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Wi-Fi Shown To Interfere With Aircraft Systems

Posted by Soulskill on from the nobody-tell-the-tsa dept.

lukehopewell1 writes "It's official: using Wi-Fi on a plane can interfere with a pilot's navigational equipment, according to airline equipment manufacturers Honeywell Avionics and Boeing today. Boeing confirmed to ZDNet Australia that the issue does exist, but said it has not delivered any planes suffering the fault. 'Blanking of the Phase 3 Display Units has been reported during airline EMI (electromagnetic interference) certification testing of wireless broadband systems on various Next-Generation 737 aeroplanes,' Boeing said."

8 of 300 comments (clear)

  1. FAIL by diskofish · · Score: 3, Informative

    The navigational equipment should be designed so it is tolerant of this sort of interference.

    1. Re:FAIL by the_raptor · · Score: 5, Informative

      Go learn about RF. At the frequencies used by Wi-Fi a resonant antenna is only a few CMs long, ie about the length of common circuit traces on the PCB's. Even if you completely shield the control units RF can still leak inside through cabling. There is no magic way to design electronics that are RF immune*, it requires real world testing to discover such faults, as happened here.

      The only way to make extremely RF tolerant electronics is to use analog vacuum tube based designs (the Russians continued using tube designs into the 90's).

      * Making bug free software is significantly easier.

      --

      ========
      CINC, 4th Penguin Legion
    2. Re:FAIL by imgod2u · · Score: 5, Informative

      Most electronic designers are competent enough to put a choke at their power line and a bandpass filter at their cabling. It's not "easy" but it's done in just about any military grade electronics. I guess Boeing engineers didn't think it was necessary.

    3. Re:FAIL by crakbone · · Score: 4, Informative

      Some of these planes and designs are well over 30 years old. I doubt they thought back then that people would each have three or four mobile transmitters let alone the idea of putting in a big transmitter inside the cabin to coordinate a bunch of little ones.

    4. Re:FAIL by digitig · · Score: 3, Informative

      I guess you're not an EE either, then, because no communication system uses pure, unmodulated frequencies. And anyway, if that extremely high-powered signal is lower in frequency than the other one there's every chance it will contain harmonics that are not necessarily orthogonal to the other signal.

      --
      Quidnam Latine loqui modo coepi?
    5. Re:FAIL by mangu · · Score: 5, Informative

      Most electronic designers are competent enough to put a choke at their power line and a bandpass filter at their cabling. It's not "easy" but it's done in just about any military grade electronics

      And to play a violin all you need to do is to draw the bow across the strings. There's a lot more to this than theory.

      A choke is inductive at a limited range of frequencies, at other frequencies it acts as a capacitor. Likewise, put a high enough frequency across a capacitor and its behavior becomes inductive. Electromagnetic compatibility (EMC) is a very complex subject, there are no easy solutions and it's nearly impossible to have a perfect solution that works at all frequencies.

      The 2.4 GHz band used in WiFi is one of the most difficult to shield. All the small metallic parts used in electronic equipment, like screws and button levers, are in the same size magnitude as the wave, so there are plenty of conductive parts to retransmit and conduct the radio frequency.

      I guess Boeing engineers didn't think it was necessary.

      You guessed wrong.

  2. This is a non-story by gad_zuki! · · Score: 5, Informative

    Not only is it for one specific module, its only at elevated power levels, not typical power levels. Lets watch the corporate media fuck this up and turn into a scare tactic to show more ads to morons.

    Boeing, meanwhile, says: "Current testing by Boeing and Honeywell has determined that blanking may occur when a DU is subjected to testing procedures specified by the FAA requirements (AC-20-164) during installations of Wi-Fi systems on the airplane. Based on testing that has been conducted, Boeing and Honeywell have concluded that actual EMI levels experienced during normal operation of typical passenger Wi-Fi systems would not cause any blanking of the Phase 3 DU. This issue does not exist with the Phase 1 or 2 DU's."
    Honeywell says that, during recent ground testing "at elevated power levels", the company observed a momentary blanking on the 'flat panel' liquid crystal displays that it developed and pioneered for Boeing.
    "The screens reappeared well within Boeing's specified recovery time frame. The screens have not blanked in flight and are not a safety of flight issue. Honeywell is working to ensure the problem is addressed and fixed and that our technology will continue to exceed specifications," says Honeywell.

    http://www.flightglobal.com/articles/2011/03/10/354179/wi-fi-interference-with-honeywell-avionics-prompts-boeing.html

  3. What sort of equipment is this? by vawwyakr · · Score: 5, Informative

    So the company just admitted that their (likely expensive) aviation equipment (displays?) are more error prone from EMI than say....my desktop pc...phone...digital watch? What sort of equipment are these people working with? Consumer electronics are bombarded by this sort of EMI constantly and I don't see any displays blanking in my office. In an airplane I would have assumed they would have to have MORE shielding because at altitude they have less shield from solar radiation which is well known for being harmful to electronics where my wifi adapter hasn't fried a single piece of electronics...yet. This still sounds like total BS to me.