This was an answer to a question in another thread.

As I answer this, please keep in mind that I am NOT an electrical engineer. There may be some electronic issues that I do not know about or understand. Remember that this is only my opinion.

I’ve been with my airline since 1984, and have only had one time where I suspected any sort of navigational interference from a portable electronic device.

That was in the early 90’s where we had some fluctuation and loss of signal of the ground based navigational aid that were using. We found there was a passenger using a portable video player. Those were not authorized for use at that time. It couldn’t be determined whether that was the cause of it or if it was a coincidence. We found out that he had been using it after we had the problem and then were past that navigation aid. (It was a VOR nav aid, which are used less and less now that GPS is so prevalent.)

There was also a landing incident at ORD a few years ago during a low-visibility autopilot approach. The 727 rapidly nosed-over and hit just before the runway. A dramatic grab by the Captain saved this from becoming a huge disaster.

The cause for the nose-down glide path command or signal to nose-over was never determined. However, the investigators spent quite a bit of time checking out all the industrial buildings in the area looking for sources of “radio interference” signals. They also check all the cell phone records of the passengers to see if someone was making a call.

Part of the problem with determining the cause of an incident like this is that they can never accurately re-create any electronic signals that could cause a problem.

Of course, technology is always improving. The FAA also is usually very slow to allow new devices or change the restrictions. They want to be sure first and no one wants the liability.

Let’s say a “friend of mine” tried this…

While flying the plane on autopilot and with the other pilot carefully checking everything. He turned on his cell phone in flight to see if anything would happen.
The phone didn’t work because it said there was “no signal”. They were over a major city.

I asked someone about this and the answer I got was that when a phone receives signals from multiple towers at the same time, it doesn’t know which to use and gives that error message.

With the talk of now allowing cell phones in flight, I assume that issue has been resolved.

Personally, as an online junkie, (I have one web site and am working on two others), I know that passengers would enjoy and benefit from being able to go online while in flight. In fact, it would take discipline on my part to not go online while working.

Cell phone conversations are another matter and could easily disturb other passengers. Imagine planning on catching a much-needed nap in flight and having the person in the seat next to you gabbing loudly on the phone the entire time.

Before I do an automatic landing in zero visibility in Europe after flying all night, if cell phone use is allowed in-flight, I want the complete assurance that there is absolutely no way that the can be any interference.

Therefore, I hope it comes eventually, but I hope that the proper research and restrictions are all in place first.

Pilot Paul