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posted by martyb on Monday July 19, @02:19PM   Printer-friendly [Skip to comment(s)]
from the Gasping-for-air dept.

FAA orders checks on 9,300 Boeing 737 planes for possible switch failures:

WASHINGTON, July 15 (Reuters) - The Federal Aviation Administration (FAA) on Thursday issued a directive to operators of all Boeing Co (BA.N) 737 series airplanes to conduct inspections to address possible failures of cabin altitude pressure switches.

The directive requires operators to conduct repetitive tests of the switches and replace them if needed. The directive covers 2,502 U.S.-registered airplanes and 9,315 airplanes worldwide.

It was prompted after an operator reported in September that both pressure switches failed the on-wing functional test on three different 737 models.

The FAA said failure of the switches could result in the cabin altitude warning system not activating if the cabin altitude exceeds 10,000 feet (3,050 m), at which point oxygen levels could become dangerously low.

Airplane cabins are pressurized to the equivalent of not more than 8,000 feet (2438 m).

[...] Due to the importance of functions provided by the switch, the FAA in 2012 mandated all Boeing 737 airplanes utilize two switches to provide redundancy in case of one switch's failure.

The directive covers all versions of the 737 jetliners, including the MAX, but is unrelated to any issues related to the MAX's return to service last November.


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  • (Score: 4, Interesting) by Beryllium Sphere (r) on Monday July 19, @02:26PM (6 children)

    by Beryllium Sphere (r) (5062) on Monday July 19, @02:26PM (#1157879)

    Even for something that was not life safety critical, they did redundancy without being told to, and to prevent common mode failures used different designs for the primary and backup.

    • (Score: 5, Insightful) by Spamalope on Monday July 19, @03:28PM (4 children)

      by Spamalope (5233) on Monday July 19, @03:28PM (#1157890) Homepage

      Whereas now Boeing designs the plane, then removes the safety features they think they can get away with and sells them back at high markups (according to pilots vlogging about the changes over there). For the MAX... why is there only one angle of attack sensor when their new programming to 'fake' a 737 NG so no retraining is needed made that sensor so critical it'll result in a loss of the aircraft if the single sensor fails.

      I'm curious: Will EA sue them for copying their business methods?

      • (Score: 2) by c0lo on Monday July 19, @04:03PM (3 children)

        by c0lo (156) Subscriber Badge on Monday July 19, @04:03PM (#1157901) Journal

        Will EA sue them for copying their business methods?

        Huh? What does EA have to do with the angle of attack sensors?

        --
        https://www.youtube.com/watch?v=aoFiw2jMy-0
        • (Score: 1, Touché) by Anonymous Coward on Monday July 19, @04:48PM (1 child)

          by Anonymous Coward on Monday July 19, @04:48PM (#1157930)

          What does EA have to do with the angle of attack sensors?

                    Upselling
          relevant sentence:
                    removes the safety features they think they can get away with and sells them back at high markups

          you know; like EA pulls all the good parts of their games out and makes you buy it via DLC

          • (Score: 0) by Anonymous Coward on Tuesday July 20, @10:59PM

            by Anonymous Coward on Tuesday July 20, @10:59PM (#1158490)

            Coming soon: airplane loot boxes. Want to upgrade your seats? Add safety features? Different paint job? Just buy one of our brand new Boeing Loot Boxes to get a chance to win a free random* upgrade.

        • (Score: 0) by Anonymous Coward on Monday July 19, @05:15PM

          by Anonymous Coward on Monday July 19, @05:15PM (#1157945)
          It's the old TV development model. Build the best one possible, and then start removing/cheapening out on parts until it stops working.
    • (Score: 5, Insightful) by RS3 on Monday July 19, @05:09PM

      by RS3 (6367) on Monday July 19, @05:09PM (#1157941)

      Even for something that was not life safety critical, they did redundancy without being told to, and to prevent common mode failures used different designs for the primary and backup.

      And then the MBAs took over...

      (reference to short-term profit becoming the priority in almost every sector of society)

  • (Score: 0) by Anonymous Coward on Monday July 19, @02:41PM

    by Anonymous Coward on Monday July 19, @02:41PM (#1157883)

    i think what we have learned so far is that anything will and can break. even islands where bikinis grow on trees...

  • (Score: 0) by Anonymous Coward on Monday July 19, @03:00PM

    by Anonymous Coward on Monday July 19, @03:00PM (#1157885)

    Secure your own oxygen mask before assisting others.

  • (Score: 0) by Anonymous Coward on Monday July 19, @05:17PM (1 child)

    by Anonymous Coward on Monday July 19, @05:17PM (#1157948)

    Is it a Boeing? I won't fly in it.

    • (Score: 2) by bart on Friday July 23, @03:40PM

      by bart (2844) on Friday July 23, @03:40PM (#1159415)

      No it's like this: "If it's Boeing I ain't going". That way it's easier to remember. :-)

  • (Score: 0) by Anonymous Coward on Monday July 19, @07:24PM (6 children)

    by Anonymous Coward on Monday July 19, @07:24PM (#1157985)

    Airplane cabins are pressurized to the equivalent of not more than 8,000 feet (2438 m).

    Cross-country and international flights cruise at 30-50k feet. What's the cabin pressurization at these altitude?

    • (Score: 2) by DannyB on Monday July 19, @07:58PM (2 children)

      by DannyB (5839) Subscriber Badge on Monday July 19, @07:58PM (#1158002) Journal

      Answer: from the part you quoted, I would say pressurization is to somewhere = 8,000 feet. (2438.4 meters)

      --
      OMG! There are roving gangs going door to door FORCING people to get vaccinated!
      • (Score: 2) by DannyB on Monday July 19, @07:58PM (1 child)

        by DannyB (5839) Subscriber Badge on Monday July 19, @07:58PM (#1158003) Journal

        Ug, forgot to use proper markup. Let me try that again . . .

        Answer: from the part you quoted, I would say pressurization is to somewhere <= 8,000 feet. (2438.4 meters)

        --
        OMG! There are roving gangs going door to door FORCING people to get vaccinated!
        • (Score: 0) by Anonymous Coward on Tuesday July 20, @10:40AM

          by Anonymous Coward on Tuesday July 20, @10:40AM (#1158211)

          I know this is completely off topic, but this, dear friends, is why "sanitizing" input is the wrong approach.

    • (Score: 2) by Beryllium Sphere (r) on Monday July 19, @08:06PM (2 children)

      by Beryllium Sphere (r) (5062) on Monday July 19, @08:06PM (#1158010)

      I believe that means the cabin pressure is the same as you'd have at the top of an 8,000 foot mountain. They could design it to go all the way to sea level pressure but that's a lot of force on the structure that's not required for humans to breathe.

      So you go along at 37,000 feet, but bleed air from the engines puts as much pressure in the cabin as you'd get in an open plane at 8,000 feet.

      • (Score: 2) by sjames on Tuesday July 20, @02:31AM

        by sjames (2882) on Tuesday July 20, @02:31AM (#1158136) Journal

        Unless it's a 737 with faulty switches, then, who knows?

      • (Score: 0) by Anonymous Coward on Tuesday July 20, @04:47AM

        by Anonymous Coward on Tuesday July 20, @04:47AM (#1158163)

        The cabin pressure is adjustable. The pilots program in the starting altitude, the cruising altitude, and the destination altitude. The cabin pressure slowly decreases until hitting the programmed altitude pressure. As you start the decent, the pressure slowly builds back up until it matches the pressure on the ground.

        Thankfully this pressure problem is only for the 10,000 warning system. There is a redundant 14,000 foot system that works slightly differently that would also warn the pilots and cabin crew if the primary system fails.

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