4 ms·

This is strictly anecdotal evidence, but I'll throw in my 2 cents here. I have a private pilot certificate and am working toward an instrument rating right now,

This is strictly anecdotal evidence, but I'll throw in my 2 cents here. I have a private pilot certificate and am working toward an instrument rating right now, which involves being in continuous contact with air traffic control, flying in low / zero visibility conditions, and relying on aircraft instruments to guide me on landings. On numerous(if not all), I've had my iPhone with me, switched on and even in my lap at times(to use the stopwatch). Occasionally I would keep it in airplane mode on extended flights, but only to conserve battery life. Despite incoming calls and SMSs during these flights, not once have any of the instruments been affected by the phone. We can all agree that a four-seater Cessna and 767 are very different, but for nav/comm they all use the same instrument systems. I would find it very hard to believe that a larger aircraft wouldn't have more shielding / protection than a simple Cessna with a phone that's just two feet away. One more thought: Federal Aviation Regulation 121.306 states that no portable electronic devices are allowed except for: portable voice recorders, hearing aids, heart pacemakers, and electric shavers. How are the first and last any different from a phone in airplane mode?

a-priori 16y ago
We can all agree that a four-seater Cessna and 767 are very different, but for nav/comm they all use the same instrument systems. Unlike a Cessna, a 767 has a fly-by-wire system supported by a data bus (e.g. ARINC-429) running the length of the aircraft, often close to the passenger cabin. Presumably, GSM/CDMA signals could interfere with this.
- artmageddon 16y ago
  I'll admit that I wasn't aware of this, but on the same token, would that portion of the electronics not be shielded as well?
  - joezydeco 16y ago
    The 767 was first built in 1981, long before everyone in the passenger cabin was emitting microwave-class RF radiation. The plane itself serves as a very large shield to outside radiation, but I'm guessing the internal wiring is not RF-shielded because of weight concerns. Wonder how much it costs to rewire a 30 year-old plane.
    - bl4k 16y ago
      It cost $368 Million when the FAA forced operators to replace Mylar insulation (cause of at least two accidents): http://findarticles.com/p/articles/mi_m0UBT/is_10_19/ai_n12941245/ http://findarticles.com/p/articles/mi_m0UBT/is_10_19/ai_n129... According to this very interesting IEEE article, it costs anywhere from $1-5M per airplane, which doesn't include lost business cost: http://spectrum.ieee.org/aerospace/aviation/down-to-the-wire/0 http://spectrum.ieee.org/aerospace/aviation/down-to-the-wire...
- borism 16y ago
  767 doesn't have fly by wire - 777 was the first passenger Boeing to get it. But it does have a lot of wiring.
jerf 16y ago
I've had my cell phone on during a commercial flight before. I had it off on the first leg, turned in on to call my wife during a layover, then forgotten I had done so when they asked me to turn the cell phones off on the second leg because mentally it still was off. Given the number of flights I have been on (not all that many) and assuming I'm not particularly more or less likely to have this happen than anybody else (I'm feeling comfortably average here), and given the number of cell phones on a flight, I rather suspect that the average commercial flight of a big plane has at least one cell phone on for the duration with probability approaching 1. Make of that what you will. My point is mostly that the odds that this debate are entirely academic and in fact flights routinely fly with cell phones on are in fact very good.
proee 16y ago
"Despite incoming calls and SMSs during these flights, not once have any of the instruments been affected by the phone." Without a fixed reference you have no way to verify this statement. Even if you crossed reference your flight instrument data with a ground-based reference it would not account for intermittent errors that could occur.
- artmageddon 16y ago
  Can you clarify what you mean by a fixed reference and a ground-based reference? They sound the same to me, although for the latter I believe you may be talking about a VORTAC or other radio-based ground station, as opposed to pilotage(looking outside and seeing the ground).

a-priori 16y ago

We can all agree that a four-seater Cessna and 767 are very different, but for nav/comm they all use the same instrument systems. Unlike a Cessna, a 767 has a fly-by-wire system supported by a data bus (e.g. ARINC-429) running the length of the aircraft, often close to the passenger cabin. Presumably, GSM/CDMA signals could interfere with this.

artmageddon 16y ago
I'll admit that I wasn't aware of this, but on the same token, would that portion of the electronics not be shielded as well?
- joezydeco 16y ago
  The 767 was first built in 1981, long before everyone in the passenger cabin was emitting microwave-class RF radiation. The plane itself serves as a very large shield to outside radiation, but I'm guessing the internal wiring is not RF-shielded because of weight concerns. Wonder how much it costs to rewire a 30 year-old plane.
  - bl4k 16y ago
    It cost $368 Million when the FAA forced operators to replace Mylar insulation (cause of at least two accidents): http://findarticles.com/p/articles/mi_m0UBT/is_10_19/ai_n12941245/ http://findarticles.com/p/articles/mi_m0UBT/is_10_19/ai_n129... According to this very interesting IEEE article, it costs anywhere from $1-5M per airplane, which doesn't include lost business cost: http://spectrum.ieee.org/aerospace/aviation/down-to-the-wire/0 http://spectrum.ieee.org/aerospace/aviation/down-to-the-wire...
borism 16y ago
767 doesn't have fly by wire - 777 was the first passenger Boeing to get it. But it does have a lot of wiring.

jerf 16y ago

I've had my cell phone on during a commercial flight before. I had it off on the first leg, turned in on to call my wife during a layover, then forgotten I had done so when they asked me to turn the cell phones off on the second leg because mentally it still was off. Given the number of flights I have been on (not all that many) and assuming I'm not particularly more or less likely to have this happen than anybody else (I'm feeling comfortably average here), and given the number of cell phones on a flight, I rather suspect that the average commercial flight of a big plane has at least one cell phone on for the duration with probability approaching 1. Make of that what you will. My point is mostly that the odds that this debate are entirely academic and in fact flights routinely fly with cell phones on are in fact very good.

proee 16y ago

"Despite incoming calls and SMSs during these flights, not once have any of the instruments been affected by the phone." Without a fixed reference you have no way to verify this statement. Even if you crossed reference your flight instrument data with a ground-based reference it would not account for intermittent errors that could occur.

artmageddon 16y ago
Can you clarify what you mean by a fixed reference and a ground-based reference? They sound the same to me, although for the latter I believe you may be talking about a VORTAC or other radio-based ground station, as opposed to pilotage(looking outside and seeing the ground).