From the how-gullible-do-you-think-I-am? file comes this item: I was on a commercial flight last month when, after the cabin door was dogged down, a flight attendant announced that her cabin detector showed that four iPhones, three Droids and a iPad were still turned on. Yeah, right. Step back here to seat 26A and I’ll show you my Secret Decoder Ring.Google it, and you’ll other flight attendants are pulling this silly trick.I don’t know if you’ve noticed and I don’t know when it happened, but now airlines are insisting cellphones be turned off, not just placed in airplane mode. Does this suggest cellphone and tablets are really a more serious risk than we thought? Or is it just some sort of corporate kneejerk over reaction to the explosive proliferation of personal electronic devices? Beats me.But let’s explore the other side of this odd little coin. Airlines are beginning to rely on tablets as plate readers and flight libraries and I happen to know of two instances when an iPad or two has been used to bail an airplane out of extremis. One happened in an airliner, the other in a bizjet. We had direct communications with the parties involved.Incident one occurred in August on a westbound United Boeing 767 from San Francisco to Hawaii. A pilot-trained passenger happened to notice that three hours out, the airplane made a slow 180-degree turn back toward the west coast. Shortly thereafter, a PA from the flight deck said that the aircraft had lost all navigational capability. The crew had declared an emergency, climbed to 34,500 feet for additional separation and was aiming for California. It eventually was assigned a hard altitude and landed in San Francisco without incident. As far as I know, the incident didn’t make it into the news cycle. Our correspondent told us she spoke to the crew, who said they navigated home with a whiskey compass and an iPad…in a multi-million dollar airplane with a half-million dollar glass panel. All the better reason to keep a basic text on your iPad refreshing your memory of northerly compass turning error.Incident two occurred a few weeks later. A bizjet inbound to a northeastern airport in good weather lost the entire panel, evidently due to data corruption in jet’s EFIS suite. Once again, an iPad was pressed into service and the jet landed safely, soon to have its brains reloaded. These are two such incidents that I happened to hear about because the people involved contacted us. I wonder if it happens more than we know? (I found a couple in the ASRS database, but not everything is reported, I’m sure.)Regardless, the disconnect here is glaring. On the one hand, use of smartphones and tablets-even a lousy Kindle-is tamped down in the cabin, meanwhile, the very same devices are saving the airplane’s bacon in the cockpit. Do ya think it’s time for a little more meaningful research on this? With electrically controlled everything, modern airliners may be more susceptible to stray EMF than ever, at least in theory. But what’s the reality? And does anyone even know?I can say one thing for sure: Glass may be a lot less bulletproof than we think.