Cell Phones and Air Safety

Cutie Pi writes "On the heels of this recent Slashdot story discussing Wi-Fi use on airplanes, the BBC is reporting about new evidence indicating that cell phones can interfere with airplanes' navigation systems. From the article: "In tests, compasses froze or overshot, navigation bearings were inaccurate and there was interference on radio channels." Look like like Wi-Fi and airplanes just don't mix."

Comments

Aren't they already banned?

[cascino]

Aren't cellphones already banned on commerical airliners?

Our Rights.......... /.

[jortega]

Wireless I really cannot believe that 802.11b can affect telecommunication equipment in an airplane with all that shielded cable. This could be a start to restricting use of our airwaves. JV

ok some dumb questions..

[zogger]

...if it's all this bad, why don't planes fall out of the sky from all the existing thousands of cell phone towers all broadcasting, and tv and radio stations and other sorts of radio wave emitting places? Why not? Is it *really* that bad, or is this FUD? Seems like if it was really that bad we would have seen mass crashes and various huge numbers of fubars by now, yes?

I am skeptical, but readily admit I don't know.

Re:Um...

[GMC-jimmy]

...new evidence indicating that cell phones can interfere with airplanes' navigation systems.

This isn't anything "new". We've known about this since the 80's.

Most, if not all, consumer electronic devices intended for 2-way communication (ie. cell phones) emit RF.
RF is bad for avionics.

Re:compass?

[Anonymous Coward]

Pinecone and Seaweed for meterology.
At night they use stars too. On landing they have little man with table tennis bats guiding them in.

Notice how the staff sit facing the REAR of the plan , yet the rest of the cattle sit forwards? Why? Rear facing is safer.

JUST DONT ASK, about CAPTON wiring on planes (boeing especially), Its BANNED from military planes yet alowed on commercial. WHy? It is the cause of many electrical faults and failures. Starts fires too.

Still like flying? There are more scary stories, air recirculation for one. Hypoxia, TB? More.

35??

[c1pher]

"Since 1996, pilots have reported 35 mobile phone-related safety incidents, including false warnings in the cockpit, distractions causing aircraft to stray accidentally onto runways or fly at the wrong altitude, interrupted radio communications and multiple safety systems malfunctions."

35 cases in 7 years?? How many planes fly each day??

Difference between "VFR" and "IFR"

[Maxwell'sSilverLART]

The navigation instruments in question are extremely sensitive; that precision is required when operating in the terminal area (particularly on the approach) in clouds or other visual obstruction. Operating in such conditions is done under Instrument Flight Rules (IFR). Particularly in the terminal area, IFR operations depend on precision, with less error tolerated the closer the airplane is to landing. On final approach (200' above the ground, 1/4 mile from the touchdown zone, moving at 150 knots, for a typical airliner; some approaches can be flown entirely by instrument, without ever seeing the ground, all the way to touchdown), precision is very important; a very small error could have significant consequences.

Navigating from city-to-city is usually done with the aid of instruments regardless of conditions, but doesn't require quite so much precision--consider that, in trying to find New York, you're looking for a target several hundred square miles in area. A half-mile here or there is irrelevant.

How did they hit the buildings? Well, if you saw any video at all of any of the crashes, you might have noticed the color of the sky: blue. As in, no clouds. Without clouds or other visual obstructions, operations can be carried out under Visual Flight Rules (VFR). In short, the terrorists steered the airplanes toward the targets that they could see, visually, from many miles out!

Duh.

How about GPS?

[SirPhreak]

I've always wanted to take my GPS on a plane and check out to see if the pilot is speaking the truth when announcing the altitude, plus checking speed would be cool. Anyone the rules about a GPS on a plane?

Re:Physics

[Maxwell'sSilverLART]

DME, VOR and ILS are based on ancient technology.

I believe you meant to say "DME, VOR and ILS are based on ancient technology that is well-proven and works.

Seriously, the reason the ILS hasn't changed in half a century is that it has a wide installation base (so changes would affect hundreds of thousands of airplanes around the world). We have a technology with incredible inertia; lots of people use it, and it is ungodly-expensive to replace avionics. (Nav/Comm radio? $2K for a nice one. GPS? Try $10K for some of the nicer models, equivalent to what you find in nicer cars these days. And that's in the light aviation market--radios in jets start closer to fifty grand apiece, and most airplanes have three or four comms, three or four nav radios, GPS, etc.) Changing technology requires exhaustive testing to gain certification, and an enormous investment from all parties; if a new system is going to "take off" (pun intended), it will have to be available in a wide area, or else nobody will want to pay for it.

The ILS has seen some incremental improvements; standard (Category I) ILS typically guides the airplane down to 200' above ground level (AGL). Cat II ILS, which requires special equipment on the ground and in the air, and special pilot training, reduces that to 100' AGL. Cat III ILs (which is actually subdivided into IIIa, IIIb, and IIIc), can provide guidance all the way down to the runway, in zero-zero conditions (zero foot cloud ceiling, zero foot forward visibility). The technology is proven reliable, relatively simple (always nice), and has the capability to go to zero-zero; what more do you really want from it?

VOR is "good enough" for most purposes; it has a nominal accuracy of four degrees (if memory serves), which is only four miles' error when you're sixty miles from the station. In most parts of the US, you would be hard-pressed to get more than sixty miles from a station. Four miles' error may sound like a lot, but it's really quite inconsequential--all of the other airplanes on VOR are seeing the same error, so it's a simple transposition, and you're in controlled airspace anyway, with a guy watching a radar screen to keep an eye on things. On top of that, the absolute error decreases as you approach the station. Given that most VORs are either on or near airports, the problem takes care of itself; as you get close to the airport (where precision is more important), the error decreases. Distance Measuring Equipment (DME) is plenty accurate at low altitude[0], and at high altitude, errors are less critical; on top of that, when using DME, everything is referenced to DME readings, so again, it's a transposition error. As long as everybody's on the same page, it's not a concern.

If you really need that degree of positional accuracy, there's GPS, which is being adopted with great enthusiasm by the aviation community. If you need more precision, use WAAS/LAAS, or inertial nav, or all of the above into a flight management system; if you need that kind of precision, though, you're probably referencing yourself to something specific on the ground. If that's the case, there's a wonderful navigation technology that can give you all kinds of precision. It's called "eyeballs."

Voice (and other stuff) is done using AM instead of FM because AM has lower power requirements for equivalent service; less power means less weight in the airplane, and better service for the ground station. Jam-resistant modulation? Again, we run into the problem of paying for the upgrade (unless, of course, you're offering), testing (and lots of it), and the fact that we have no real need. If we get into a situation where we're in that much trouble, the civilian fleet will no doubt be grounded (again!), and the military already has encrypted, jam-resistant communications and navigation technology. What we really need is more bandwidth, and we're getting that by reducing the channel spacing (comm channels have gone from 50kHz to 25kHz, and are moving to 8.33kHz)

It's mostly GSM that's at fault.

[Chmarr]

I'm a recreational pilot, and I've had first-hand experience with mobile phone that interfere with the avionics on a light aircraft. I've not witnessed any issues with nagivation instruments being affected, but I've certainly had interference on the communication systems (radio) from the mobile phone, when, for example, I've forgotten to turn my own mobile phone off (quickly remedied, thankfully :)

However, it's mostly GSM phones that are the problem. When the phone detects that it's losing contact with the cell, it makes a short burst of very high energy transmissions that, on the radio, sound like 'dt-dt-dt dt-dt-dt dt-dt-dt' (morse code for SSS? :). It's very annoying.

However, I've NEVER noticed this with a CDMA (okay, technically IS-95) phones, which are a lot more common in the USA (vs England and Australia which primarily use GSM now). So, the UK's test is probably more accurate for GSM phones. However, I'm also sure it's not a black/white issue, but rather a matter of proportions.

Personally, if *I* was in charge of the safety of a passenger-carrying flight, I'd want to make damn sure there wasn't ANYTHING that could adversely affect navigation, even if the chance was remote. Flying around IFR at night is /scarey/ :)

Further studies need to be done. Operators need to weigh the costs of shielding the navigation instruments against the benefit of allowing passengers to use bluetooth/WiFi on the aircraft. And, passengers need to damn well obey flight crew instructions :)

So what happens if the plane flys near an storm?

[schappim]

If the navigational instruments are so sensitive, why are they not being effected by the masses of static electricity being created on the wings as air molecules brush pass and create a electromagnetic field?!? Please don't tell me that Wifi would cause a greater effect then 40m of polarised wing span... -Marcus www.digitalive.com.au

Re:Doesn't make sense

[ColaMan]

The pilots can certainly tell though. I was on a singapore air flight last year - as we were beginning taxiing, the pilot hits the brakes and says, "Whoever's using that mobile phone, turn it off - NOW. Crew, search the cabin." This was (I kid you not) less than 45 seconds after the Captain had specifically said that phones were not to be used. WTF? Did someone think "Oh, my phone's not allowed to be used? Better ring the office to tell them!"

So yes, they can tell if there's a operating cellphone on board. Maybe they have a little red light marked "Cellphone in Use" on their panel. Certainly seems to piss them off though.