Electronics off on Planes??

VaSteve · 08-11-2005, 05:27 PM

I have been doing a bunch of travelling this summer. They always say to turn off electronics like my ipod. One time I accidentally left my cell phone on the whole trip (I'm still here). The last flight I heard someone else's ringing while they were asleep.

Why do I have to turn it off? Does it really affect t he navigation systems? If it was that important wouldn't they MAKE me turn it off?

What do you all do/think?

dhoward · dhoward's Garage

Maybe anything that deliberately transmits a signal.
I once had a F/A tell me not to use my digital camera.
I believe the FAA has in the past, purchased consumer electronics from PAX when they thought the device was compromising A/C systems, but were unable to duplicate the suspected effects....

Brother · 08-11-2005, 05:36 PM

Yes it can, but it probably won't with this generation of stuff. Proposed frequency emmissions from future electronic devices might have a more severe effect on navigation equipment.

I've sat three feet from the avionics in a small jet that I'm flying with no effect.

Apparently there have been some problems with inertial navigation system alignments before, but it is not a huge problem. However, unlike the highway, you can't just pull over and fix it.

Joeaksa · 05:47 PM

Like Brother said, the current generation of cell phones nomally should not cause any problems. Their filters and transmitters are much better than the earlier generation.

I usually sit in the cockpit and realize that my cell phone is still on sometime around 30 minutes after takeoff and we are level at 39,000. Considering that the phone is 2 feet from the instruments and not 100 in the rear like the pax, any issue would have show up and fast.

I have worked for McDonnell Douglas, Boeing and Bombardier. Everyone of these companies builds airplanes for the military and during the testing they bombard the planes with loads and loads of radio wave and radar radiation to simulate their being in combat. No problems with them at this time so doubt that one or two cell phones or blackberry is going to cause any problems.

Course you need to realize that this is all about money, (not safety) and its the money that the airlines get from the in-flight telephone calls. When they figure a way to make money off of cell phones then it will become legal...

JoeA

David · David's Garage

I heard they're talking about allowing cell phone use on planes. I also heard from a less reliable source that the problem is not with the plane's electronics, it's with the phones hunting back and forth with cell towers.

campbellcj · 07:26 PM

I heard the same thing as David, that the cell phone rule was mainly a phone company effort to reduce high-speed cell-hopping. No clue if this is true, but I find it VERY hard to believe that your normal, FCC approved consumer electronics would interfere with either commercial or military comm or avionics systems.

Think about it -- much of the earth is plastered with high-powered cell, RF, microwave, and every other imaginable kind of transmitters across a huge frequency spectrum. The plane is flying thru a sea of 'noise' on your whole trip. And a piddly little milliwatt handheld gizmo is gonna make a difference? I'm no EE but it sounds like a crock to me.

Dantilla · 08-11-2005, 07:45 PM

As a private pilot, I called the FAA. They said it's because it screws up the cell phone company.

So I called the cell phone company. They said it screws up the FAA's stuff.

Bottom line is they both said no.

LeeH · 08-11-2005, 09:04 PM

My wife point out that she hears digital noise over her headset when someone has left their cell phone on... sort of what you might hear when you use your cordless phone near a cell phone or a wireless router. Dangerous? Nah, but she said it's distracting to be on final approach and hear the ticking in her ears. She'll make a p.a. announcement for the passengers to check their cell phones and the interference usually goes away.

ischmitz · ischmitz's Garage

Lufthansa now offers 802.1 based WiFi on their longhauls while other airlines ask you to turn off your WLAN adapter....

MFAFF · 08-11-2005, 10:40 PM

From ehat's been written the issue is two fold..

1) The phone mast distribution is designed and built to deal with vehicle based phones.. so spacing and speed of hand over from one cell to another is tailored for those speeds.
Going up and faster means that the phone can in theory be equidistant to tow or more masts (cells ) at a time hence using up more capacity than a gorund level reciever....thus whilst you are only making one call the network has to deal with it as two or three or whatever, hence they are losing money....

2) Mutual interference between phones and aircraft systems. You're right that planes are bombarded with all sorts of RF emissions and all sorts of combinations during testing and certification. However they cannot test every possible combo and possibility. So rather than take a risk that a 1 in 10 million combo may detract from a system a blanket ban is applied.

The use of cell phones (and internet) is being made possible by installing a cell on the plane that then uses a sat link to a ground station to link all the calls and internet demands.....that way the transmission is 'controlled' in that it goes from phone to aircraft mounted mast (ignoring all others) and from there via a tested sat link (nice money spinner there) to the gorund...

Learnt all this whilst getting a sat phone installed on the jet....

VaSteve · 08-12-2005, 03:28 AM

Actually, it wasn't my cellphone I was concerned about. I really want to use my ipod from gate to gate. The noise cancelling headphones really help out on the engine noise. So much so that I have taken to leaving them "on" even with the ipod off to cut the noise.

Joeaksa · 08-12-2005, 03:36 AM

Quote:

Originally posted by LeeH
My wife point out that she hears digital noise over her headset when someone has left their cell phone on... sort of what you might hear when you use your cordless phone near a cell phone or a wireless router. Dangerous? Nah, but she said it's distracting to be on final approach and hear the ticking in her ears. She'll make a p.a. announcement for the passengers to check their cell phones and the interference usually goes away.

We get the same thing and thats usually what makes me realize that I have forgotten to turn the phone off.

We also used to have the first series of blackberries receive emails at altitudes up to 30,000 feet. Now that I have a newer one it stops picking up emails at about 10,000 feet.

JoeA

304065 · 08-12-2005, 05:00 AM

Well, I could go into the whole local oscillator thing and radio/heterodyne theory. We could talk about the base frequency of DME, ACARS, Radio Altimeters and scalloping needles. We could discuss the max radiative power from a bullet antenna in close proximity to the aircraft's fuselage VHF mast.

But none of that would be true.

The real reason you can't use cellphones on airplanes IS safety-related.

It's so we don't CHOKE THE LIVING ***** out of the PASSENGER NEXT TO US who talks on his cell phone ALL THE WAY FROM JFK TO LAX!

Dantilla · 08-12-2005, 07:31 AM

We have a winner!!!

Thank you John Cramer!

Tim Polzin · 08-12-2005, 09:22 AM

Quote:

Originally posted by john_cramer
It's so we don't CHOKE THE LIVING ***** out of the PASSENGER NEXT TO US who talks on his cell phone ALL THE WAY FROM JFK TO LAX!

Amen!

Tim

Joeaksa · 08-12-2005, 11:03 AM

Can we transfer this concept to the "ersatz valley girl" sitting next to us at lunch or dinner the next time it happens? You know, the one with a cell phone glued to her face who will not shut up?!

Course there is the "young up and coming" exec, a 22 year old guy who is doing the same thing at the other table and who needs everyone within earshot to hear of his latest girlfriend or toy...

Personally I like the device the Israeli's developed that shuts down all cell phone calls within a 100 meter circle. Too bad its illegal here in the states...

JoeA

304065 · 08-12-2005, 11:48 AM

Quote:

Originally posted by Joeaksa

Personally I like the device the Israeli's developed that shuts down all cell phone calls within a 100 meter circle. Too bad its illegal here in the states...

JoeA

What's that, a daisy-cutter?

Unfortunately the only place one can go these days where cellphone use is absolutely prohibited and stigmatized is a private club.

campbellcj · 08-12-2005, 06:13 PM

LOL, John is exactly on the money! I am absolutely opposed to phone use on planes. I already can't stand the gabby friggen passengers or the obnioxious drunks or the screamin' kids. Noise cancelling headphones help cut out the white noise (drone) but not the voices, as much.

I would however possibly even pay a bit to have data access. Flights would go soooo much quicker with broadband! (I'll be flying ~11 hrs this weekend...hate it)