Educated Guesswork

Actually, it's a standards issue; the FAA will now allow the picocell installation to be certified avionics, which means there is no more safety issue since certified gear is tested for cross-compatibility with everything else on the plane. Of course, if the plane is not fitted, there's still the usual problem.

The certification issue was first bridged for Boeing's 802.11 system for airliners.

The 9/11 report indicates that passengers were using cellular phones on flight 93 (the one that crashed into the field). It is arguable that the 9/11 attacks stopped being effective *during the attacks* because the passengers of flight 93 had tactical awareness about what had happened already, and part of that was through the use of cellular phones.

I like to think that in addition to the current assinine security theater and pointless privacy violations, there are actually effective changes being made in the name of "homeland security", which might be a possible explanation. Perhaps I have too much faith...

Andrew:

What usual problem? There's basically no reason to believe that modern cellular phones *ever* presented a safety problem. They didn't work that well without the picocell but that's a different issue. And just because it doesn't work well is no reason to ban something...

So, again:
What conditions are likely to get the FCC to lift the ban?

What's changed to make lifting the ban attractive now?

Air marshals, IIRC. The feds want to be able to use cellphones in the air, and they (wisely, IMO) realized that private enterprise could provide it.

There's basically no reason to believe that modern cellular phones *ever* presented a safety problem.

Indeed; as I often say when I talk with people about this: Would you fly in a plane that would crash if the moron in the seat next to you decided to turn on his cell phone? Do you think the airlines would put such a plane in the air? The whole issue of mobile phones and entertainment equipment being a safety problem has always been hooey.

It's not a safety concern per se, but cellphones really do interfere with avionics. I have first hand experience of this flying light aircraft, where it is a severe annoyance to forget to turn off a cellphone and then have very loud interference in your headset for the whole flight.

More critically, they interfere with ILS systems. Again, it's annoying, and several times airliners have been forced to go missed approach and go hold while the crew find the offending cellphone. It's a problem for operations, rather than safety, although theoretically one could switch on a bunch of cellphones together during a Cat-III approach and cause a serious problem; however, the crew will still be able to go missed approach. It's not as bad as, for example, a serious electrical problem at the same point in the approach.

Well, light aircraft are clearly different, so let's skip that.

I've certainly heard stories of commercial aircraft (mostly with old avionics) reacting badly to cell phones but I've never seen it demonstrated in well-controlled studies. That said, if it's really a problem, it's the planes that need fixing. I suspect it would be quite trivial to build--and get on a plane--a radio transmitter with much more power than a cell phone.