GPS during flight. A question...
 

I understand that several airlines don´t permit the use of GPS systems from passengers during flight for security reasons.
Any one can explain me those reasons? (Interference with the plane´s electronic systems, homeland security, etc.?)

I didn't know it was safety. I figured it was covered under the radio receiver ban.

Welcome to FlyerTalk!

I've only ever heard of the ban with respect to the device being a radio, not a security issue. Anyone claiming that it is a security or FAA rule is lying. Some airlines do permit the use of GPS receivers, so it certainly isn't an FAA/TSA rule at all.

I don't recommend accusing the Flight Attendant of lying about the situation, but they are if they claim it is a security/FAA/TSA issue.

First, welcome to FT!

I do not believe that GPS use is any security risk at all, but that does not mean that airline employees will not claim that it is. They tend to claim that anything is a security risk if they do not want you to do it. I have always understood that the "security" reasons of some airlines against GPS use included that they did not want someone to know exactly where the aircraft was so they could do something nefarious at a particular place/time.

Adding to this, it's also a control and power issue IMO. FAs don't like pax to know what is going on before they hear from the crew and know themselves. Some pilots feel the same way. Pax with a little aviation knowledge and watching a GPS track can get a really good feel for arrival delays (speed restrictions), holding patters, and deviations, let alone diversions. And a little GPS info can blow away the frequent lie that "we'll be landing in a few minutes" when you know the plane is 100 miles from the airport, still over 20K feet, aimed away from the airport, and doing only 250 knots. This control/power reason is also used by some pilots and FAs as a reason to disable audio channel 9 (which pipes air-traffic control to interested pax), though they don't use the terms "power" and "control" when they explain their reason. :)

UA is one of the carriers that explicitly allows passenger GPS, though many FAs and even some cockpit crews don't know it. But I've never been hassled, and I frequently use my little hiking GPS in flight.

There's also some pure paranoia regarding the security risk feeling. Some reports are that 9/11 hijackers used handheld GPS to guide the planes (presumably because they were too clueless about flying to use the plane's own navigation systems, and because the plane's systems aren't designed for aiming at buildings). Therefore in some people's minds, GPS possession by pax, let alone use, is suspicious. To me, that argument makes about as much sense as saying we should ban pencils and paper because bank robbers might use it to write demand notes.

I take the opposite of the conventional "security risk" argument, and claim it is a security enhancement if a few passengers happen to be monitoring their flight on GPS, listening to channel 9, etc. Who knows what might have happened on 9/11 if pax had realized early on that their westbound flight had turned east, their plane was no longer responding to air-traffic control, etc.

I'm not sure of the technology reasons, but I recall seeing GPS receivers being listed as a do-not-use electronic device. A couple years ago, before it was listed, I liked using mine occasionally. I usually had to put it near the window to get a good signal, but it was neat seeing speeds ten times normal.

What airline:confused: It's not a universal "do not use" device, that's for sure. As one of the posters mentioned above, UA explicitly allows them, as does CO. Haven't checked any EU airlines recently but I know several of them do allow their use.

A controversy over this flared up a few months ago. A few "belt-and-suspenders" personalities suggested that the interference with flight systems was a finite possibility, but they were effectively shouted down by the "you don't know what you're talking about - the hell with safety concerns" types.

The reason that some airlines prohibit in-flight electronics is that all the electronic environments under which they are used cannot be modeled accurately, so the ones that DO allow them are basically allowing time bombs having fuses of indeterminate length aboard their aircraft.

i asked a pilot about it--he said it wouldn't interfere with anything on their end. some airlines allow them, some allow them during the above 10K feet restrictions...

A pilot is not the right person to ask.

Find a board of people experienced in aircraft electronics shielding and risk analysis, and base your opinion on their input.

If I'm flying over land, I just look out the window, and I usually have a good idea where I am. (although northern Canada is tough...).

Wirelessly posted (BlackBerry8830/4.2.2 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/105)

The same people who made the rules that electronic devices can never be used and can cause problems are now allowing WiFi on flights. I can assure you that the wire shielding has not changed on the planes between the initial policy and the new one. To suggest that the radio waves can be interfered with because more than one receiver is present is certainly entertaining, but not something that you would be able to document should you try.

The initial ban was because no one knew, and better safe than sorry. Now that there have been years of controlled testing and empirical evidence the old rules are just quaint.

To be VERY clear, there is no FAA/TSA/any other regulatory body rule that says GPS receivers are allowed or prohibited. It is up to the airline to decide using whatever reasoning they choose. If they choose to cite FAA rules they are not being wholly truthful. Everything else is just their perogative.

There are no interference issues, but there are potential security issues. A GPS unit can certainly pre-programmed with the position of a potential "target" and allow a hijacker to fly right to that target. This ability is obviously only possible if cockpit security is breached.

In fact, I have argued that the 9/11 hijackers must have used GPS guidance to hijack planes hundreds of miles from their intended targets and still find them with their very basic piloting skills. I don't care how clear the weather was that day... it would be very difficult to take over a 757 at 35,000 feet over Ohio and fly a virtual straight line to hit the Pentagon without GPS guidance. However, many people disagree with me on this.

A thread from last summer:

http://www.flyertalk.com/forum/showt...t=gps+security

on NW / DL
 

I fly mostly on NW & DL metal.

The DL website specifically states that GPS can be used when other PEDs can be.

The NW website is a bit more vague in that it does not mention GPS specifically.

However, I've used my eTrex Vista Cx on numerous flts, both domestic and international with little or no problems. I did have 1 or 2 FA ask me about it, but nothing more.

If personal electronics (those carried by normal travelers; I'm not talking about portable jammers, portable high-power beacons, etc.) were at all likely to cause crashes or even incidents, a couple of them would occur every few years. On any given commercial flight, there is a high probability that someone's cell phone, ipod, laptop, GPS, etc., is accidentally left on during takeoff/landing.

To my knowledge, there has never been a documentable case of electronics interference. There's a lot of weird things that pilots have reported that end up getting blamed on electronics because there is no other easy explanation. But as you say, pilots generally aren't experts in avionics shielding and risk analysis.

And this is 2008, not 1948. It's not as if the average flight relies solely on an analog AM radio navigation beam that happens to be at the same frequency as the resonant circuit in a portable AM radio. (Not to mention that the power of the RC circuit in an average portable AM radios has shrunk quite a bit over that time. A walkman-sized radio is a lot less likely to cause interference than an older transistor radio, let alone a tube radio) The classic movie scenario of someone hanging a AM radio next to the nav aids and sending the plane off course is not really likely today. Even if it were to occur, I think ATC would get on a commercial pilot's case pretty quick over such a deviation.

My guess is that the people making the rules restricting electronics weren't electrical engineers who specialize in electromagnetics, they were "risk management" types and liability lawyers who are obsessed with having zero-risk instead of minimally-small risk. Probably the same folks who think warning labels are necessary for every commercial product and think that banning water was a sensible move by TSA. :rolleyes: