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posted by Fnord666 on Friday July 26 2019, @06:07AM   Printer-friendly
from the have-you-tried-turning-it-off-and-back-on-again? dept.

Submitted via IRC for Bytram

Airbus A350 software bug forces airlines to turn planes off and on every 149 hours

Some models of Airbus A350 airliners still need to be hard rebooted after exactly 149 hours, despite warnings from the EU Aviation Safety Agency (EASA) first issued two years ago.

In a mandatory airworthiness directive (AD) reissued earlier this week, EASA urged operators to turn their A350s off and on again to prevent "partial or total loss of some avionics systems or functions".

The revised AD, effective from tomorrow (26 July), exempts only those new A350-941s which have had modified software pre-loaded on the production line. For all other A350-941s, operators need to completely power the airliner down before it reaches 149 hours of continuous power-on time.

Concerningly, the original 2017 AD was brought about by "in-service events where a loss of communication occurred between some avionics systems and avionics network" (sic). The impact of the failures ranged from "redundancy loss" to "complete loss on a specific function hosted on common remote data concentrator and core processing input/output modules".

In layman's English, this means that prior to 2017, at least some A350s flying passengers were suffering unexplained failures of potentially flight-critical digital systems.

Not a power of two. I wonder why 149 hours?


Original Submission

 
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  • (Score: 1) by fustakrakich on Friday July 26 2019, @06:15AM (4 children)

    by fustakrakich (6150) on Friday July 26 2019, @06:15AM (#871350) Journal

    It's a prime number

    --
    La politica e i criminali sono la stessa cosa..
  • (Score: 5, Insightful) by kazzie on Friday July 26 2019, @06:41AM (3 children)

    by kazzie (5309) Subscriber Badge on Friday July 26 2019, @06:41AM (#871356)

    Alternatively, 2^29 milliseconds is 149 hours and eight minutes, give or take a few seconds.

    29 bits may seem a strange number, but it's nothing unusual in the world of embedded devices. Several Intel (ex-Altera) FPGAs use a 29-bit watchdog counter, for example.

    • (Score: 0) by Anonymous Coward on Friday July 26 2019, @02:59PM (1 child)

      by Anonymous Coward on Friday July 26 2019, @02:59PM (#871493)

      So, lemme get this straight. About once a week, the watchdog takes a little siesta? Well, that's good to know before breaking and entering. Now, can you tell us when the dog is asleep?

      • (Score: 2) by driverless on Saturday July 27 2019, @08:42AM

        by driverless (4770) on Saturday July 27 2019, @08:42AM (#871817)

        It doesn't take a siesta, it nips around the back to, uhh, take care of business, if you get my drift.

    • (Score: 2) by danmars on Monday July 29 2019, @09:21PM

      by danmars (3662) on Monday July 29 2019, @09:21PM (#872818)

      I came to say the same thing. A little over 2^29.

      2^29 = 536870912
      149 h = 536400000 ms