I recently bought a laptop with Microsoft Maps & Trips software. Among other things, this has a GPS receiver.

For amusement (no other real reason) I attach the GPS to the window if I have a window seat. I'd used it on DL and CO with no objections, but on an AA flight last week, the FA told me it was prohibited. Sure enough, it's mentioned in the in-flight mag.

I haven't used it on NW yet. Anyone know anything about NW rules? Not that it's a big deal. It's not like I'm going to book NW if I can use it but not otherwise.

Hello,

GPS units may be used on NWA. On the ground and above 10,000 feet
It is only NWA's policy, not an F.A.R. It is a little confusing when one airline says yes to something and another says no to the same thing.

Flight Attendant Manual 120.8.5

Doesn't SouthWest specifically call out that GPSs are ok?

Yes, that adds to confusion.

Steve B.

Okay mabe a dumb question - but what do you do with a GPS at 30K feet?

Track your physical location, in 3 dimensions.

I can't remember how many times I've red-eyed, and wondered what the town was I was flying over. I'd like it even more if I knew the path (and what side of a big city we were going to be on) so I could shift seats to watch a city go by. I've seen Chicago from cruise altitiude on a clear night during a red-eye, and it was amazing.

Steve B.

I'll concur with what NWAFA says. In the NWA pilot's Flight Operation Manual, there is a list of prohibited items. GPS is not an item on that list. Some flight crews are a bit naive about the operation of GPS and as such, will error on the conservative side and ask that it not be used.

A GPS unit is a receive only device and does not transmit any signal which would possibly interfere with electronics on the aircraft.

Several pilots use them....more as a hobby than anything else. I've seen some that didn't work properly on an aircraft. A couple of years ago, there were 'marine versions' which were designed for nautical use, and as such they were designed to work on a platform going 10 knots, not 500 knots. Not sure if that's a problem with the newer systems out there today.....

Enjoy......

Being receive only is not a guarantee of no emissions. Many types of receivers, especially those using heterodyne circuitry, emit in the process of receiving.

That's why no TV's or radios are allowed to be used.

Whether these signals cause ( or can) problems is another matter, but a 'receive only' device is not necessarily totally passive.

On several occasions I've heard FA's on NWA specifically include GPS on their list of prohibited items.... but it seemed like a freelance.

Has 'Mythbusters' dealt with this subject yet? I'd like to see that. I'm incredulous that a laptop with all wifi/bluetooth disengaged could cause a 757's navigation systems to crap out. Maybe this has already been discussed ad nauseum.

Check out this article from USA Today about the use of GPS devices on board: http://www.usatoday.com/travel/colum...-captain_x.htm

There is an interesting link in the article that lists the various airline policies.

Not with computer or GPS, but they tested cell phones, and found no effect on a modern jet's systems.

Cell phones are banned due to an FCC issue with their use....not an FAA issue. The real issue with cell phones is that they 'communicate' with cell towers that are within line of sight. At 40,000 feet, with thousands of cell phones talking with hundreds, or thousands, of towers, it would absolutely overwhelm the phone networks.....Hence the FCC restriction.

Let's hope cell phone use on aircraft never comes to fruition. After landing tonight in EWR, the entire aircraft got to listen to 'loud Sally' telling her buddy all about our flight, what she's having for dinner (soup), etc. etc. Absolutely painful..........

I thought the line of sight distance the cell phones can reach is about 3 miles at furthest which is about 15000 ft. That's why there is a tower about every 3 miles on the highway. If this is correct, how can the cell phone signal inside an aircraft at 40000 ft reach the towers on the ground? Could someone please enlighten me as to what distance the cell phone signals reach? Thanks.

HJ

Intersting...makes sense, but the explanation you always hear is that the interfer with the nav/ground nav syestem(s). I agree with you that allowing cell phone use in flight would allow a bunch of idiots with no manners/ettiquette to ruin things for others, but I'm of the school that we need straight explanations for things--if it's an FCC reg, don't have the FAs announce that it's due to interference with the nav system!

It's the curvature of the earth.
Think "Line of Sight" literally. If you put a bright tennis ball on the top of a 100ft tall cell tower and started walking away (and assume ou have "unlimited eyesight" & no obstructions to block your view other than the ground ) you would eventually lose sight of the ball. You get lower and lower due to the earth's curve until the ground between you and the ball blocks your view. Digging in the back of my feeble mind, I seem to recall that sailors out on the open water can't see a bouy more than 2 miles away for the same reason ... so your quote of 3 miles for a tower seems right.

In a plane, your "line of sight" to see that ball goes a long ways out !!

It's kinda the same for radio waves .. you must be in the "line of sight" for a decent reception. There are some other factors. Ironically, the older, lower "AM Radio" frequencies tend to follow the ground (I forget the explanation) thus the "ham radio" hobby of listening to broadcasts from far away. I know that aircraft navigation (VOR - the predesessor to GPS and/or Inertial Navigation as the primary system on short/mid range aircraft) is very "line of sight" and its frequency range picks up where FM Radio leaves off. This proximity of frequencies is what started the "no radios or TVs" inflight rule awhile back.

IMHO ... you and I may have the interest to know such details, but most of the travelling public (and probably a lot of crew members) don't know 'why' and could care less. Bottom line ... if it's prohibited it's prohibited. The FAA reg of no radios or TVs has been around forever so most folks probably assume all electronics fall into the same category. Even if the Flight Attendant knew the difference, it's still easier to give the same reason for all devices. As for requireing the announcements to include "these are prohibited due to FAA and these due to FCC" ... the on-board announcements are already so drawn out and mundane that no-body ever listens ( why doesn't the FAA realize this ). Besides, the exchange for such trivial knowledge is what FlyerTalk is for