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Aeroflot Superjet 100 fire and evacuation at UUEE

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  • #16
    Two new videos uploaded in AvHerald.

    One showing the vary rough final bounce (corded from a TV, so not good quality, but it can still be appreciated that it was really rough and, while I would understand the landing gear failing, I don;t understand 50%+ of the people on board dying).

    The second one is the final seconds of the landing roll recorded from the cabin by a pax sitting next to the wing. You can see the fire out of the window and the cabin staring to fill up with smoke. Perhaps it was the smoke, not the fire, what initially disabled the passengers who could then not escape.

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

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    • #17
      A better view of the bounce and start of the fire

      https://twitter.com/RALee85/status/1125 ... 97/video/1

      --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
      --- Defend what you say with arguments, not by imposing your credentials ---

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      • #18
        Originally posted by Gabriel View Post
        A better view of the bounce and start of the fire

        https://twitter.com/RALee85/status/1125 ... 97/video/1
        Maybe it's just because the video quality is so bad, but it appears to me that the main gear is missing after the first bounce and that the plane coms down hard on the engine nacelles just before the fuel cloud and fire appear. The SSJ has those long engine pods that extend further under the wing. Perhaps they breached the tanks.

        https://edition.cnn.com/2019/05/05/e...ire/index.html

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        • #19
          Yes, main gear went through the wings and tanks after first hard contact, setting everything on fire.

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          • #20
            Originally posted by Gabriel View Post
            The fire should not have gone into the cabin so easily. Unless the landing was harder than I think and the fuselage itself broke.
            I think the landing was harder than you think.

            Evidence: A very large fire that went into the cabin.

            If you hit hard enough, there's things besides the landing gear that rupture fuel tanks. (Evan's nacelles included)

            Originally posted by Gabriel View Post
            Perhaps it was the smoke, not the fire, what initially disabled the passengers who could then not escape.
            ...or impact injures...The 90-second evacuation is usually done with healthy, mobile folks who are mentally prepared, in a not_smoke-infested cabin, AND not really in danger, since it's usually a simulation.
            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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            • #21
              Originally posted by Alex - Spot-This ! View Post
              Yes, main gear went through the wings and tanks after first hard contact, setting everything on fire.
              No, the breach occurs after the last impact, but before the last impact, it **appears** that the MLG is either detached or collapsed (or never extended), when there is still no fuel tank breach.

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              • #22
                Originally posted by Evan View Post
                No, the breach occurs after the last impact, but before the last impact, it appears that the MLG is either detached or collapsed (or never extended), when there is still no fuel tank breach.
                Maybe it's a trick of the low-res video, but have a closer look.

                https://www.youtube.com/watch?v=HG3_clcQIFI

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                • #23
                  Videos from inside the cabin show how main gear went through the wing and remained there for the entire landing

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                  • #24
                    Originally posted by Evan View Post
                    No, the breach occurs after the last impact, but before the last impact, it **appears** that the MLG is either detached or collapsed (or never extended), when there is still no fuel tank breach.
                    You know what... forget it. That video is too lowres to determine anything.

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                    • #25
                      Whatever the cause, a bounced landing like this shouldn't result in a breached fuel tank (or a broken wing spar). The DC-10/MD-11 had a problem with this (see Gabriel's previous post) and lessons were learned. Hopefully the investigation will focus on this.

                      The wings:

                      The SSJ wing has the second highest aspect ratio after the B787. Pains were taken to achieve this. The wing was optimized for cruise level flight.

                      The gear:

                      Originally posted by Alexey Dolotovski, Deputy Chief Designer (Aerodynamics) at SCAC
                      We have a durable landing gear, excellent double-strut gear legs, a real work of art. They are able to endure the roughest landing without any damage. Of course double-strut landing gear is heavier than a single-strut one. But when a single-strut landing gear is mounted on the aircraft it turns out that the hinge fittings need to be reinforced. As it turned out the single-strut landing gear together with reinforced hinge fittings are heavier than double-strut landing gear. Our landing gear has lower weight as compared to the single-strut one installed on Embraer 190.

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                      • #26
                        Originally posted by Alex - Spot-This ! View Post
                        Videos from inside the cabin show how main gear went through the wing and remained there for the entire landing
                        Link please?

                        --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                        --- Defend what you say with arguments, not by imposing your credentials ---

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                        • #27
                          The MLG-to-wing setup:
                          Click image for larger version

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                          • #28
                            We have a durable landing gear, excellent double-strut gear legs, a real work of art. They are able to endure the roughest landing without any damage.
                            1- Depending on how you define "the roughest landing", this can actually be a bad thing. In the same way than super solid cars that would remain almost intact after a crash but with the occupants smashed inside.
                            2- And it has just been proven wrong, unless this landing was rougher than the roughest one.

                            --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                            --- Defend what you say with arguments, not by imposing your credentials ---

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                            • #29
                              Originally posted by Gabriel View Post
                              1- Depending on how you define "the roughest landing", this can actually be a bad thing. In the same way than super solid cars that would remain almost intact after a crash but with the occupants smashed inside.
                              2- And it has just been proven wrong, unless this landing was rougher than the roughest one.
                              And it's not the first time the MLG has collapsed on landing.

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                              • #30
                                Originally posted by Gabriel View Post
                                Well, it shouldn't. Fuse pins are there to prevent that hard landing loads transfer to the wing spar which then acts like a fuse itself. Like in the several DC-10 and MD-11 hard landing accidents where one of the wings pars failed, the airplane lost that wing, and the plane rolled inverted engulfed in flames. A fuse pin is NOT there to prevent the landing gear strut from going through the wing tanks, rather the opposite, sort of. The compression fuse pin is supposed to fail under high landing gear compression stress and let the strut go through the wing, except that there should be no fuel tank there because the landing gear assembly is located behind the rear spar which is the aft end of the fuel tank.

                                I suppose that the British Airways 777 accident at Heathrow was a quite harder landing.
                                25 ft/s (1500 ft/m)

                                That accident, being at a high descent rate on soft surface, imposed very high loads both in compression and backwards. One landing gear failed under compression while the other failed under backwards force. One of the fuel tanks (don't remember which one) was protected as per design, the other one was breached because a secondary rod (that gives stability to the assembly) failed to fail as designed, and penetrated the fuel tank. Luckily the soft and wet ground helped avoid a fire.
                                Actually, both MLG failed by design for upward compression (the outboard fuse pin failed on both of the main landing gear beams). I was wondering how a vertical compression fuse pin would work, expecting it at the trunnion, but it is actually at the gear beam (an airframe attachment structure) outboard attachment.

                                The left wing tank was breached a bit between the upper wing skin and the rear spar. The center tank was breached when the right gear rotated inward and the drag brace tore off the rear spar web along with part of the center tank wall. The right gear then detached, striking and penetrating the aft fuselage, breaching the oxygen cylinder manifold (venting the oxygen, thank god there was no fire) and then went airborne, striking the horizontal stabilizer.

                                The fuel pipes also fractured, spilling fuel until the spar valves closed.

                                But that is all to be expected from a 777 falling out of the sky. Fuel tanks should be protected against the kind of rough landing we saw yesterday.

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