Cell phones and commercial aviation - Mythbusters

[Greebo]

I just read this on another forum in which I participate:

Aside from that, cellphones SHOULD still be off. I saw a Mythbusters the other night that proved that a number of cell phone frequencies can still interrupt aircraft instrumentation. For the planes that are very new and have all the shielded, digital instrumentation, it doesn't, but for anything older, with unshielded wiring or analog instrumentation, it can seriously mess with it.

Did anyone here see the Mythbusters in question?

I'm gonna have to check and see if the TiVo grabbed it.

 

[wsuffa]

Chuck, I did not see it.

However, in a former life I was part of the international committee (ITU SG-12/2) that worked on aviation-other radio compatibility (a fancy way of saying "interference"). Some radios and some equipment is more susceptible than others - at the time, some of the high-end radios performed more poorly than some of the lower end stuff. The FAA was opposed to requiring reject filters on the aviation equipment, preferring to ban anything that might interfere. The FCC had the position that the interference was not nearly as bad as the FAA made it out to be, else planes would be falling out of the sky every day. This was pre-cellphone days... at the time, the interference sources included broadcast transmitters on the ground, two-way radios, home TV receiver amplifiers, cable systems, and the like.

Not to minimize the issue, but I'm sure you can find cases where interference is caused, and a lot of cases where there is no interference. From personal experience, in my plane, I've often left the cellphone on (receive only, and purely by accident of course), and noted no interference as a result.

Speaking of mythbusters, one of the episodes on Saturday night was verifying the pictures of the sliced airplane... they rigged an aircraft engine on a platform and ran the engine & prop into a fixed aircraft fuselage. Sliced like a spiral-cut ham. Worth watching.

 

[Greebo]

I saw that one - they saved the slice up for the very end, of course - thankfully TiVo let me skip the buildup and see the actual destruction. WAY cool.

 

[inav8r]

I did see the episode and I enjoyed it. Basically they bought some used radios and mocked up a small plane and found that if they hooked it up with unshielded cables and used a cell phone bench tester they could make the needles on a VOR jump all over the place.

They then tried to replicate the experiment by taking the mocked up plane out to a park near SFO and drove around the parking lot while trying to keep the ILS needles centered (unsuccessfully). They finally just stopped and repeated the experiment with the same results.

They then went over to the airport and got in a nice business jet (I don't remember what, sorry) and repeated the experiments and found that no matter how much wattage they output on the cell phone bench tester they could not interfere with any of the electronics in a modern aircraft.

They basically summarized up by saying that a cell phone can NOT take down an airliner as the equipment has to be shielded and is installed in such a way that it can't be interfered with (at least by a cell phone). They then went on to say that the FAA can't allow cell phone operations in a plane because in order to do so they'd have to test every phone / device combination and that would just be too expensive - so it's just cheaper and more efficient to ban them altogether.

 

[wsuffa]

I saw that one - they saved the slice up for the very end, of course - thankfully TiVo let me skip the buildup and see the actual destruction. WAY cool.

Actually, the buildup was interesting, too... they had to call the mechanics to get the airplane engine running...

 

[Let'sgoflying!]

I saw parts of it and 'what Mike said'. I would have liked them to take the cell phones all over the airplane and try incoming and outgoing calls, hold it up to the walls where the wires might run, in the cockpit etc.... seemed like he just stayed in one seat during the tests.

 

[poadeleted20]

They then went on to say that the FAA can't allow cell phone operations in a plane because in order to do so they'd have to test every phone / device combination and that would just be too expensive - so it's just cheaper and more efficient to ban them altogether.

Since the FAA does not ban cell phone operations in airplanes altogether, that's bogus. It's the FCC, not the FAA, which imposes that ban. The FAA cell phone ban affects only air carriers, not Part 91, where the PIC could permit cell phone use if the FCC did not prohibit it.

 

[inav8r]

Since the FAA does not ban cell phone operations in airplanes altogether, that's bogus. It's the FCC, not the FAA, which imposes that ban. The FAA cell phone ban affects only air carriers, not Part 91, where the PIC could permit cell phone use if the FCC did not prohibit it.

Thanks for pointing that out.

To be quite honest I don't remember where they said FAA vs FCC but I do remember that both organizations were mentioned. I deleted the show off my DVR already so someone else will have to clarify any mistakes I made in reference to what actually aired on the show.

 

[JRitt]

Thanks for pointing that out.

To be quite honest I don't remember where they said FAA vs FCC but I do remember that both organizations were mentioned. I deleted the show off my DVR already so someone else will have to clarify any mistakes I made in reference to what actually aired on the show.

I watch the episode. They did say FAA and they also said that that it was illegal for the small planes to use a cell phone.
In their mock up cabin the only interference was obtained at the 800-900mhz freg. range. They tested all of the known ranges in the real plane and boosted the output power of the cell phone, had a large ant. on the transmitter and had no problems

 

[SkyHog]

Since the FAA does not ban cell phone operations in airplanes altogether, that's bogus. It's the FCC, not the FAA, which imposes that ban. The FAA cell phone ban affects only air carriers, not Part 91, where the PIC could permit cell phone use if the FCC did not prohibit it.

Isn't there something, either IFR or Part 135 or something that required Cell Phones be turned off in flight also?

I seem to remember something that the FAA banned with cell phones in specific conditions.

But i could be remembering incorrectly

 

[wsuffa]

Nick, the rule is IFR the PIC must determine that any electronics devices will not interfere with the operation of the equipment required for IFR flight (paraphrasing because I'm in the middle of doing taxes...)

 

[poadeleted20]

Isn't there something, either IFR or Part 135 or something that required Cell Phones be turned off in flight also?

I can't find anything specific in Part 135 on cell phones in particular or portable electronic devices in general (wasn't much of a problem when I was flying 135 over 25 years ago). I believe the only rule that applies to 135 ops (unless something is added to the individual operator's ops specs) is 91.21, the one about PIC approval and non-interference with aircraft systems.

 

[Ghery]

I can't find anything specific in Part 135 on cell phones in particular or portable electronic devices in general (wasn't much of a problem when I was flying 135 over 25 years ago). I believe the only rule that applies to 135 ops (unless something is added to the individual operator's ops specs) is 91.21, the one about PIC approval and non-interference with aircraft systems.

I just did a quick check on the GPO's web site where they have all the CFRs and found three PED references beyond 91.21 -

121.306
125.204
and
135.144

They all look about the same.