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Boeing 787 "Blacklisted" From Some Air Traffic Control Services (flightglobal.com)

Posted by timothy on from the flight-oh-oh-nine-please-repeat-your-position dept.

An anonymous reader writes: A software glitch causes the Boeing 787 to report its position incorrectly, which has led Australia and Canada to 'blacklist' the aircraft from using ADB-S and until it is resolved the latest Boeing is treated as an aircraft without ADS-B capabilities. The practical implication is that the aircraft is not allowed to use reduced separation procedures and an maximum altitude limit of 29,000 feet was also considered. Boeing denies that the bug causes a safety hazard because existing services (radar) still allow safe operation. A bugfix is coming to restore ADS-B functionality.

15 of 96 comments (clear)

  1. It's not really a blacklist then, is it? by halivar · · Score: 2, Insightful

    It's graceful degradation.

    1. Re:It's not really a blacklist then, is it? by Anonymous Coward · · Score: 5, Informative

      It's graceful degradation.

      No, a graceful degradation would be the plane recognizing it's not operating correctly and falling back to the older service. This is a case where the plan is actually trying to use the newer/better service, failing to do so correctly, and it not aware that it is failing to do so. The humans involved are noticing the error and have had the blacklist the plan from the newer system and manually force a fallback to the old system.

      I mean seriously, the second sentence in TFA even says:
      Boeing says a service bulletin with instructions for operators to correct the position reporting error will be released “imminently"

  2. at least is not tcas off by Joe_Dragon · · Score: 2

    as that can end deadly.

    1. Re:at least is not tcas off by digitig · · Score: 3, Interesting

      I'd be interested to know where the glitch is. If it's just in the ADS-B system then with the restrictions in the article it just costs time and money. But if it's in the navigation system then the aircrew and TCAS will have wrong information about where the aircraft is, which is far more worrying.

      --
      Quidnam Latine loqui modo coepi?
    2. Re:at least is not tcas off by Anonymous Coward · · Score: 2, Interesting

      From what I gather the pilot/co-pilot are receiving the correct information, the article notes one of the first instances where the issue was noticed "The controllers alerted the crew by radio, but the pilots insisted their instruments showed they were still on course." It sounds like there is a system to pass information from the aircraft system to a separate ATC-B beacon, for some reason that system under some circumstances only passes the lat or long, not both. The ATC-B beacon then has another (what I would call) fault where if it receives partial information it fills in the blank with whatever it last received without noting the degraded information. I can understand the beacon wanting to keep transmitting some information, but much as a phone based GPS it should note that in some way. And this doesn't just happen for a few seconds or throw off the location a few hundred feet, one of the situations resulted in the aircraft showing its location 38 nautical miles from where it actually was.

    3. Re:at least is not tcas off by DesertNomad · · Score: 4, Informative

      I run a number of ADS-B receivers and feed the data into FlightAware. I have seen a number of a/c locally that are in very wrong positions (well over the 70 km mentioned in TFA) and suddenly jump into the "right" positions. Sounds like interface problems.

      The ADS-B system is fairly simple, and as long as the right lat-lon string is inputted, it should transmit the right position. Maybe it's a "units" issue similar to the "units" issue that caused the Mars spacecrafts more than a decade ago to make an unexpected and unfortunate (very) hard landing...

    4. Re:at least is not tcas off by parkinglot777 · · Score: 3, Informative

      Here is the cause on the TFA (which is what Boeing said)...

      In rare cases, after passing a planned turn upon crossing a waypoint, the data packets that arrived at the transponder would contain either the aircraft’s latitude or longitude, but not both. In those cases, the ADS-B transponder’s software would extrapolate the 787’s position based on the previous flight track before it made a planned turn at a waypoint. It would continue reporting the aircraft erroneously on the incorrect track until it received a data packet containing both the latitude and the longitude of the aircraft.

    5. Re:at least is not tcas off by nadaou · · Score: 2

      The problem is incomplete messages being broadcast. Sometimes the lat is missing, sometimes the long is missing. In these cases the system was using dead reckoning to extrapolate the missing value based on the previous ones. Not ideal but roughly giving you the right answer when traveling in a straight line. Gives the wrong answer after turning at a waypoint. When a complete message finally does make it through the plane jumps back to it's correct position.

      --
      ~.~
      I'm a peripheral visionary.
  3. So the plane tells ATC where it is... by Viol8 · · Score: 2

    ... instead of ATC relying on radar. What could possibly go wrong?

    1. Re:So the plane tells ATC where it is... by brambus · · Score: 4, Informative
      I know you were trying to be snarky, but you did accidentally ask a good question where the answer isn't trivial:
      • Since the dawn of radar ATC, civilian radar has been SSR - Secondary Surveillance Radar, meaning, it requires cooperation from the aircraft. SSR gives you the horizontal location of the target, but not its elevation. Instead, together with the actual radar return, the aircraft responds using a short digital code that identifies it and tells you its altitude (as read from the onboard altimeter by the SSR equipment on the aircraft). SSR has numerous advantages over PSR, mainly its not as complex, doesn't require as much power and has greater range, all of which are useful in a civilian environment. Also, it has no military application, so it carries far fewer export concerns.
      • Even so, SSR is still very expensive and providing good coverage is difficult to impossible. Even modern industrialized countries such as the USA have many places where radar coverage is simply unavailable (especially at lower altitudes). In less well of places, such as large areas of Africa, radar coverage is nonexistent.
      • The vast majority of all aircraft (and nearly all commercial aircraft) have some sort of navigational equipment that is completely independent of radar coverage and is reasonably accurate to provide traffic separation services. Put simply, aircraft are able to navigate without any ground assistance.

      And so the natural evolution is to largely abandon SSR (except for areas of extremely high traffic density) and instead place around the country only small receiver stations that listen to aircraft position reports. Using those then, ATC can build a complete traffic picture and provide separation services without having to maintain expensive ground equipment.

    2. Re:So the plane tells ATC where it is... by Viol8 · · Score: 2

      "Using those then, ATC can build a complete traffic picture and provide separation services without having to maintain expensive ground equipment."

      Until some pilot decides to switch the transponder off and the plane effectively becomes invisible. But that would never happen. Oh , wait...

    3. Re:So the plane tells ATC where it is... by BostonPilot · · Score: 2

      ADS-B Out, which is the system I'm talking about, cannot be switched off. It becomes active as soon as the avionics stack is powered up.

      What happens if I:

      1) Hit the "off" button on my Garmin GTX-330 ES (1080 extended squitter)?
      2) Pull the breaker?
      3) Turn off the GPS that is feeding it data?
      4) Similar stuff if I have a 978 UAT ADS-B out?

      Sure *seems* like I can turn it off if I want to. I'd be breaking a rule for sure, but not sure what you think prevents me from turning it off?

  4. Not a safety hazard? My ass! by LordKronos · · Score: 4, Insightful

    Nav Canada first detected a problem on 1 July 2014 when controllers noticed a 787 appearing to deviate up to 38nm (70km) from its planned track. The controllers alerted the crew by radio, but the pilots insisted their instruments showed they were still on course. Suddenly, however, the 787 “was observed jumping back to the flight plan route” on the controller’s screens, according to ICAO documents.

    I'm sorry, but if a plane is reporting that it is 70km from where it actually is, that's no small deviation. That deviation is more than 10 times the required flight separation. It may not pose a safety hazard once controllers already know they have to fall back to the older system. But before this was discovered? That's a HUGE safety hazard. The only reason they can get away with claiming it wasn't a safety hazard was because they lucked out and the system only screwed up when there were no other planes around

  5. The underlying problem ... by PPH · · Score: 4, Interesting

    ... is that the problem was traced back to the 787 avionics network. Information sent from the GPS (where the data originates) to the transponders (where it is sent out to air traffic control). This is the same network which attracted attention when Boeing asked for a special condition exempting the 787 from a requirement to isolate critical functions from things like the passenger entertainment system. Now, nobody has tracked down exactly what caused this communications glitch. And they may never do so. But their innovations may be coming back to bite them in the ass.

    --
    Have gnu, will travel.
  6. bugfix? by HideyoshiJP · · Score: 3, Funny

    "A bugfix is coming to restore ADS-B functionality."

    $adsb.model = "777-200ER";