Bluetooth on an Airplane? 145
bblazer asks: "Since I travel quite a lot, I am very familiar with the warnings about cell phone use on an airplane (could be bunk, but I still respect it and those around me). But what about using Bluetooth? I just got off an Alaska Airlines flight where the flight attendant said that we were not permitted to use any device that sends or receives a radio signal. I often use the bluetooth features of my PowerBook and Treo while onboard a plane (you can have the Treo on without having the cell phone on), or I set up a mini-network with others I may be traveling with. Could Bluetooth cause any problems, or is this something I need not worry about?"
Shouldn't affect anything (Score:4, Informative)
dude, the law doesn't care if it is true or false (Score:5, Informative)
Issue one is that airplanes move through cells too fast for most cellphones to deal with it, and that causes them to ramp up their RF signal strength and the frequency of their outbound conenction traffic in an attempt to maintain a conenction to the network. (cell phones weren't allowed on transports but our UHF, SHF, and VHF radios worked fine)
Issue two is that avionics packages are not always shielded to spec in older airframes and there is the outside chance that 'something' could go wrong. (just like the outside chance that 'something' could go wrong at the gas pump) (military airframes are emissions shielded by guys who make the tinfoil hat brigade look sane)
The technical problems are exaserbated by the social problems - namely that there isn't a lot of significant science on the validity of the fears, that there are issues of profit to be had by airlines for 'owning' connectivity onto and off of a plane in flight, and that the technology landscape is a too fluid for the legislative response to be valid. Add to this the blanket of "security" as a catch all excuse for anything feasable but hard, and you begin to get a real picture of the situation that results in the "no transmitters" rule.
The bottom line is that, while there may be no compelling technical reason to ban transmitters (my opinion) no one wants to be responsible for making the call and then have an NTSB report come back naming cell phones as the cause of a airline crash.
Until that changes, it is illegal, just like replicating digital instances of copyrighted material, carrying a disposable lighter or wooden matches through security, making jokes about something being "da bomb", asking to see the regulations on presenting ID at the gate, or telling your less geeky pal how to defeat the ROT-13 encryption on his e-book.
Turn off your wifi and bluetooth before you get on the plane.
Re:Semi-qualified opinion (Score:5, Informative)
Re:No FAA restriction of any kind... (Score:3, Informative)
If you look at the regs, pretty much all of the places it's referenced, you can see this exception to any restrictions:
(5) Any other portable electronic device that the operator of the aircraft has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used.
It's commonly perceived as an FAA restriction since the public only sees "faa people" i.e. flight crew - enforcing it, but the underlying restriction is done by the FCC.
Where it really sucks is that currently, even though it's perfectly safe, I can't use my cell phone in my own aircraft. That is on it's way to being changed, but unfortunately, what is likely to happen is that the big-money telecoms will get the rule changes worded in such a way as to only allow commercially provided aviation cell phone services, instead of a generic change.
Re:Yes it could cause problems. (Score:5, Informative)
The only instruments that require RF are navigation. Not used all that much at takeoff. Also all standard navigation instruments are VHF except GPS. Even if your GPS failed 100% the pilot would then use INS and or VOR/DME. As too a cell phone messing with FBW. If that ever happened the designer should be shot. A FBW system is well shielded from almost all RF if not then a good lightning strike or sunspots.
Frankly the story about the cell phone I find iffy at best. It might have happened back in the day of analog phones and it might have caused interference with a VOR or comm radio. Any worry about interference would have nothing to do with navigation it would have to do with interfereing with plane to tower communications. The pilot really need to keep in touch with the tower during take off an landings a garbled transmition could cause a near miss or worse.
Your bluetooth uses 2.4ghz and is so low power that you really do not need to worry about it. BUT they are so touchy these days I would shut it off just to avoid going to jail.
Real info from a pilot. (Score:5, Informative)
I'm an FAA certificated private pilot of several years. I work in the aviation industry and have had some interesting experiences with this exact issue.
I do not know that, or pretend to know that operating any RF devices will "crash" an aircraft.
I DO know that even leaving a cell phone on during flight can interfere with avionics and communications. This is from real experience - and it was *very* distracting.
Here's the story: Flying closed traffic touch & goes at Oakland International Airport, my instructor (CFII) and I were both hearing a loud static noise at two places in the pattern. This was pretty darn distracting to say the least. Here we are, doing proficiency drills (landings / pattern / emergency landing without power, etc) and there's a darn buzzer in our ear shortly after takeoff and at midfield. What was it? I had left my cellphone on accidentally and buried deep in my flight bag. It was soo annoying that I asked my instructor to fly the plane while I akwardly tried to twist around the seat of the C172 and find the cell, and only was able to after several painful moments - but it was worth it for how annoying the buzzing was.
Now, this was a Day VFR (visual flight rules) flight under nearly ideal conditions. Most major aviation accidents that occur have some level of human factors that play into the incident. Further, the NTSB establishes a "chain of events" that leads up to the accident - any one of which being broken would likely have prevented the accident.
Let me ask you this. You are cruising at night in IFR conditions (in the clouds, no horizon) 30,000 feet in a commercial aircraft and the pilot loses his artificial horizon. Immediately, the pilot informs the copilot and the copilot starts flying the aircraft on his 'good' instrument. You land safely. This exact scenario was one of the more recent fatal airliner accidents in Asia, except that the pilot was distracted and did not properly give control to the copilot.
Do you want the pilot of your aircraft to be distracted by frequent buzzing in his/her headset? Aircraft these days have the capability of flying and landing themselves. Pilots are largely there for two reasons (IMHO). One of these is to re-assure the public. The other, perhaps more valid, is to deal with emergency situations. Please - don't mess with them, once the autopilot is disabled/off, they're your only chance.
Re:Yes it could cause problems. (Score:4, Informative)
Interference and model jets [jetpilots.org] Ironic?
2002 CAA Omega interference PDF [caa.co.uk]
Did Personal Electronic Devices(PEDs) cause TWA 800 to explode?? [aviationtoday.com]
US House Commitee [house.gov]
2001 NASA Report PDF [nasa.gov]
2002 NASA Report PDF [nasa.gov]
I never could find the FAA listing of aircraft incidents. It showed several cases of problems with avionics that the cockpit crew attributed to PEDs
Re:It's all FUD (Score:4, Informative)
A quick stroll through the ASRS database [faa.gov], searching on "RF Interference" or "EMI"
Report # 541518
DEPARTING SFO WE WERE ADVISED THAT ATC WAS NOT RECEIVING OUR TRANSPONDER. THE ATC FAIL LIGHT WAS ON AS WELL AS NUMEROUS TCASII FAULT MESSAGES. WE SWITCHED TO TRANSPONDER NO 2 AS PER THE OPERATING MANUAL AND ATC WAS ABLE TO RECEIVE IT. THE AIRPLANE HAD ONLY ONE MODE S TRANSPONDER SO WE HAD NO TCASII AT THIS POINT. THE FLT CONTINUED NORMALLY FOR ANOTHER HR OR SO WITH NO CHANGE IN THE STATUS OF THE NUMBER 1 TRANSPONDER AND TCASII. IT WAS AT THIS POINT THAT I DISCOVERED THAT I HAD INADVERTENTLY LEFT MY PCS PHONE ON. AND THAT IT WAS IN SEARCH MODE. I TURNED IT OFF. IMMEDIATELY, ATC NO 1 AND TCAS WERE RESTORED TO FULL FUNCTIONALITY. NO FURTHER ANOMALIES WERE OBSERVED DURING THE FLT.
Report # 536654
NAV INTERFERENCE. OVER CHT, CLRED '10 DEGS R INTERCEPT LOC RWY 31L PLAN CIRCLE RWY 22L.' UPON TUNING LOC FREQ AND SETTING COURSE, IT APPEARED WE WERE ON THE LOC, ALTHOUGH VISUALLY WE APPEARED S OF COURSE. ATC ASKED IF WE HAD INTERCEPTED AND SAID WE WERE S OF COURSE. THE CDI THEN SWUNG FULL SCALE TO THE OTHER SIDE INDICATING WE WERE N OF COURSE. I TURNED TO CTR THE CDI AND WE SWITCHED TO TWR. MY CDI SWUNG R INDICATING WE WERE S OF COURSE. I NOTICED THE FO'S CDI WAS SWINGING THE SAME DIRECTION AS MINE, BUT MOVING ABOUT HALF AS FAR. WHEN WE SAW THE RWY, WE WERE N OF COURSE WITH CDI'S INDICATING WE WERE S OF COURSE. WE WERE HIGH AND WELL N OF COURSE WHEN TWR ASKED IF WE COULD GET DOWN FROM THERE. WE ASKED TO BE TURNED OUT TO RE-ENTER THE PATTERN. UPON TURNING OUTBOUND WE MADE A PA ASKING PEOPLE TO PLEASE MAKE SURE THEIR CELL PHONES AND OTHER EQUIP WERE TURNED OFF. THE CDI'S IMMEDIATELY BECAME STEADY AND WE COMPLETED A NORMAL ILS RWY 31C CIRCLE RWY 22L WITH NORMAL INDICATIONS AND THE FLT ATTENDANTS RPTED THAT A WOMAN IN THE FORWARD LOUNGE WAS TALKING ON HER CELL PHONE. AS SOON AS SHE TURNED HER PHONE OFF, OUR CDI INDICATED NORMALLY.
Report # 283948
CLBING THROUGH 13000 FT MSL, RADIO ALTIMETER INDICATED 900 FT. GPWS SOUNDED 'TOO LOW TERRAIN.' THIS WARNING CONTINUED FOR SEVERAL MINS. HAD FLT ATTENDANT CHK CABIN FOR ELECTRONIC DEVICES. PAX WAS FOUND WITH CELLULAR PHONE 'ON' BUT NOT IN USE. PAX SHUT OFF CELLULAR PHONE AND PROB STOPPED. NO FURTHER PROBS DURING REST OF FLT OR RETURN LEG (ORD-LGA-ORD).
Perhaps you'll understand this explanation... (Score:4, Informative)
Have you ever driven a car that, at a certain speed or on a certian road, the car got *very* loud, and all you had to do was speed up or slow down to dampen the noise?
The first example has to do with reflection. The second has to do with resonance.
In a flying tin can you cannot possibly know where the reflections and resonance will occur. You do not know what equipment may or may not be affected by your transmissions.
While holding your cell phone next to an avionics box may have no effect, sitting in seat J23 with the cellphone in your pocket as it broadcasts at maximum power (because, see, you're in a tin can) may be just the spot to form a nice reflection which, coupled with a resonance, would put a very strong signal right at the wrong spot of an important piece of equipment.
Your blue tooth has the same problem, though the frequencies are difference, and the power *should* be less. This doesn't actually make it any less dangerous, however.
The plane you are riding in is likely very old. The equipment can easily be more than 20 years old, and if the equipment itself isn't, the design is.
The long and short of it is: Planes are a bad place to use equipment that intentionally radiates (ie, transmits). They aren't so great for devices that unintentionaly radiate either.
While "testing" does take place there is no way to ensure that everything will operate properly in real conditions - only a complete design analysis could come close to providing that information.
-Adam
Re:Yes it could cause problems. (Score:1, Informative)