use of electronic devices during Flight
 

A question to the pilots here... do electronic devices such as cell phones and CD players really interfere with a flight?

I remember reading once, a long time ago...that because CD players operate at 44.1kHz, they can interfere with the communications system of the airline.

So what is the real story on this?

This guy in the link below was a jerk about it:
http://www.dallasnews.com/sharedcontent/dws/bus/stories/051308dnmetpassenger.f2feb5b0.html?npc&nTar=OPUR

mythbusters tested it. Cell phones don't do squat. Mythbusters did get one particular frequency to cause a problem, but I think it was an unusual freq and at much, much higher power than a regular cell phone can xmit.

It's a precaution, and really, would you prefer they were over cautious when you're in a plane or would you prefer them to throw caution to the wind?

mythbusters tested it. Cell phones don't do squat. Mythbusters did get one particular frequency to cause a problem, but I think it was an unusual freq and at much, much higher power than a regular cell phone can xmit.

It's a precaution, and really, would you prefer they were over cautious when you're in a plane or would you prefer them to throw caution to the wind?

i have no problem with the rules...just wondering...
i like Mythbusters, especially the one about the Ice Bullet

I've heard the ban on cellphones during flight was actually something pushed for by the cellular companies. Supposedly it was too difficult to keep track of the roaming issue whilest up in a plane, so that would have thrown off their billing practices. Don't know if that's true or not, but as mentioned above, apparently it doesn't interfere with actual pilot-ground communications. Admittedly, it's also nice not to be stuck next to a cellphone yakker for 6 hours straight. Don't know about the rest of the electronic devices and their purported interference, though.

I just read somewhere recently that one airline (British Airways, I think?) is now permitting cellphone and wireless (i.e. blackberry) usage during flights. I don't particularly care about calls, but having access to email and internet would sure be nice.

Heard something similar. But the angle was a plane is traveling so fast that calls would switch towers faster than the system can handle.

They don't cause problems. I use a cell phone from time to time in a plane (private) and nothing happens. If you are cruising at 30,000 + feet, the cell phone would not get a signal, so it has nothing to do with cell towers. Many years ago, it was possible to flood all the towers in an area, making it very hard for others to use the system.

I really wonder what the truth is on this matter; I will conjecture due to carelessness, forgetfulness or just being ornery on any given flight there are several cell phones, computers, Ipods, electronic games etc. left on by accident or on purpose. The aircraft can't possibly be that vulnerable to the emissions from these devices otherwise we wouldn't be allowed to board with them. I suspect something happened to the nav system or autopilot on an obsolescent aircraft when someone played a Walkman in first class; there was an overreaction and now we have the electronic equivalent of "no swimming for an hour after you've eaten otherwise you'll get cramps and drown."

I'm a pilot, and called the FAA about this-

They said it's a no-no because it screws up the cell phone companies.

So I called my cell phone company-

They said it's a no-no because it screws up the FAA's stuff.

Bottom line, to get approval to use anything in/around airplanes is difficult. Even though cell phones do not interfere with any of my avionics, it has not been proven to the satisfaction of the FAA that it couldn't, under any circumstance, cause interferance, thus it stays illegal.

Not worth all the hoops to jump through. Lots easier just to say "don't do it."

I imagine the Radio Technical Commission for Aeronautics (RTCA) is the right group to consult to get the official technical position held by the FAA on this matter. Mythbusters are amateurs.

Jim, you have to think about aggregate level of radio frequency emissions from many passengers using their personal electronic devices in the various phases of flight. I seem to recall that this has been studied in great detail by RTCA. I don't recall the punch line. :)

Phones come in handy when your radio takes a *****, I did have to dial up the tower once so I guess they are ok to use, they didn't have a problem with it..

That's also technically an emergency and the pilot in command has the authority to deviate from any regulation or rule to the extent necessary to deal with that emergency.

You may have however violated other parts of the Federal Regulations falling under the jurisdiction of other agencies (FCC, etc.) but far as the FAA is concerned, you're covered.

I seriously hope you filed an ASRS report for that.

Craig, the original question was related to use of these devices on a commercial airliner. You situation is different, as we all know you're too old to even see your instruments (do you even have more than one?), much less worry about your cell phone throwing them off. :p :p :p

Wayne's on to it. We were always told it was an issue with the cell towers and it would only take a few large planes with everyone talking to overload the system. I can also vouch for the "they won't work above +/- 30,000 ft theory. I've tried many times. Your battery also dies really fast when the phone has to search for a signal all the time.

That's what I've read, too. The proposed solution is to install a re-transmitter on the plane that would accept the signal & focus it to specific local towers passing underneath.

The day is coming & the joy of plane travel :o will suffer because of it.

Ian

I don't know if they cause interference but I really hope they are never allowed for a couple of reasons,

first, it is the only time I can have some peace and quiet from my phone and blackberry. I actually cherish my 8-9 hr flights as a refuge from data overload and

second, I could not stand the noise level in the cabin with tens of people yapping away. Not even my high tech Sony noise cancelling in ear headsets and Ipod could muffle.

From Wiki Mobile phones on aircraft

"A few U.S. airlines have announced plans to allow mobile phones to be used on aircraft, pending approval by the FCC and the FAA. The method is similar to that used in some cars on the German ICE train: the aircraft will contain a device known as a picocell. It will act as a miniature mobile telephone tower, communicating with mobile phones within the aircraft, and relaying the signals to either satellites or a terrestrial-based system. The picocell will be designed and maintained for full compatibility with the rest of the on-board avionics. Communication between the picocell and the rest of the telephone network will be on separate frequencies that do not interfere with either the cellular system or the aircraft's avionics, much like the on-board phone systems already aboard many commercial aircraft. Since the picocell's antennas within the aircraft would be very close to the passengers and inside the aircraft's metal shell both the picocell's and the phones' output power could be reduced to very low levels, reducing the chance for interference. Such systems have been tested on a few flights within the United States, under waiver from the FCC.

ARINC and Telenor have formed a joint venture company to offer such a service on board commercial aircraft. The mobile phone calls are routed via satellite to the ground network and an on-board EMI screening system stops the cellphones contacting the ground network.

These systems are comparatively easy to implement for customers in most of the world, where GSM phones operating on either of just two bands are the norm. The multitude of incompatible mobile phone systems in the United States and other countries makes the situation more difficult — it is not clear if the onboard repeaters will be compatible with all of the different cell-phone protocols (TDMA, GSM, CDMA, iDen) and their respective providers.

On 30 August 2006, the Irish low-cost airline Ryanair announced it will introduce a facility to allow passengers to use their mobile phones in-flight.

As of mid April 2007 Qantas have teamed up with Panasonic Avionics Corporation and AeroMobile to commence a three month trial that will "enable customers to send and receive e-mails, access the Internet and send and receive text messages from their own mobile phone"

On 18 October 2007 Ofcom published proposals for the technical and authorisation approach that would be adopted to allow this for European GSM users on the 1800Mz band on UK registered aircraft.

On 20 March 2008, Emirates Airline flights began allowing voice calls in-flight on some commercial airline flights.

The approval by EASA of these systems has established that GSM phones on certified aircraft types are considered safe to use when installed with a on-board cellular picocell.

On 26 March 2008 Ofcom approved the use of mobile phone-supporting picocells aboard aircraft in the United Kingdom. Airline companies will have to equip the aircraft with picocells and apply for licenses."

Ian

As any beginner pilot knows, VHF and UHF are line of sight. From an elevation of 1000 feet you can see many, many towers. This is the reason-- from FL 350 cruise you could lock up many towers on the same frequency.

Also, every radio uses a "local oscillator" to compare the received signal to- these cause RF emissions. Do you really want to see what happens if the pilots happen to be shooting an ILS Cat III into the fog?

The REAL reason is safety related but not in the way you might think. Standards of etiquette being what they are, the cellphone ban avoids the hundreds of potential episodes of choking the living beejaysus out of your fellow passenger who jabbers on a cellphone ALL THE WAY FROM NEW YORK TO LOS ANGELES

Way it was explained to me (when I was working at a wireless phone company) was that all the towers that can "see" the phone arbitrate to decide who has the best signal, and when to hand off.

Not such a big deal when you're driving up the freeway @ 55 MPH and two or maybe three towers are involved, but significant when you can "see" a 100 towers or more, and are moving @ 600 knots to boot, and then multiply that by 50+ phones on the aircraft...

If there's effectively a tower on the aircraft, it's a slam dunk for the phone, it only talks to that...

Heck yes. It's bad enough that no airline provides a "no children" area, much less service. Yet.

I love children, but I couldn't eat a whole one...

W.C. Fields, Excellent!

Your kidding right?

I used to love flying, but between the pointless airport NAZI security and the seats shrinking every year as if we wouldn't notice our knees pressed to the seat in front and elbows jabbing me in the side all the way across the country and the new lack of in flight service I would hardly call it a "joy" anymore.

http://forums.pelicanparts.com/uploa...1210710844.jpg

Yeah. I'm kidding. Last year was a record for me . . . over 50 hours of flight delays . . .

Ian

A few points. The newer cell phones have far less power and have a tougher time reaching the ground (range issues),

About 20 years ago I have friend who worked installing the in-flight phones. Had a conversation with one of the company bosses. He essentially stated that they were going to lobby to get cell phones banned from commercial flights as it would cut into their profits.

I honestly can’t see how they are a safety issue. I have seen lots of -130 flights with multiple devices going and no safety related problems.

S/F, FOG

If cell phones worked and were allowed, I'd really be ticked to be sitting next to someone for hours on end while they yak'ed on the phone the whole time!

I actually have had a cell phone cause an issue on a flight. Up front we wear headsets and much like the radio in your car they can occasionally pick up a loud clipping sound from the cell phone. It tends to happen when the phone is sending/receiving (calls or texts) or when it is searching for a tower.

Let me tell you if you think it's irritating in the car try it with the speaker half an inch from your ear. I have actually asked passengers in flight to check their cell phones because the noise was interfering with our communication. Other than that, no cell phones don't cause the wings to fall off. No I don't want to sit next to someone on their phone telling a buddy all about their last colonoscopy.

We can often hear when one of the pilots have forgotten to shut off their cell phone. When they transmit on the radio you can hear the clipping in the background.

Not that it's ever happened to me ;) but that is the first thing I check.

We have instances of ground based cel phone use causing interference too!
We had a couple of towers moved to eliminate the problem.......

Rudderboost, you a controller?

Cheers

this thead turned out to be an interesting read...thanx to every one of you guys with true experience in the aviation industry that shed some light on this.

The frequency spectrum for cellular phone use is way up in the UHF band, above 800 Mhz. The spectrum assigned to ATC is in the VHF range between 108 - 132 Mhz. Because of the selectivity requirements in the communication equipment, there is very little chance for a cell phone to interfere with ATC communication. There can be harmonic affects, however, that might explain some of the clicking described by a pilot earlier.

Well Industry Canada are the ones that determined that to be one of the causes, we have also had instance where we could here the actuall call. Not sure what may cause that too happen or cause the interference but it could be because some of our VHF is paired with UHF but now where near 800......

No, I'm on the other side of the radio in the air. :) If your a controller in the B.C. area I bet I've talked to you a couple of times!

Upon further thought, that may not have been the interference they found, it may have been a tv station.

Rudderboost, I am a Vancouver Terminal controller, who do you fly for?

Cheers

Same here. We can tell up front when someone in the back has a phone left on. To tell the truth its not much of a bother other that this damm chirping.

Rudderboost,

We would never forget to turn our cell phones off up front. Never... well that is after we did once and it ran the battery down all the way searching for a signal from Boston over the Atlantic to Istanbul... :)

man you pilots fascinate me with what you do... flying rockets really. If i could do it all over again, i would have taken the advice of that Navy recruiter back in 87 who promised me that based on my perfect test score...he would "make me Top Gun"... I guess the pull of the blonde on the back of Cruise's motorcycle wasnt enough to sway me though. :rolleyes: In another life perhaps.

Regarding control to plane communications, I remember being on a flight about 5 years ago during a major winter storm, where we couldnt land in Detroit so they were trying to figure out where to put all the planes and they directed us towards Minnesota... the communication was on the stereo system on the seats and I happened to tune in to hear the controllers talking to all of the pilots...at one point it got heated up with frustrated pilots demanding their instructions, people talking over each other etc...so the controller shut everyone up by saying 'listen, no one will speak unless we address them specifically...understand??" so everyone shut up and they were able to get things organized...that was a frank and fantastic listening experience for a person on that plane that night.

Just because comm is VHF doesn't mean it can't hurt. What about DME?

An internationally standardized navigation system which allows an aircraft to measure its distance from a selected ground-based beacon. Such beacons are used throughout the world by all airliners, most of the military aircraft of the West, and a large number of general-aviation aircraft. The range of service is line-of-sight up to 300 mi (480 km) and system accuracy is usually 0.1 mi (0.16 km) but precision equipment, intended for use during landing, has accuracy of 100 ft (30 m).

The airborne equipment, called an interrrogator, transmits pulses of 1 kW peak power on 1 of 126 frequencies. These are in the 1025–1150-MHz band and are spaced 1 MHz apart. Each pulse is of 3.5 microseconds duration and is paired with another, spaced 12 or 36 microseconds later. The combination of frequencies and pulse spacings therefore provides 252 operating channels.

The beacon on the ground, called a transponder, receives these pulses, delays them by 50 μs, and then retransmits them, usually with a power of 1 kW, on 252 frequencies lying between 962 and 1213 MHz. The pulse-pair spacing is 12 μs on those frequencies not used by the interrogator, and 30 μs on those frequencies shared with the interrogator. The transponder transmission is called the reply. The frequency difference between interrogation and reply is always 63 MHz. This arrangement allows each transmitter frequency to act as the local oscillator for its associated superheterodyne receiver, the intermediate frequency of which is 63 MHz. For landing purposes, some transponders have powers as low as 100 W.

In the aircraft the replies to its own interrogations are recognized by their phase coherence with their own transmissions, and by the elapsed time measured between transmissions and reception (minus the 50-μs transponder delay), usually by means of a crystal clock. This elapsed time is about 12 μs for each nautical mile (7 μs for each kilometer), and is displayed in the cockpit on a digital meter, which is usually calibrated in miles and tenths of miles. See also Electronic navigation systems; Instrument landing system (ILS).

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