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Gulfstream IV jet ran off a runway while taking off

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  • Yeah I didn't word that post very well... it wasn't really directed at you but at the group.

    It seems like much of the tone of this discussion is of the nature "what should the pilot(s) have done differently at the time of making the RTO decision?". The question I'm asking is, ignoring the benefit of hindsight, what could the pilot(s) have done differently at that time? And again ignoring the benefit of hindsight my opinion is the answer to that question is "nothing". Not enough time was allotted to make a proper decision, so they might as well have tossed a coin - which itself would be hard to do in 3 seconds. Or in other words: don't fault them for making an incorrect decision because the only way a correct one (if there even was a correct decision in this case) could possibly be made was by chance - the outcome was effectively out of their hands.

    Now whether an incorrect decision or oversight was made earlier when ample time was available - like setting the flaps incorrectly, that's a different question.
    Be alert! America needs more lerts.

    Eric Law

    Comment


    • Originally posted by elaw View Post
      Yeah I didn't word that post very well... it wasn't really directed at you but at the group.

      It seems like much of the tone of this discussion is of the nature "what should the pilot(s) have done differently at the time of making the RTO decision?". The question I'm asking is, ignoring the benefit of hindsight, what could the pilot(s) have done differently at that time? And again ignoring the benefit of hindsight my opinion is the answer to that question is "nothing". Not enough time was allotted to make a proper decision, so they might as well have tossed a coin - which itself would be hard to do in 3 seconds. Or in other words: don't fault them for making an incorrect decision because the only way a correct one (if there even was a correct decision in this case) could possibly be made was by chance - the outcome was effectively out of their hands.

      Now whether an incorrect decision or oversight was made earlier when ample time was available - like setting the flaps incorrectly, that's a different question.
      Again, you are correct in many ways, but I disagree in one thing that you don't say but imply.

      Yes, at that point in time, when a decision to go or abort must be made, chance plays a very big role. There is no way to say, until after the fact, if the decision was correct or not. If everybody walks away, the decision was correct, no matter what it was. If everybody dies, the decision was wrong, no matter what. And it is perfectly possible that there was no room for a correct decision if, at that point, no matter what decision the pilot made, everybody was going to die in one way or another. Also both decisions could be correct, if one would end with the plane happily flying and the other with the plane stopped and unscratched at either side of the end of the runway.

      But chance and flipping a coin is not the same thing. Flipping a coin is a 50/50 chance. But not all chances are 50/50. Take for example wearing a seat belt. My grand father saved his life thanks to NOT being wearing a seat belt, when his car got completely crushed in a crash and he finished lying in the floor of the car. Had he remained in his seat, he would have died. Other people saved his lives thanks to be using the sat belt. So the seat belt can save you or kill you. It's chance. However, there is overwhelming evidence that it is much more likely to save you than kill you, so chances are not 50/50. Very much like in this post-V1 go-nogo decision, it's not 20/80 or anything that adds up to 100% either, because there will be cases where you wouldn't die with or without a seat belt and cases where you will die in any case.

      In this case, there is overwhelming evidence that shows that, typically, if the plane fails to rotate at Vr, it will still rotate and fly safely later, before the end of the runway. So the question for the pilot should be: Is this one of the typical cases situation or we are in an exception? And here the pilot has to make a judgement call.

      So, while we can't say if the decision was correct or incorrect until after the fact, what we can judge is if the decision was reasonable or not. That is if, with the information and context that the pilot had at the time, the decision taken was one that a reasonable, well trained pilot would take.

      And here, a decision can be reasonable (or not reasonable) regardless of the outcome. Take for example the Teterboro crash. The plane was a bit overweight, with its CG quite forward of its forward limit, and the trim in a "normal" take-off position that was not good at all for this take-off condition. The pilots didn't know all that so that can't be a part in the reasonability judgement. So they accelerated, the acceleration felt normal, all the engines and systems were working ok, V1, rotate, but the plane won't rotate. Try harder for a few more seconds, and the plane won't rotate. The end of the runway is approaching, we are dozens of knots past V1 and Vr.

      It is reasonable that a pilot might expect that, if the plane hasn't rotated by dozens of knots past Vr, it will not rotate, so better abort now. It will be a hell of an overrun, but not as fast as if we keep trying until we hit something.
      The decision to abort is reasonable, no matter the outcome that will be known only in hindsight.
      And this is the decision that they took. The plane overrun the runway, crossed a 10-lane highway, impacted a vehicle (seriously injuring its occupants), crossed a parking lot, crashed with a building and caught fire. All the occupants of the plane walked away, not unscratched, but walked, literally. As you can see, chance played a very big role in their survival.

      It is also reasonable that the pilot might think that, even if the plane hasn't rotated until now, it can still rotate before the end of the runway as it's typically the case in this type of incidents and that, while the consequences of being wrong are almost surely lethal, it's much more likely that we'll not be wrong, so better let's not face a hell of an overrun that, while not so much as being wrong, holds a good chance of being lethal too. So if the pilot had decided to continue with the take-off, it would have been a reasonable decision too. Again, no matter the outcome.
      Again in hindsight, while the pilot did not take this decision, we know what would have happened. The pilot started to abort at 160kts. Exactly the same speed at which the plane would have started to rotate indeed, had the pilot kept trying. And after that, the plane would have lifted off and flown with no problem.

      Any relation between Teterboro and the occurrence of this thread is a mere coincidence. Or maybe not?

      In the case of this thread, we don't know what happened or what the pilot knew of what was happening. So we cannot judge the reasonability of his decision to abort yet. We know that it didn't work so, in hindsight, the decision was not correct. We don't know if a decision to continue would have worked either. Maybe there was no correct decision that could be made at the point where he took the decision.

      Based purely on history and what these cases typically are, I suspect that we'll eventually learn that the plane would have been able to fly had the pilot kept trying a bit longer. But it could be an exception to the norm too.

      --- 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


      • Originally posted by Gabriel View Post
        Take for example the Teterboro crash.
        One thing the pilot might have been considering in that instant is that Teterboro is situated in a dense urban area and if the a/c proved uncontrollable in the air it might have been more than the occupants of the plane at stake. In that instant I doubt he could have speculated as to the reason for the failure to rotate, aside from the fact that something was very wrong....

        That flight had a COG problem at least somewhat due to tankering. That is why I speculated about this early on. This flight was light on pax and only needed to be fueled for a short hop so if they were heavy I wonder what was the source of that weight.

        What other reasons would prevent rotation? Was a walkaround performed? Were the checklists skipped over? This one is certainly a head scratcher...

        Comment


        • Originally posted by Evan View Post
          What other reasons would prevent rotation? Was a walkaround performed? Were the checklists skipped over? This one is certainly a head scratcher...
          A rock kicks up and jams the elevators.
          Trim runaway
          "Broken jackscrew"
          Fancy hydraulic actuator goes into "reverse mode"
          The bolt holding something fell out
          Hose broke
          Pilot has heart attack and slumps over the wheel (or shoves forward in pain) at exactly the wrong time.
          Murdersuicidesometing
          Distruntled worker hiding somewhere comes out and shoots pilots
          The ever-relevant default that we might have to wait for the final report.

          While this seems strange- pretty much all plane crashes are strange and control problems aren't uncommon.

          Edit. I forgot control locks that I stupidly asked about... Maybe during the control check they ripped the brackets off the push rods because the elevators were locked.
          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

          Comment


          • Added to all that...

            Pilot to first officer...." Naaah, we don't need to do a walk around. We've already done two short flights today and everything was fine. What can change ?

            Part of the insidious development of a disaster ?
            If it 'ain't broken........ Don't try to mend it !

            Comment


            • NTSB preliminary report is out and can be viewed here: http://www.ntsb.gov/aviationquery/br...31X32035&key=1

              They seem to be going in the direction of blaming the gust lock system, but also say no control check was done before the takeoff was attempted.
              Be alert! America needs more lerts.

              Eric Law

              Comment


              • The airplane was equipped with a mechanical gust lock system, which could be utilized to lock the ailerons and rudder in the neutral position, and the elevator in the down position to protect the control surfaces from wind gusts while parked. A mechanical interlock was incorporated in the gust lock handle mechanism to restrict the movement of the throttle levers to a minimal amount (6-percent) when the gust lock handle was engaged.

                The FDR data revealed the elevator control surface position during the taxi and takeoff was consistent with its position if the gust lock was engaged. The gust lock handle, located on the right side of the control pedestal, was found in the forward (OFF) position, and the elevator gust lock latch was found not engaged.
                It says the gust lock would lock the elevator "in the down position" - would that mean the fully down position?

                If that were the case I'd think it would be pretty obvious to the pilots that there's a problem because the yokes would be fully forward and stuck there.
                Be alert! America needs more lerts.

                Eric Law

                Comment


                • Okay, you totally lost me with that one...
                  Be alert! America needs more lerts.

                  Eric Law

                  Comment


                  • What of the most basic of cockpit check before, starting out with the yoke: fore and aft, left and right? Seems it would fail the pilot pulling back and forth.
                    Live, from a grassy knoll somewhere near you.

                    Comment


                    • Originally posted by elaw View Post
                      Okay, you totally lost me with that one...
                      See post #31 in this thread.

                      Someone keeps coming up with with really interesting and relevant information that the rest of the parlour-talking ass hats dismiss.

                      (and someone else asked a stupid question back in the high 20's)

                      I was cheering for those folks insight and contributions.
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                      Comment


                      • Originally posted by guamainiac View Post
                        What of the most basic of cockpit check before, starting out with the yoke: fore and aft, left and right? Seems it would fail the pilot pulling back and forth.
                        What of the most basic rules says don't pull up relentlessly?

                        What of the most basic rules says check airspeed regularly- and maybe even more than that as you approach "the fence"?

                        (I also wonder- just a bit- if it's possible that they did do the "controls free" check and blew some hose or ripped off a bracket/busted a pin, bent a push rod...stranger things have happened)
                        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                        Comment


                        • Well, elsewhere in the report it specifically states they did not do a control check... or more specifically, that movement of the flight controls normally associated with a control check was not recorded on the FDR.

                          I honestly don't quite know how to interpret the last part of that blurb I posted - where it says "The gust lock handle...was found in the forward (OFF) position, and the elevator gust lock latch was found not engaged."

                          It's clear from what they say that the gust lock thingy (to use the technical term) in the cockpit was "off". But the "gust lock latch"... is that the actual part that locks the elevator? If so, and it was not engaged, is it possible that the elevator's lack of motion was caused by something else and it's just a coincidence it stayed in the position normally associated with the gust lock?
                          Be alert! America needs more lerts.

                          Eric Law

                          Comment


                          • That's my point, regardless of a cockpit position switch, it blows my mind that they didn't "box the stick or yoke" before takeoff. That is something that is so hammered in that it should be done almost without conscious thought.

                            Granted, I never flew anything near that complex with detailed checklists but the only exclusion I can think of is a tour operator where the pilot never shuts down or is out of his seat, like in the "penny a pound" 2 minute flights for kids.
                            Live, from a grassy knoll somewhere near you.

                            Comment


                            • Even if the yokes were locked down when exactly did these dummies actually put hands on them , 150kts ? I'm not buying it .

                              Everyone knows you gotta, " pull up the whole time" .

                              Comment


                              • 3WE makes an interesting point indeed. Is this surface fly-by wire, hydraulic or the old cable and turn-buckle system? Either way, the yoke may have functioned but have been jammed but appeared to be free.

                                Also jut wondered what gust locks were made of and could they have disappeared in a hot fire?
                                Live, from a grassy knoll somewhere near you.

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