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  • Can I suggest a slightly different way of looking at this?

    IMHO, part of the explanation for things like this is people's belief in "Murphy's law": that anything that *can* go wrong, *will* go wrong.

    I personally think Murphy's law is false and misleading: most of the time what *can* go wrong will *not* go wrong. Fail to check the oil in your 172 before going flying? 99% of the time you'll be fine. Get drunk and go out driving? 9 times out of 10 you'll get home safely... then of course there's the 10th time when the whole world changes. Do you think anyone would ever drive drunk if there was a 100% possibility that something would go wrong as a result?

    I think the same applies in the situation being discussed here. 99% of the time that pilots attempt to fly through a "questionable" area of weather, they get away with it. And it's human nature to focus on the 99% and think that you'll get away with it this time too, even though "this time" may be the other 1%...
    Be alert! America needs more lerts.

    Eric Law

    Comment


    • Originally posted by elaw View Post
      Can I suggest a slightly different way of looking at this?

      Fail to check the oil in your 172 before going flying? 99% of the time you'll be fine. Get drunk and go out driving? 9 times out of 10 you'll get home safely...

      I think the same applies in the situation being discussed here...
      Part of me wants to argue that you are wrong- and part of me says you are right.

      I don't like the oil analogy...even if you are flying through a NON thundershower, you can expect wind gusts and down drafts and wind shears and need to be "on your game" in controlling the plane- cheating on the oil is cheating...landing in any rainshower should have your game turned up at least a notch.

      On the other hand- you really really nail it! Forget the rain- an extreme cold front has passed...it's crystal clear and major blustery! Do we close the airport because there's 20 knot winds gusting to 30? How about 30 gusting to 40? 40, gusting to 50 but straight down the runway???

      A wind gust is a wind gust and if you are a professional pilot, you PRIDE YOURSELF on your ability to handle wind!

      And 95% of the thunderstorms generate winds that are well within the range of a pilots and planes ability. And we do usually (but not always) shut down for genuine severe thunderstorms.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • Yeah, I agree the oil analogy isn't perfect. Although if you depart on a flight in a 172 with insufficient oil in the engine, it's likely a point will come where you'll need to be "on your game" or that flight is going to have a very bad outcome.
        Be alert! America needs more lerts.

        Eric Law

        Comment


        • Originally posted by 3WE View Post
          Do you blame the Delta 191 pilots for bad decision making?
          No, based on the information they had which was highly limited, circumspect and incomplete.

          Do you blame the ATC/Weather systems for conveying information that's a bit limited and slow?
          This is a grey area, a lot of balls were dropped here. But it ties in to your first and third points.

          Do you blame 'no one' because rare things sometimes align really badly in spite of our best effots?*

          (*It should be noted that what we know and do now is different from what we knew and did back in 191's days...until you look at AA 1420)
          This incident was a confluence of factors which gelled perfectly (or badly) to its final outcome.

          Comment


          • Originally posted by elaw View Post
            Can I suggest a slightly different way of looking at this?

            IMHO, part of the explanation for things like this is people's belief in "Murphy's law": that anything that *can* go wrong, *will* go wrong.
            If you keep trying, it *will* eventually go wrong.

            --- 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


            • Give all of that:

              Do you blame the Delta 191 pilots for bad decision making?

              Do you blame the ATC/Weather systems for conveying information that's a bit limited and slow?

              Do you blame 'no one' because rare things sometimes align really badly in spite of our best effots?*
              I really don't like 'Blame', because you can only deal with the knowledge and training you have, and the information you receive.

              They were dealing with old generation weather radar which wasn't anywhere near what we have today. They didn't have predictive or reactive windshear alerting. They wouldn't have known about microbursts, because the industry didn't know. They weren't given real time information about wind/weather conditions at the airport, partly because of lax-ness, but partly because the importance of that information wasn't understood.

              We've moved on from there. If the same accident occurred today, I'd be heading far more towards the B word.

              Comment


              • Originally posted by MCM View Post
                You never consciously "accept a risk" and be done with it - its a constant state of monitoring and 'situational awareness'. If you become unhappy with the situation, whatever it may be, you take action.

                I'm sure this is true of yourself and hopefully most pilots out there, but there is that get-there-itis that we keep hearing about after these tragedies. There seems to be a committed state of mind once the decision to land has been made that clouds situational awareness. I also think 25kts over Vref at 800ft is unstabilized and should make you unhappy with the situation. It seems to me like Delta 191 had a fair chance to break away at that point and chose to continue beyond the realm of reasonable risk.

                Comment


                • We'll have to disagree there Evan.

                  A temporary increase to VREF + 25 at 800ft is NOT unstable and does not meet most airlines definition of unstable. Gusting conditions can cause that, and as long as the flight path, thrust and rate of decent were reasonable, the approach is stable. I'd have done dozens of missed approaches if that were a hard rule, all for no reason whatsoever. This is why we have to use discretion.

                  The manner in which you attained that speed, however, could meet the definition of windshear. That is what you are really looking for. There is a difference in gusty conditions increasing to that speed, but averaging a reasonable value, and going from on speed to +25 sustained due to a thunderstorm, when you are likely to fall out of it again at an inopportune moment.

                  Of course they could have given it away at 800ft, and if there was lightning and heavy rain, there's pretty good reasons to do so! We also understand a lot more about what the consequence of an increase in headwind associated with a storm is likely to lead to.

                  Being VREF + 25 at 50 ft is another story.

                  As to press-on-itis... yes, thats an issue. More so, I'd say its task fixation. The worse the condition, the more likely the PF is working very hard on just flying, and so gets fixated on what he is doing.

                  I'm really not sure the fuss though - we really aren't seeing large numbers of windshear/thunderstorm related crashes these days are we?

                  Comment


                  • Originally posted by MCM View Post
                    ...I'm really not sure the fuss though...
                    1) You have to factor in the layman-aviation-forum-parlour-talk factor.

                    2) We have the confict of you and Bobby making relatively bold statements about your storm avoidance, yet landings take place in storms- we see youtubes, we see Gabriel stats, we see AA 1420, and you have me being a pain as I watch air traffic during storms and claim that "you guys" kind of push it.

                    3) There's also the conflict of "you" saying it's not a clear decision process. And, I get that and that: There isn't an magical fix.

                    BUT

                    The counter argument is that foffies are never comfortabe "just" relying on your judgement...and when it's "just" judgement, then those intangible things sneak in: duty time, whether your diversion will ROYALLY FUBAR the plane positioning or not. Will the alternate airport have a gate available, or do you make the news for imprisoning your passengers?

                    While Evan is going to push strongly for clear cut processes, I'm going to quietly wish that there could be a clear cut, 100% dependable wind shear avoidance procedure.

                    4) Finally, we have the calculated risk issue (elaw): The difference between a mean thunderstorm and a strong cold front is actually kind of gray: That plane tht ran off the runway at Denver a few years ago in gusty weather with light snow, scraped wing tips in Germany, and what happenes to you on short final with a storm 8 miles away with an approaching gust front...all are an elevated risk compared to a sunny California evening with gentle winds, where apparently it can be hard to manually land a 777.

                    5) Go back and read #1.
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • Originally posted by MCM View Post
                      We'll have to disagree there Evan.

                      A temporary increase to VREF + 25 at 800ft is NOT unstable and does not meet most airlines definition of unstable. Gusting conditions can cause that, and as long as the flight path, thrust and rate of decent were reasonable, the approach is stable. I'd have done dozens of missed approaches if that were a hard rule, all for no reason whatsoever. This is why we have to use discretion.

                      The manner in which you attained that speed, however, could meet the definition of windshear. That is what you are really looking for. There is a difference in gusty conditions increasing to that speed, but averaging a reasonable value, and going from on speed to +25 sustained due to a thunderstorm, when you are likely to fall out of it again at an inopportune moment.
                      Timeline:
                      1- They see the dark cloud and heavy rain ahead (they mention something about washing the plane).
                      2- They see the lighting coming from that cloud.
                      3- The FO flies a very stabilized approach, including a very stable speed.
                      4- There is a sudden huge increase in airspeed.
                      5- The FO says "Idle".
                      6- The captain says "No, you are going to lose it all of a sudden".
                      7- They are hit by a strong downdraft and they do "lose the airspeed all of a sudden indeed".
                      8- The FO manages to follow the localizer very well, which under these conditions of course implies raising the nose a whole lot.
                      9- The plane is hit by a strong updraft.
                      10- Since the AoA was already high, that updraft generates a split-second stickshaker activation.
                      11- The FO responds to that stickshaker activation by pushing down way too much, putting the plane in negative Gs and shoving the nose down, thus effectively putting the plane in a dive.
                      12- The captain says Go around.

                      I'd say that, with the current knowledge, practices and training, they should have gone around at 3, or 6 the latest. Having failed to do that, 8 would have been another good opportunity with the knowledge and training that they had back then, and even 12 was still doable.

                      The accident was technically preventable at any point before actually hitting the car. By then the plane was flying horizontally, with a low AoA, a good airspeed, and speeding-up very well under TOGA thrust. There was a lot of reserve performance to go up and 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 ---

                      Comment


                      • Originally posted by Gabriel View Post
                        Timeline:
                        1- They see a mundane towering cumulus summer afternoon thundershower ahead (they mention something about washing the plane).
                        2- They see the lighting coming from that cloud.
                        3- The FO flies a very stabilized approach, including a very stable speed.
                        4- There is a sudden huge increase in airspeed.
                        5- The FO says "Idle".
                        6- The captain says "No, you are going to lose it all of a sudden".
                        7- They are hit by the strongest downdraft and wind shear ever reported and they do "lose the airspeed all of a sudden indeed".
                        8- The FO manages to follow the localizer very well, which under these conditions of course implies raising the nose a whole lot.
                        9- The plane is hit by a strong updraft.
                        10- Since the AoA was already high, that updraft generates a split-second stickshaker activation.
                        11- The FO responds to that stickshaker activation by pushing down way too much, putting the plane in negative Gs and shoving the nose down, thus effectively putting the plane in a dive.
                        12- The captain says Go around.
                        Fixed.

                        I only disagree with the arm-chair aspect...if you are getting your butt kicked by severe turbulence and the stall horn goes off, an unfortunate gut reaction might be a good-healthy shove.*

                        A man named Gabriel once said, it's almost always better to crash under control.

                        *We do seem to have fixed that good healthy shove thing... (Cue the long Gabriel list of which includes Colgan and Air-France...)
                        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                        Comment


                        • All I know is that in 1994 I was in a B737 of Saudia at night on long finals into Riyadh when the Captain announced that there was huge storm and threats of wind shear over the airfield and that he wasn't even going to take a closer look, never mind try for a landing and that he was going to divert to Dhahran. That pleased the two oilmen sitting in front of me as Dhahran was their final destination anyway and, as we turned away from Riyadh it pleased me as well because we were treated to the sight of the most violent storm I have ever seen. 3 hours later we were back and on finals into Riyadh having been treated to the best fireworks show ever seen from the storm cells on the way back from Dhahran. Finals into the landing was still an experience with a huge crosswind that offered me a view of the runway all the way down to touchdown. The pilot earned his money and the applause that he got that night.
                          The biggest lesson for me though that night was the utter violence that a storm could impart to an aircraft.....and that was the bit that we went through before the pilot decided "Allah Akhbar, I'm out of this". We were blown all over the sky with the biggest memory being my book and coffee cup hovering in mid air !
                          Last edited by brianw999; 2014-03-04, 15:02.
                          If it 'ain't broken........ Don't try to mend it !

                          Comment


                          • Originally posted by brianw999 View Post
                            All I know is that in 1994 I was in a B737 of Saudia at night on long finals into Riyadh when the Captain announced that there was huge storm and threats of wind shear over the airfield and that he wasn't even going to take a closer look, never mind try for a landing and that he was going to divert to Dhahran. That pleased the two oilmen sitting in front of me as Dhahran was their final destination anyway and, as we turned away from Riyadh it pleased me as well because we were treated to the sight of the most violent storm I have ever seen. 3 hours later we were back and on finals into Riyadh having been treated to the best fireworks show ever seen from the storm cells on the way back from Dhahran. Finals into the landing was still an experience with a huge crosswind that offered me a view of the runway all the way down to touchdown. The pilot earned his money and the applause that he got that night.
                            The biggest lesson for me though that night was the utter violence that a storm could impart to an aircraft.....and that was the bit that we went through before the pilot decided "Allah Akhbar, I'm out of this". We were blown all over the sky with the biggest memory being my book and coffee cup hovering in mid air !
                            Brian, I am sure you have heard this old saying before.

                            There are old pilots, and there are bold pilots. But there are no old bold pilots!

                            Old sayings are usually old sayings for a good reason! As we get older we usually figure out that almost everything our parents told us to help us out was TRUE! Even though we didn't think they knew shit!!

                            Comment


                            • Originally posted by BoeingBobby View Post
                              Brian, I am sure you have heard this old saying before.

                              There are old pilots, and there are bold pilots. But there are no old bold pilots!

                              Old sayings are usually old sayings for a good reason! As we get older we usually figure out that almost everything our parents told us to help us out was TRUE! Even though we didn't think they knew shit!!
                              ...and in the meantime, young, less wise pilots occasionally kill off a load of passengers.
                              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                              Comment


                              • Originally posted by 3WE View Post
                                ...and in the meantime, young, less wise pilots occasionally kill off a load of passengers.

                                My recommendation to you at this point is to buy yourself a lifetime rail pass.

                                Oh wait a second, they fuck up and kill people every once in a while too!

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