[cmdahler]

Originally Posted by kovidgoyal

Soon enough cars are going to have as much electronic equipment as planes. Auto drivers, traction control, electric motors and computers to control all this, along with radios and antennas so the cars can call home automatically. I wonder how they're going to deal with cell phones in cars.

But of course, if your cell phone causes your car's engine to stall, that's not such a big deal as a problem with an airplane a few hundred feet off the ground flying at 200 mph...

Also considering that planes fly at high altitudes they are exposed to a lot of cosmic radiation, I remember reading somewhere that a single flight exposes its passengers to the equivalent of n X-ray scans.

Cosmic radiation can be a problem depending on where you are. The pilot and flight attendant unions have all conducted their own studies of this issue and have concluded that, on average, a crewmember flying a typical full schedule that consists entirely of transatlantic or transpacific flying receives the equivalent of approximately one chest X-ray a month. Flying domestically, especially short flights that don't get very high, not nearly so much. Cosmic radiation levels dramatically increase above about 30,000 feet, and the farther north you fly, the worse the radiation gets.

I don't know enough (and googling seems to indicate no else does either) to comment on whether today's airliners are really vulnerable to electronic devices or not. But it seems pretty clear that there is no fundamental reason they cannot be designed to not be.

No one knows the answer: that's basically the problem in a nutshell. There have been a few incidents over the past few decades where some fairly minor problem on the airplane seemed to be caused by a passenger's electronic device. In one particular incident, a passenger's laptop being switched on seemed to cause the airplane's autopilot to disengage. The crew had the guy turn the laptop on and off two or three times, and each time it was turned on, the autopilot disconnected. The crew reported this, of course, and Boeing even went so far as to buy this guy's laptop from him, took the same airplane on the same route with the same laptop in the same seat, and they were unable to duplicate the problem.

Reports like that from presumably reliable witnesses (the flight crew) that cannot be repeated under test conditions drive the regulatory agencies nuts. And of course, it's one thing to cause an autopilot to disengage at cruise altitude: just push the button and reconnect it, or of course the pilot can just manually fly the airplane. But when visibility is down to just a few hundred meters at the airport and the autopilot is required to fly the approach and even make the landing because the pilots cannot see out the window, it would not be a very good time to have the thing randomly disconnect because someone's toy radiated in just the wrong way at just the wrong time.

Without being able to isolate a specific cause for these rare, random events, the regulatory agencies always err on the side of caution. Everyone ought to actually be thankful that the FAA in the U.S. didn't just blanket-prohibit everything electronic from being used on the airplane at all times; they at least had the common sense to limit electronic devices to non-critical phases of flight. It wouldn't have surprised me in the least to see everything prohibited at all times.

All of you folks who are complaining about this are quite right: your reader wouldn't cause any problems...probably. Almost certainly. But without being able to prove to the regulatory agencies that it could not possibly cause a problem during a critical moment, well, can you imagine a government bureaucrat going out on a limb and letting you use it without a mountain of evidence to cover his own backside? As long as there's a random incident or two out there once every ten years or so that no one can reproduce under test conditions, I guarantee that electronic thingy won't be allowed.