4 ms·

Thanks for sharing! I would have always assumed that there was an air gap between the consumer focused IFE networking gear and the flight systems.

StavrosK 12y ago
Why are the two systems even communicating?
- WatchDog 12y ago
  That's a good question, one example I can think of is the TV channel on some aircraft that displays positional and airspeed information to passengers. I assume this data comes somewhere from the flight computers.
  - gizmo686 12y ago
    Probably, although if you were paranoid enough (or required by regulation), you could airgap the TVs and give them information through a normal GPS system (minus the artificial altitude restriction), or have a hardware unidirectional data path. More reasonably, you could consider the TVs part of the flight system network (with many of the same protections to prevent someone from physically opening one and hacking), and still have an airgapped wifi network.
    - StavrosK 12y ago
      What altitude restriction? My phones' GPS works fine in flight, I use it a lot to check speed and altitude.
      - klodolph 12y ago
        Yeah, the altitude restrictions don't really apply to commercial flight. You can conduct a test yourself, you just need to get a little higher and travel a little faster than your typical 757. Try attaching your cell phone to a rocket travelling over 1200 mph or above 60,000 feet, you'll find that your GPS unit basically shuts down. That's not to say that your GPS hardware is incapable of operating under those parameters, it's just designed to shut down so it can't be used to guide ICBMs. Commercial airplanes typically operate at half the altitude and speed which would trigger the condition.
        MichaelApproved 12y ago
        Don't both speed and altitude trigger the block? The gps must be over a certain altitude AND be going faster than a certain speed.
        callesgg 12y ago
        It is one or the other.
        proexploit 12y ago
        IIRC, the legal requirement is to shut down with both conditions are present, some GPS manufacturers simply found it easier to implement each restriction separately.
        michaelt 12y ago
        According to [1] some manufacturers apply this limit when both speed and altitude limits are reached, while other manufacturers disable tracking when only a single limit is reached. The limits are 1,200 mph speed and 18,000 m altitude. Google tells me a 747's limits are around 615 mph and 14,000 m; Concorde's limits were closer to 1,350 mph and 18,300 m. Still, I'm sure if you're making an airliner you can get access to GPS receivers that will work even at maximum speed and altitude! [1] http://en.wikipedia.org/w/index.php?title=CoCom&oldid=608893426#Legacy http://en.wikipedia.org/w/index.php?title=CoCom&oldid=608893...
        kalleboo 12y ago
        Do the limitations also apply to GLONASS which is now in all modern devices?
  - sjwright 12y ago
    For stuff like positional and airspeed information, it would not be difficult to design a connection that is physically limited to one-way communication. It would also seem sensible that any interaction the pilots might want to perform on the cabin computer systems could be done by giving them a terminal on that network.
    - com2kid 12y ago
      For some stuff that did have data sharing there was a very tightly controlled pipe. Oddly enough it was Linux on one side and Windows on the other. The level of scrutiny that IPC (inter-processor communication) channel got was insane. It is probably one of the safest IPC channels in existence! Unfortunately I didn't fully grasp what systems it was connecting, aviation is full of its own parallel set of jagon that I didn't fully learn in my short time at Boeing!
      - sjwright 12y ago
        > Oddly enough it was Linux on one side and Windows on the other. Doesn't sound at all odd -- quite sensible actually. Though I would probably have suggested a pairing more along the lines of OpenBSD/x64 and Linux/ARM or some-such. It depends on what the remainder of the systems is using. This is a perfect example of where ecosystem diversity is a Good Thing.
  - empressplay 12y ago
    Every map channel I've seen has been analog, even on otherwise purely digital IFE, implying that the map video signal is generated by a device networked on the avionics side and then piped by standard RF to the IFE, like the address system. So no two-way communication.
    - kalleboo 12y ago
      Newer ones are digital (I've seen 3D interactive ones on an A380)
com2kid 12y ago
Most IFE stuff is aftermarket. Boeing was aiming to make things like Wi-Fi standard across all 787s. I'm not sure to what extent IFE was part of 787 plans. I mostly worked on the Electronic Flight Bag, which is a hilarious case of Boeing realizing that paper flight bags were asinine, and then coming up with an industrial strength solution to the problem of carrying what amounted to a few PDFs on board an airplane. Last time I checked (years ago) airlines were just moving to iPads whenever possible. (A flight bag has hundreds upon hundreds of pages of paper that are required by law to be on board an airplane with the pilot, everything from safety literature to information on the current flight, it is a huge hassle) Again the problem here is, if Boeing ships something stock, the FAA equivalent in every market a plane will be sold into has to agree to every decision made. If a single regulatory body anywhere declares that iPads are not safe for use onboard an airplane, well, the entire idea gets scrapped. This happens to a lot of good ideas. If Boeing had its way, we'd all have in flight cellular, Wi-Fi, and more, as options on every plane trip we took. Boeing spends a lot of time and a lot of effort on what they know will likely be futile efforts to improve the passengers' experience. But they try anyway. Everyone I met working there flat out loved airplanes with the same zest and zeal we all here share about technology.
- joezydeco 12y ago
  The latest flightbag systems look a bit more sophisticated than a fancy PDF reader on a tablet. Here's a glimpse of the flightbag that Lufthansa is using on the B747. It actively maps plane position in the terminal among other things. https://www.youtube.com/watch?v=nhXXjNybx6A&t=2m4s https://www.youtube.com/watch?v=nhXXjNybx6A&t=2m4s https://www.youtube.com/watch?v=nhXXjNybx6A&t=13m43s https://www.youtube.com/watch?v=nhXXjNybx6A&t=13m43s (FYI, PilotsEye.TV on YouTube is incredible if you enjoy geeking out on airplane stuff. They somehow convinced a few European carriers to mount cameras all over the cockpits and talk to the pilots in-flight. There are DVDs as well but I think they're all in German. Check out the A340 that loses an engine in the air. I don't think that's ever been publicly filmed before).
  - com2kid 12y ago
    True! But the paper books ended up being replaced by ipads in some cases. The EFB does other stuff as well, but the effort around getting all the papers onto it versus "use an iPad" is rather amusing imho.

StavrosK 12y ago

Why are the two systems even communicating?

WatchDog 12y ago
That's a good question, one example I can think of is the TV channel on some aircraft that displays positional and airspeed information to passengers. I assume this data comes somewhere from the flight computers.
- gizmo686 12y ago
  Probably, although if you were paranoid enough (or required by regulation), you could airgap the TVs and give them information through a normal GPS system (minus the artificial altitude restriction), or have a hardware unidirectional data path. More reasonably, you could consider the TVs part of the flight system network (with many of the same protections to prevent someone from physically opening one and hacking), and still have an airgapped wifi network.
  - StavrosK 12y ago
    What altitude restriction? My phones' GPS works fine in flight, I use it a lot to check speed and altitude.
    - klodolph 12y ago
      Yeah, the altitude restrictions don't really apply to commercial flight. You can conduct a test yourself, you just need to get a little higher and travel a little faster than your typical 757. Try attaching your cell phone to a rocket travelling over 1200 mph or above 60,000 feet, you'll find that your GPS unit basically shuts down. That's not to say that your GPS hardware is incapable of operating under those parameters, it's just designed to shut down so it can't be used to guide ICBMs. Commercial airplanes typically operate at half the altitude and speed which would trigger the condition.
      - MichaelApproved 12y ago
        Don't both speed and altitude trigger the block? The gps must be over a certain altitude AND be going faster than a certain speed.
        callesgg 12y ago
        It is one or the other.
        proexploit 12y ago
        IIRC, the legal requirement is to shut down with both conditions are present, some GPS manufacturers simply found it easier to implement each restriction separately.
        michaelt 12y ago
        According to [1] some manufacturers apply this limit when both speed and altitude limits are reached, while other manufacturers disable tracking when only a single limit is reached. The limits are 1,200 mph speed and 18,000 m altitude. Google tells me a 747's limits are around 615 mph and 14,000 m; Concorde's limits were closer to 1,350 mph and 18,300 m. Still, I'm sure if you're making an airliner you can get access to GPS receivers that will work even at maximum speed and altitude! [1] http://en.wikipedia.org/w/index.php?title=CoCom&oldid=608893426#Legacy http://en.wikipedia.org/w/index.php?title=CoCom&oldid=608893...
      - kalleboo 12y ago
        Do the limitations also apply to GLONASS which is now in all modern devices?
- sjwright 12y ago
  For stuff like positional and airspeed information, it would not be difficult to design a connection that is physically limited to one-way communication. It would also seem sensible that any interaction the pilots might want to perform on the cabin computer systems could be done by giving them a terminal on that network.
  - com2kid 12y ago
    For some stuff that did have data sharing there was a very tightly controlled pipe. Oddly enough it was Linux on one side and Windows on the other. The level of scrutiny that IPC (inter-processor communication) channel got was insane. It is probably one of the safest IPC channels in existence! Unfortunately I didn't fully grasp what systems it was connecting, aviation is full of its own parallel set of jagon that I didn't fully learn in my short time at Boeing!
    - sjwright 12y ago
      > Oddly enough it was Linux on one side and Windows on the other. Doesn't sound at all odd -- quite sensible actually. Though I would probably have suggested a pairing more along the lines of OpenBSD/x64 and Linux/ARM or some-such. It depends on what the remainder of the systems is using. This is a perfect example of where ecosystem diversity is a Good Thing.
- empressplay 12y ago
  Every map channel I've seen has been analog, even on otherwise purely digital IFE, implying that the map video signal is generated by a device networked on the avionics side and then piped by standard RF to the IFE, like the address system. So no two-way communication.
  - kalleboo 12y ago
    Newer ones are digital (I've seen 3D interactive ones on an A380)

com2kid 12y ago

Most IFE stuff is aftermarket. Boeing was aiming to make things like Wi-Fi standard across all 787s. I'm not sure to what extent IFE was part of 787 plans. I mostly worked on the Electronic Flight Bag, which is a hilarious case of Boeing realizing that paper flight bags were asinine, and then coming up with an industrial strength solution to the problem of carrying what amounted to a few PDFs on board an airplane. Last time I checked (years ago) airlines were just moving to iPads whenever possible. (A flight bag has hundreds upon hundreds of pages of paper that are required by law to be on board an airplane with the pilot, everything from safety literature to information on the current flight, it is a huge hassle) Again the problem here is, if Boeing ships something stock, the FAA equivalent in every market a plane will be sold into has to agree to every decision made. If a single regulatory body anywhere declares that iPads are not safe for use onboard an airplane, well, the entire idea gets scrapped. This happens to a lot of good ideas. If Boeing had its way, we'd all have in flight cellular, Wi-Fi, and more, as options on every plane trip we took. Boeing spends a lot of time and a lot of effort on what they know will likely be futile efforts to improve the passengers' experience. But they try anyway. Everyone I met working there flat out loved airplanes with the same zest and zeal we all here share about technology.

joezydeco 12y ago
The latest flightbag systems look a bit more sophisticated than a fancy PDF reader on a tablet. Here's a glimpse of the flightbag that Lufthansa is using on the B747. It actively maps plane position in the terminal among other things. https://www.youtube.com/watch?v=nhXXjNybx6A&t=2m4s https://www.youtube.com/watch?v=nhXXjNybx6A&t=2m4s https://www.youtube.com/watch?v=nhXXjNybx6A&t=13m43s https://www.youtube.com/watch?v=nhXXjNybx6A&t=13m43s (FYI, PilotsEye.TV on YouTube is incredible if you enjoy geeking out on airplane stuff. They somehow convinced a few European carriers to mount cameras all over the cockpits and talk to the pilots in-flight. There are DVDs as well but I think they're all in German. Check out the A340 that loses an engine in the air. I don't think that's ever been publicly filmed before).
- com2kid 12y ago
  True! But the paper books ended up being replaced by ipads in some cases. The EFB does other stuff as well, but the effort around getting all the papers onto it versus "use an iPad" is rather amusing imho.