[QUOTE=emma dog;12930305]AAaaahhhh... another electronics thread.
[QUOTE]AAaaahhh...another thread not airlline specific misposted in the wrong forum.
We will spirit it off to TravelBuzz for participation by all FlyerTalkers not just those who might trip over it in the AAdvantantage forum.

~magic111

No, but the British Civil Aviation authority did and demonstrated a risk of interference.

Citation? Cell phones don't really work while flying. And, assuming that they do, are any modifications made to the plane prior to this?

And, do they allow the use of cell phones during take off and landing?

You realize things like WiFi radios that they're worried about shut down while in sleep mode?

No, nothing has escaped me. I learned the difference betwen nuance and hyperbole a long time ago.

Is it possible the next airplane take over will be done electronically?Seems as if could be done either by something in your check on or in the cargo or perhaps even from a ground station that could cause problems with the A/Cs electronic system

I was very careful to say that electronic equipment radiates unwanted energy, and to avoid speculation about how important it is. The specific point I was implicitly addressing is the equipment as designed (typically a shielded box for a PC) has to meet certain standards by design HOWEVER commercial equipment is not 100% tested in production, PLUS all bets are off as soon as the enclosure has been compromised. There can also be significant amounts of radiation from wires connected to the box, which are not even type tested.

FWIW I'm not as concerned about radiated energy interferring with cockpit equipment so much as I am about it disturbing the various navigational antenna, which are sprinkled all over the outside of the airframe. There's an extra furrow outside AMS which provides ample demonstration of how a faulty radio altimeter can contribute to an accident, and the amounts of energy detected by these instruments, and by the SatNav equipment is so small that it takes relatively little to interfere with them.

The way I see it, the aircraft is most vulnerable as it's preparing to land where the workload is high and the pilots have relatively little scope to react if something goes wrong. From what I know I feel a lot happier if all the unnecessary junk is switched off and stowed for landing, and the FAA seems to feel the same so why do people keep bringing this up time and time again?

Let's look at the logic of what you said.....

It seems that the likelyhood of an electronic device effecting a plane is very small but not nil

The result of the plane being affected by an electronic device may be catastrophic

There is little or no benefit to the individual in keeping the electronic device switched on during the flight

So, as I see it, by keeping a phone switched on, the individual gains no benefit but induces a very small risk of a catastrophic event.......so why not just switch it off?

Just because you comply with a rule that you think to be worthless does not make you a weaker man

nickyboy

Anyone ever got asked to switch off the cameras ?

There are airlines consider cameras as "electronics". Japanese carriers do not say from the PA you have to switch off the cameras, but if there is a FA saw you taking pictures when the plane leave the gate til at the cruising altitude, they would come to you and ask you to switch it off.

Here's a fun experiment.

Take a GSM phone. If it has 3G, turn off 3G so that you're on EDGE only.
Place your phone near something that doesn't have specific shielding for it, e.g. computer speakers that are not branded "Works with iPhone."
Start making phone calls or accessing the data network.

Hear that bzzzt-bzzzt-bzzzzzzt?

I don't know what the specific interference concerns are or whether planes are designed to shield against GSM noise, but I do know that *this* in particular is very annoying when I'm sitting at my desk. I can't imagine how distracting it must be for a pilot if they happen to hear it.

Thus, I turn off my phone during takeoff and landing.

Preface: I turn off my cell phone as per the rules.

The pilot appears to have experienced a glitch in the plane's electronics or in signals. The pilot ascribed it to a cell phone, but that does not constitute evidence that a cell phone is what caused the problems; it represents an anecdotal claim.

I have an anecdote that does raise a question about whether some devices do interfere with the cockpit instruments. On a transatlantic flight last year (this was a repositioning ferry flight with no passengers or cargo so the potential for other possible sources of interference were a lot less) I was filming in the cockpit using my mobile phone in "flight" mode. During the mid-Atlantic section we were experiencing significant disturbance on HF when trying to contact either Piarco or Dakar Oceanic (we were crossing on a Southern track around 10N). A friendly JetBlue out of Santo Domingo was able to copy and kindly offered to play relay for us, but we simply could not communicate directly. After an hour or so, we were able to communicate with Cape Verde on VHF and I turned off my phone about the same time. Suddenly, the HF link with Dakar was functional again. Now, I know there could be plenty of explanations for this (solar activity, geographic anomalies, range, etc....) but the coincidence was too much to simply write off. I've flown hundreds of hours on that very airframe (indeed, our westbound crossing the previous night had no hassles whatsoever), but this was the only time I saw any comms problems.

I used to be a subscriber to the school of "much ado about nothing" but after that experience, I now have my doubts. People often don't realise how sensitive the equipment that guides ILS approaches can be to even tiny interference and in low-vis conditions, any responsible pilot has to err on the side of caution if he has any doubts about sources of interference.

I just wanted to come up with it.
It bothers me especially when some PAX GSM phone is searching for a network and I get the interference on my NC-headphones. :mad:

I can tell you it is indeed annoying and it makes the radio harder to hear.

I would think that they wanted to see if the problem went away if passengers turned their electronic devices off. It's normal, and expected, for the pilots to want to do everything they can think of to solve the problem.

P.S. I turn everything off. Even if I didn't think that my camera did not interfere with anything, as a passenger, I have the duty to comply with regulations and also it is polite to comply with requests. It is not for me to decide if it is dangerous or not. One thing for sure is that it does not create extra risk by turning them off.

What all the 'experts' here don't realize...


1) RF signal behavior in a long, metal tube is unpredictable
and can't be easily modeled. Any modeling or calculations
have to be statistical in nature, just as RF propogation is
statistical in nature.

2) The aircraft environment is a multipath environment and
is generally not 'Line of Sight' propogation, as in open range
testing. Even open range LOS testing is statistical.

3) Even a relatively small shift in position of a rediator or
the receiver of interference can change the signal strength
dramatically.

4) As stated in another post, "the cockpit" is not the only
place with susceptible equipment, antennas, or sensors.

5) Anything and everything is susceptible in some way.
Either we don't know what the mechanism is, or how it
will appear, or what will happen, but it will at some level
or some frequency. Fortunately, we can eliminate most,
but not all, of the problem equipment - both the raditors
and the susceptible equipment. But some of both types
(on both ends) will remain. All it takes is to wait for the
right combination. Even if a town has only two cars, the
chances of a crash are higher than you would think. It
could be the complacency. We seem to be complacent
in this thread.


6) It seems no-one has heard of 'constructive interference'.

7) You can't predict what signal levels will cause interference.

8) You don't know the state of the equipment in any aircraft,
never mind ALL aircraft. Are full EMI tests done on all aircraft
after any electric or electronic maintenance has been done?
No.

9) Any aircraft radio interference testing is incomplete. Not
necessarily by intent, but by the nature of radio interference
and all the possible combinations of test conditions. Testing
of one representative aircraft of a type can be extensive and
give some insight into the typical situation for RF immunity.
But even extensive testing is incomplete, and even minimal
EMI testing is impossible on all aircraft and at regular intervals.

10) Any testing of personal electronics is incomplete. These
are the interfering radiators. As mentioned in another post,
type testing of consumer equipment does not do a good job
of accounting for typical use, or for all usage situations. It
is common knowledge that accessory cords act as antennas
and not all accessories are used when testing this equipment,
and if done, it is impossible to test what might be the most
radiating arrangement. I personally know of a consumer RF
system (with an antenna) where the normally used cord acts
as much an antenna as the main, proper antenna. Consumer
and personal electronics testing would be uneconomical if the
testing was thorough. And after type acceptance, most of
the manufacturers make intentional or unintentional changes
(knowingly, or unknowingly), as in the 'benign' substitution of
a component by the contract manufacturer somewhere in
China. Usually, modified manufactured equipment is not re-
submitted for repeated type testing.

11) You can't predict what frequencies will cause interference.

12) You can't predict what frequencies will be emitted by any
personal electronics these days.

13) The number and variety of personal electronics made and
carried by passengers these days is growing rapidly.

14) There definitely HAS been testing.

15) The FAA has good reason to ban 'intentionally radiating'
equipment at ALL times.

16) Allowance has been made to operate equipment that does
not intentionally radiate because the levels of radiation are
usually much less. Usually...

17) The use of any equipment is only allowed above 10,000 ft.
Take-off and landing are critical phases where reaction times
to avoid a disaster are very small and there cannot be even
transient spurious interference with radios and navigation. It
seems OK by the authorities to allow cell phone while taxiing
after landing, but there is still a possibility of communication
and navigation problems, resulting in wandering into the path
of aircraft landing or taking off.

18) There are exceptions to the use of electronics, even if
they are not 'intentional radiators'. Examples are most radios
and receivers, which have a local oscillator (LO) that can be
a strong emitter.

19) Cell phones are 'intentional radiators'. Cell phone carriers
today shifting operation to new frequency bands and are using
more frequency bands. Does the 'testing' account for changing
conditions and rapid advances in technology. I really doubt it.

20) One person using a cell phone, GPS, or a laptop with Wi-Fi
still turned on will usually not be a problem. (Usually.) But if
everyone uses a combination of a variety of cell phones, Wi-Fi
and other radiating and unintentionally radiating devices, what
do you think the probablity of having a problem becomes? The
probablity explodes if everyone does it. And if, for example, an
airline installs Wi-Fi, then this will be at a certain frequency and
some advance testing can be done to reasonably assure there
will be no problems. And even the W-Fi will have to be turned
off for takeoff and landing.


The 'expert' opinions and attitutes here continue to amaze me.

There are many different types of aircraft being used in airline operations today, all with different layouts for communication and navigation systems. I'm surprised that people who haven't personally flown and operated these systems are so positive of what will and won't affect them.

Those with electrical engineering backgrounds have pointed out that a device would have to be fairly close to the communication equipment, which is absolutely true. On many aircraft the first row of F is too far away to have a noticeable effect on cockpit equipment, but the OP wasn't in a 777. If this was AE it was most likely an ERJ, and the distance between row 1 and the avionics equipment is not far at all - probably about 1.5 m. For those with more electrical engineering knowledge, what's the chances of a GSM phone interfering with equipment 1.5 m away? Having flown that aircraft before I can tell you that phones in the cabin can and do cause interference on the radio. When I flew it we would very rarely hear it inflight, so I'm guessing it was only the first row or two. If memory serves, the ERJ has about 25 antennae down the length of a 30 meter long aircraft, so you're probably never more than a meter away from an antenna (although I doubt many of them can pick up cell phone frequencies).

These days I rarely hear the interference come from a source other than the other pilot. Many of my coworkers have iPhones now, which seem to be especially noisy. Sometimes it's necessary to call mx control or dispatch when on the ground from the cockpit and those phones cause an infuriating level of interference. So, keeping in mind how much interference they cause and remembering how close the first few rows on an ERJ are to the cockpit I wouldn't be so quick to dismiss the OP's pilot's conclusion. Also note that Eagle all captains have been with the airline at least nine years. I'm guessing that pilot probably has more experience with the ERJ's systems and quirks than most of us here do.