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Very hard landing Boeing 737-800

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  • Very hard landing Boeing 737-800

    Landing at the Krakow airport on the Boeing 737-800 Ryanair. Video here: https://www.youtube.com/watch?v=_sulAm2yjsU
    My question is: what kind of error has occurred and the pilot made a hard landing?

  • #2
    Bounced landing... Excess vertical speed? Late, high or no flare? Wonder if they hit on the nose gear after the bounce.

    Comment


    • #3
      Here's what I think I saw on the video. The sink rate was pretty high just before the first touchdown with an obvious lack of flare. The aircraft bounced up again and the spoilers seem to be coming up while the aircraft was still airborne and then the plane came down really hard on the second touchdown. Would you all say these observations are correct?

      I have never been to Krakow, so I was wondering, which runway was used in this landing and how long it is.

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      • #4
        Spoilers but not full ground spoilers until after the second landing. The outer panel is still stowed in the air. So what is that, manual speedbrake?

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        • #5
          Originally posted by Evan View Post
          So what is that, manual speedbrake?
          That's my impression too, also because they did not deploy upon touchdown but when they were already well back airbone.

          The only explanation for that would be a "no spoilers" call from the NFP with the subsequent manual extension without the pilots realizing that they were flying. Otherwise, it's a brutality.

          --- 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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          • #6
            Looks like a bounce, followed by a manual deployment of speed brake to assist the aircraft to settle onto its wheels, without realising just how high they'd actually bounced.

            Lucky they make em tough hey!

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            • #7
              Originally posted by MCM View Post
              Looks like a bounce, followed by a manual deployment of speed brake to assist the aircraft to settle onto its wheels
              But is this a legal move? To manually deploy speedbrakes to recover from a bounce (no matter how high)? What's next? To use them if you are balooning or floating more that you wanted?

              Do you pilots know that the landing gear is designed and required to resist some 600 fpm at touchdown assuming that it only needs to take the VS from that value to zero but NOT bear the weight of the plane because the wing is supposed to be providing a lift = weight?

              --- 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 ---

              Comment


              • #8
                Originally posted by MCM View Post
                Looks like a bounce, followed by a manual deployment of speed brake to assist the aircraft to settle onto its wheels, without realising just how high they'd actually bounced.

                Lucky they make em tough hey!
                It did look like a crappy landing. As for the spoiler deployment, watch the ailerons. It appears that the aileron goes up. Any more than ten units of aileron raises the spoilers. After the guy gets the camera back up to the window, you see the spoilers at full extension. The airplane appears on the ground which would extend the spoilers normally.

                To answer Gabriel's question, there is NO WAY IN H#&L you would deploy the spoilers during a bounce. The best option is to cobb the power and go around.
                The "keep my tail out of trouble" disclaimer: Though I work in the airline industry, anything I post on here is my own speculation or opinion. Nothing I post is to be construed as "official" information from any air carrier or any other entity.

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                • #9
                  You would not extend the spoilers intentionally to recover from a bounce.

                  I don't agree that it is deployment with aileron, but thats personal opinion. It is plausible. To get that level of deployment would take a lot of control wheel turn - more than would seem likely given the aircraft's attitude.

                  I said to help it 'settle onto its wheels'. Ie, to compress the oleos and have weight on wheels. I didn't say it was a correct thing to do in a bounce - to extend the spoilers at the point that they do (if they did) would be an error. But it wouldn't be the first time it had been done.

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                  • #10
                    Originally posted by MCM View Post
                    I don't agree that it is deployment with aileron, but thats personal opinion. It is plausible. To get that level of deployment would take a lot of control wheel turn - more than would seem likely given the aircraft's attitude.
                    I need to look at the video a little more closely. Wish there was a way I could download it and go through frame by frame. It looked to me like the spoilers deployed as they would have with the ailerons. Having said that, the hard hit that causes the camera to drop below the window could be caused by spoiler deployment.

                    Originally posted by MCM View Post
                    I said to help it 'settle onto its wheels'. Ie, to compress the oleos and have weight on wheels. I didn't say it was a correct thing to do in a bounce - to extend the spoilers at the point that they do (if they did) would be an error. But it wouldn't be the first time it had been done.
                    Gabriel asked about using the speed brake lever in a bounce, so that's what my comment addressed. In the days before auto speed brakes--(back when they actually had to move the throttles by hand--gasp!)--asap after touchdown you would pull the speed brake lever to deploy the spoilers. If you were fast enough, that would compress the oleos. If you weren't fast, they were already compressed. The autospeedbrakes have increased safety, making stopping distances shorter by getting the weight on the wheels more quickly, but from a pilot's standpoint they've made landings more challenging. I should say made GOOD landings more challenging. You can roll the wheels on but when the speed brakes deploy, you drop the six or eight inches onto the struts all at once, making the landing seem harder than it is.
                    The "keep my tail out of trouble" disclaimer: Though I work in the airline industry, anything I post on here is my own speculation or opinion. Nothing I post is to be construed as "official" information from any air carrier or any other entity.

                    Comment


                    • #11
                      I should say made GOOD landings more challenging.
                      Yes its always a 'good' MEL to have on the aircraft, Auto Speedbrake.(Well, good for landing ego at least )

                      You can roll the wheels on but when the speed brakes deploy, you drop the six or eight inches onto the struts all at once, making the landing seem harder than it is.
                      I have made good use of that 'old faithful' explanation over the years, mixed in liberal measure with the backwards landing gear excuse .

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                      • #12
                        After watching it in SloMo, it doesn't look like roll spoilers at all.

                        By best shot is that:
                        1) The pilot fleared too late and too sharply.
                        2) That resulted in lift > weight but too late to arrest the descent.
                        3) Because of lift > weight the plane bounces so high.
                        4) The deflection of spoilers is (I hope) the result of the PNF calling "no spoilers" upon touchdown and the PF manually deploying the spoilers in response, not as a response to the bounce. Because the airplane was airborne the spoiler lever would not go past the flight detent.
                        5) This turned Lift > Weight into Lift <<<< Weight, and down we go!
                        6) When the plane touched back again the pilot was able to pull the lever all the way back to the ground spoiler position.

                        I have a question: Since the spoilers, once armed, will self deploy when the plane is "on ground" based on strut compression and wheel spin-up), would't them self-deploy even if the plane bounces? (the struts will compress and the wheels will spin up)

                        --- 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 ---

                        Comment


                        • #13
                          There is another option that doesn't require manual deployment.

                          Given the lack of flare, I'd say this is very plausible...

                          From 737 FCTM:

                          Bounced landings can occur because higher than idle power is maintained through initial touchdown, disabling the automatic speedbrake deployment even when the speedbrakes are armed. During the resultant bounce, if the thrust levers are then retarded to idle, automatic speedbrake deployment can occur resulting in a loss of lift and nose up pitching moment which can result in a tail strike or hard landing on a subsequent touchdown

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                          • #14
                            Originally posted by MCM View Post
                            There is another option that doesn't require manual deployment.

                            Given the lack of flare, I'd say this is very plausible...
                            From 737 FCTM:

                            Bounced landings can occur because higher than idle power is maintained through initial touchdown, disabling the automatic speedbrake deployment even when the speedbrakes are armed. During the resultant bounce, if the thrust levers are then retarded to idle, automatic speedbrake deployment can occur resulting in a loss of lift and nose up pitching moment which can result in a tail strike or hard landing on a subsequent touchdown
                            Automatic speedbrake deployment can occur while airborne?

                            Comment


                            • #15
                              Depending on the design of the auto-speedbrake system I can see that happening.

                              Assume (and this is totally assuming on my part since I don't know the design of the 737 system) the speedbrake system is designed to deploy when two conditions are met: the throttles are at idle and wheels are spinning faster than some RPM threshold.

                              So a landing is attempted and the sequence is as follows:
                              1. Pilot enters flare with throttles above idle. Speedbrake system doesn't deploy because neither condition is met.
                              2. Aircraft briefly touches down and wheels spin up. Now one condition is met (wheel speed) for the auto-speedbrakes but they don't deploy because the other condition (throttle position) is not met.
                              3. Airplane becomes airborne again.
                              4. Pilot moves throttles to idle position while plane is still airborne. The speedbrakes now deploy because both conditions are met: throttles are at idle, and wheels are spinning because they take several seconds to spin down and it's only been 0.5 second since #2.
                              5. Aircraft begins descending at a rapid rate and BAM!


                              There is however a tradeoff. The above sequence definitely has the possibility to result in a hard landing, and possible damage to the aircraft but probably not really serious damage. But if the spoiler system were designed to be more conservative in when it deploys, the result could be a long landing that takes the plane off the far end of the runway, which could have disastrous consequences.
                              Be alert! America needs more lerts.

                              Eric Law

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