Avionics and consumer electronics

Discussion in 'The Okie Corral' started by Roogalator, Sep 14, 2004.

  1. Roogalator

    Roogalator Senior Grackle

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    You know how on commercial flights they always tell you to turn off your cell phone, laptop, etc during the flight? Do those devices really interfere with the plane's avionics? Somehow it seems odd to me that a cheap little cell phone could interfere with a plane whose avionics alone probably cost several million dollars. Don't they have some sort of RF shielding around the plane's electronics?
     
  2. Texas T

    Texas T TX expatriate CLM

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    Sometimes it is merely a particular airline's preference as to what can be used and what can't. There is a thread going on at TreoCentral right now about the use of the Treo 600 on board flights. Some airlines (SW specifically) are more stringent about its use than others. I actually have a letter in to SWA right now asking for clarification on this specific issue.

    I think when it comes right down to it, it is more of a flight atttendant by flight attendant issue as I've flown SWA with my Treo and not had any problems (it has an aircraft mode) while others have been told that they can't even use the PDA functions of the unit while in the air.

    T
     

  3. ChinaCave

    ChinaCave

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    Check out the current issue of Air & Space Magazine. They have an excellent article on just that. Precisly BECAUSE so many consumer gagets are very, uh, cost-effective, they cannot be made so that they don't spew out stuff at frequencies that they do not intend. These extra or spurious emmisions are the reason they tell you to shut it off. They are what will interfeer with the navcom stuff in the airlines.

    After making a call in flight in my club Archer, and listening to the mess in my headphones, I see the effects of cheap consumer stuff.
     
  4. Roogalator

    Roogalator Senior Grackle

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    But wouldn't you think that for something as critical as navcom they'd figure out a way to shield it from RF noise? Military planes must have some way of doing this -- otherwise some dipthong with a Radio Shack xmitter could flummox all 13 gazillion dollars worth of electronics in some incoming warbird. Also, how do they shield the plane's navcom from their own onboard phones?
     
  5. ateamer

    ateamer NRA4EVR

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    First off, money. Second, Flitefones are integrated into the aircraft's systems. They are designed to be used in flight without interference. Regular cell phones are designed to be as cheap as possible without regard to interfering with navigation equipment. That is why Flitefones cost so much.
    ----------------------------------------------------------------
    AirCell AT.02 (Transceiver)
    Reg........ $ 8,495 ... Special!........ $ 7,689
    AirCell Standard Low Profile Antenna (CI-5000)
    Reg........ $ 1,149 ... Special!........ $ 1,089
    AirCell Standard Remote Handset (500-10036-001)
    Reg........... $ 595 ... Special!........... $ 549
    Standard Installation only $1,489 plus parts in most Single Engine and Light Twin Aircraft. $2,989 plus parts in most cabin class aircraft.
     
  6. sf340flyer

    sf340flyer

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    The feds are pretty specific about their wording when it comes to the use of portable electronic devices. However there have been several times when we could hear interfearance (usually a clicking sound) over the aircraft radios. Amazingly this interfearance would stop shortly after we would have the flight attendant walk through the cabin and have a passenger turn off a cell phone that had been left on. Sometimes people are using the phones for games etc not knowing that they are transmitting etc even when they are not making a call.
     
  7. Mass10mm

    Mass10mm Armed Yankee

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    The issue of cell phone use in flight is very clear: it is illegal. It has nothing to do with avionics - it's related to the cell phone system, and is an FCC rule. From a high altitude, a cell phone can tie up a particular frequency for a hundred miles in all directions, while on the ground, the same cell phone's transmissions will go a few miles at most. That's the whole concept of cell phones - the use of the same frequencies by hundreds of conversations nationwide simultaneously. Since each phone's signals can go only a short distance, the frequencies can be re-used a short distance away. The FCC has forbidden using a cell phone from any aircraft not touching the ground, and has asked the FAA to help enforce this rule.

    The one exception, as always, is emergencies. Whenever I'm piloting, I always carry a switched-off phone in my flight bag, just in case of total radio failure or off-field landing.
     
  8. CaptainOveur

    CaptainOveur

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    Another point is the random-chance possibility;

    There are all sorts of electronics running through the fuselage, to the engines, to sensors in various parts of the aircraft, etc. Now, planes have to be made as light as practical to be as cost-efficiant as possible, so sheilding every wire from every feasble source of interfearence is not really possible.

    The random chance though comes from running electronics that leak radiation and this could possibly interfear with the airplane by cutting across a wire and inducing a current, which is how you get erroneous readings/problems. It is impossible to concieve of every possible angle and frequency interaction in the plane, so to be on the safe side, certain devices are prohibited from being used.

    It's a fine line we are walking on, we don't want to find out that our concerns were warrented when we allow the unrestricted use of these devices and a plane crashes.
     
  9. Jay D.

    Jay D.

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    I think that it is all a conspiracy. The airlines want you to use thier built in phones so that they will make money. I have flown cross country many times in my squadrons helicopters and have used the phone for games and text messaging, etc. Cant really use it for a call because the aircraft is so damn loud. Our pilots could care less.
     
  10. CaptainOveur

    CaptainOveur

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    And if that's true, so what?

    Would you rather pay $50 more in ticket prices?