Announcement

Collapse
No announcement yet.

737 gear collapse

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • 737 gear collapse

    Accident: Malaysian B734 at Kuching on Oct 2nd 2009, gear collapse at the gate
    By Simon Hradecky, created Monday, Oct 5th 2009 06:45Z, last updated Monday, Oct 5th 2009 06:58Z

    9M-MMR on air cushions (Photo: Michael Chai)
    A Malaysian Airlines Boeing 737-400 registration 9M-MMR had arrived from Kuala Lumpur (Malaysia) and was waiting at Kuching's (Malaysia) gate 05 for the departure to Kuala Lumpur, when the left inner wing spar structure gave way permitting the left main gear to tilt out of position leaving the airplane resting on the nose gear, right main gear and the left hand engine. Parts of the assembly were pushed through the upper surface of the wing. The airplane sustained substantial damage, no injuries occured.


    Damage seen from the gate (Photo: Michael Chai):



  • #2
    The airplane in question was delivered 3/93 and is approaching 40,000 flight cycles and hours, which is middle-aged for a 737.

    Based on the description, it is doubtful the wing's rear spar "gave way" as described in the article. More likely the fuse pin at the outboard end of the main landing gear beam failed. The fuse pin is located in a structural assembly nicknamed the doghouse fitting, which is attached to the rear spar of the wing. The fuse pin is designed to fail in the event of an extreme hard landing, allowing the main landing gear to safely break away from the airplane and preventing the fuel tanks inside the wing box from rupturing.

    Loads on the gear while the airplane is sitting on the ground are relatively small compared to landing loads. A likely scenario is that the fuse pin had been previously damaged, and corrosion developed at the fracture face. Over time the pin weakened to the point where it failed under static load.

    Another possibility is that the fuse pin at the forward trunnion fitting failed, but without a photo this can't be determined. Regardless of which pin failed, the main landing gear support structure will blow through the upper fixed trailing edge panels. While appearing very dramatic, the main wing box should be left virtually undamaged.

    Comment


    • #3
      Thanks, Verbie! Very reassuring as I'll be flying Malaysian SIN-KUL end of month. Then again I haven't bothered to check the make of the thing, a Boeingbus Md-367 I'm sure.
      Per
      Ancient Mariner
      Certified above and below...................sea level.

      Comment


      • #4
        Keep your seatbelt fastened at all times, Per. Even if the airplane is just sitting at the gate.

        Comment


        • #5
          Based on what I see in this photo, it is the forward trunnion that failed.



          The forward trunnion fuse pins are designed to fail in what is called a drag overload condition. This has nothing to do with David's sartorial preferences; rather, it allows the gear to break away from the wing (and its fuel tanks) if the landing gear hits something immovable (a berm, really deep mud, etc.).

          Edit. Seeing as the gear rolled forward rather than backward, we should entertain the possibility that the gear was rammed from behind (easy now, Dale) by some ground equipment.

          Comment


          • #6
            Originally posted by Verbal View Post
            Based on what I see in this photo, it is the forward trunnion that failed.



            The forward trunnion fuse pins are designed to fail in what is called a drag overload condition. This has nothing to do with David's sartorial preferences; rather, it allows the gear to break away from the wing (and its fuel tanks) if the landing gear hits something immovable (a berm, really deep mud, etc.).

            Edit. Seeing as the gear rolled forward rather than backward, we should entertain the possibility that the gear was rammed from behind (easy now, Dale) by some ground equipment.
            Typical, blame it on "rampie error"

            Comment


            • #7
              Originally posted by Robert Hilton View Post
              Typical, blame it on "rampie error"
              Works for me.

              Comment


              • #8
                Originally posted by Verbal View Post
                Keep your seatbelt fastened at all times, Per. Even if the airplane is just sitting at the gate.
                I try to have toilet business before I go through the front left door. So if you arent on long haul, maybe you are belted from entering her (B738 etc ) until the doors open for arrival.
                "Today, we stop shouting." yes. Finally! I love it.
                The Gold Member in the 747 club, 50 years since the first LH 747.
                And constantly advanced, 744 and 748 /w upper and lower EICAS.
                Aviation enthusiast, since more than 35 years with home airport EDDL.

                Comment


                • #9
                  Originally posted by Verbal View Post
                  Keep your seatbelt fastened at all times, Per. Even if the airplane is just sitting at the gate.

                  I'll make sure I start wearing the seatbelt in the bar. Must have a starter considering it is a 06:45 hrs from SIN. Yaaaawwnnnn.
                  Per
                  Ancient Mariner
                  Certified above and below...................sea level.

                  Comment


                  • #10
                    Originally posted by Robert Hilton View Post
                    Typical, blame it on "rampie error"
                    Normally we blame the dead pilots.
                    Oh wait ... sorry ... no Airbus.

                    And the old question: what happens when you pull the landing gear lever while standing on the ground?

                    Comment

                    Working...
                    X