
  - shkkmo 7y ago
    I have never seen the claim that cell service providers played an active role in this. Do you have a source for this info? I am curious to learn more.
    - arcticbull 7y ago
      I've heard this claim before but the justification was because the network wasn't designed to cope with someone hopping from tower to tower every few seconds. No citation here either. The handoff must be a total mess.
      - shkkmo 7y ago
        The closest I can find the the 2013 FAA press release about allowing devices to be used during all phases of flight. > The FAA did not consider changing the regulations regarding the use of cell phones for voice communications during flight because the issue is under the jurisdiction of the Federal Communications Commission (FCC). The ARC did recommend that the FAA consult with the Federal Communications Commission (FCC) to review its current rules. So it seems to be the FCC that has made this decision (in consultation with the FAA it sounds like). [0] https://www.faa.gov/news/press_releases/news_story.cfm?newsId=15254 https://www.faa.gov/news/press_releases/news_story.cfm?newsI...
PeterStuer 7y ago
The reasons being (1) you are moving faster than the network hand over protocol is designed for and (2) even if it worked you could be impinging on the juicy margings of in-flight service offers. If airplanes could be brought down by turning on a cellphone you would never have been allowed to travel with one in the first place.

> After a few more days it simply ignored the flight mode and connected to get fresh ads. Worrying. "Flight" mode exists for a reason and should not be overridden.

arcticbull 7y ago

Flight mode exists because the FAA applies unsafe-until-proven-safe methodology to everything flight related (as they should). If flight mode mattered at all planes would be falling out of the sky on the regular, many people just leave their phones on the whole trip. The only reason I turn my phone off is because it wastes a lot of battery as it tries to manage tower hopping the whole time. Planes are getting blasted by RF in the cellular bands continuously from the ground, too, so this is taken into consideration in the design process. Don't get me wrong the Kindle shouldn't do what it's doing but it's by no means a safety issue.

jacquesm 7y ago
> Planes are getting blasted by RF in the cellular bands continuously from the ground, too, so this is taken into consideration in the design process. It's a totally different affair if you are receiving a signal by a 100 Watt transmitter at 10 Km or a signal from a 1 Watt transmitter at 5 meters distance. The 1 Watt transmitter will overpower anything in its band with great ease and any dirt on the spectral output will have the same effect in other bands. Note that most cellphones will crank up their output if they can't connect to a base station that they can receive. Of course plane designers will still do what they can to reduce this nuisance but leaving our phone on makes it harder than it should be. Please turn your phone off or to airplane mode and consider it a very small price to pay for flying an airplane. Yes, flight mode does matter, no it probably won't crash a plane but does it have to before you would consider following a very simple rule?
derefr 7y ago
IIRC there isn't a problem for most of the flight; but right as you're ascending/descending your phone can end up getting a very weak line-of-sight connection to a whole bunch of cell towers at once, which causes a few different problems, but all of which come down to "it makes both your phone, and all the towers, shout really loudly at one-another to try to achieve a circuit." Which, sure, means that there might be EM interference (on bands ATC doesn't even use, but which the pilots might like to switch to in event of emergency.) But, more importantly, it puts your phone's radio through an unusual high-power-draw situation that the phone's manufacturer may not have bothered testing for, which can make phone batteries explode that might not have otherwise ever exploded. Oh, and also, a plane-load of people whose phones are all ranging hogs circuits on a bunch of towers at once (for no productive purpose, since the phones don't have high-enough SNR to actually communicate anything useful with any of the towers they can "see"), so the cellular service providers have politely asked the FAA to get people to not do that.
- seehafer 7y ago
  Thanks for this clear explanation of why this rule exists. Never understood it until now.
  - diminoten 7y ago
    I would take his explanation with a hefty grain of salt...
    - arcticbull 7y ago
      Indeed, the reality is that people will leave their phones on intentionally or unintentionally so engineering within aerospace has to, and does, take this into consideration. There's reasons the rule exists, but it doesn't put you at increased risk.
- shkkmo 7y ago
  I have never seen the claim that cell service providers played an active role in this. Do you have a source for this info? I am curious to learn more.
  - arcticbull 7y ago
    I've heard this claim before but the justification was because the network wasn't designed to cope with someone hopping from tower to tower every few seconds. No citation here either. The handoff must be a total mess.
    - shkkmo 7y ago
      The closest I can find the the 2013 FAA press release about allowing devices to be used during all phases of flight. > The FAA did not consider changing the regulations regarding the use of cell phones for voice communications during flight because the issue is under the jurisdiction of the Federal Communications Commission (FCC). The ARC did recommend that the FAA consult with the Federal Communications Commission (FCC) to review its current rules. So it seems to be the FCC that has made this decision (in consultation with the FAA it sounds like). [0] https://www.faa.gov/news/press_releases/news_story.cfm?newsId=15254 https://www.faa.gov/news/press_releases/news_story.cfm?newsI...

PeterStuer 7y ago

The reasons being (1) you are moving faster than the network hand over protocol is designed for and (2) even if it worked you could be impinging on the juicy margings of in-flight service offers. If airplanes could be brought down by turning on a cellphone you would never have been allowed to travel with one in the first place.