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ANA 737-700 close call on Sept 6 2011

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  • #61
    Evan,

    There are a few good reasons for having rudder trim available with the autopilot engaged in the Boeing.

    For a start, it allows good engine out ability. Without being able to trim the rudder with the autopilot engaged, you would have to disconnect the a/p every time you changed the thrust setting. Not a good situation.

    A rotary switch is used because there are multiple positions required on this particular lock design. Moving it to the overhead panel might be a smart call.

    TeeVee,

    The camera is a brilliant invention. As is having the door unlocked from the inside. If you seriously can't see why it the system is designed the way it is, then you're really not thinking hard enough. I'm certainly not going to go into the specifics of the setup, but its pretty clear to see why you need the door control on the inside.

    I think yes, in hindsight, we can now see that having two switches that are of a rotate and hold design located close to each other is less than ideal. In fact they are the only two rotate and hold switches in the cockpit. I wouldn't be surprised to see them moved. But at the same time, the switches have been there for a very very long time, and this is the first time anyone has got it wrong. S$% happens sometimes.

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    • #62
      I want to be totally clear on this- I'm throwing it out as a RANDOM idea, that is not completely thought out.

      Would an "out of trim" warning system be a reasonable thing? Trim runaways have happened many times before (and not from door-latch switches)- and a little warning before the AP lets go and lets the plane kick itself into maneuvers that are "beyond the normal-category"...seems like it might be a reasonable idea?

      Not only have "trim runaways" occured, but what if the pilots simply messed up and had the plane out of trim- no foul- but not good practice either- a gentle beep and a yellow light- or B. Betty Synthetic saying "Aircraft out of trim" in an irritating voice.

      Of course, this opens up a big can of worms (including and not limited to):

      -There's already problems with warning overloads
      -And crashes caused by false warnings
      -And crashes where a good, clear, authentic warning resulted in pilots doing the wrong thing like extremely-steep, aggresive dives when there's a stall warning.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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      • #63
        Originally posted by Gabriel View Post
        On the other hand, in the A320 you can't manually deploy the spoilers after landing.
        AFAIK, you can always deploy the ground spoilers manually by pulling the speed brake lever up out of the armed position. But they will not deploy automatically in the armed position unless the thrust levers are at idle or reverse. I think not setting the levers to idle is a much larger and less understandable error though.

        About the reason for the shape and location of the controls, it seems that Boeing has three positions: Auto, open and deny (pilots are very reserved about disclosing how the system works for obvious reasons, but one can guess more or less) And in any event, the cockpit is full of switches, levers, buttons and knobs so you really can't put all buttons far away from all other buttons, all knobs away from all other knobs and so on.
        AFAIK AIrbus uses a push pull button. Pulling allows entry, pushing denies all entry for a preselected interval (disables the exterior keypad). I wonder what "auto" does on the Boeing...?

        Your amusing scenario aside, I think it just comes down to recognizing similar controls in close proximity to one another. I think either changing the type of switch or moving it to a different location on the pedestal is all that is needed.

        I see how the FBW servoloop allows the FMGC on the A320 to handle rudder trim in a way that is not possible on the 737NG, but isn't it still within the Boeing's AP capability to adjust for yaw during thrust changes in one-engine operations?

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        • #64
          Originally posted by TeeVee View Post
          so, ummm let's get this straight: you are supposed to physically turn to look at the door when unlocking it, but there is no need to look at the switch you're using to unlock the door which is why you are looking back to begin with? so looking to see who is comin through the door is more important than verifying that you yankin on the right dial?

          ok, maybe evan is right after all! the industry is doomed because it hasn't the foggiest clue how to set up proper regs.

          .....................................
          My guess is that having the monitor behind the pilots is due to the required rapid installation of locks following 9/11. When was this particular aircraft delivered and does anyone know if a more ergonomic video installation is used on newer 737 aircraft.

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          • #65
            Originally posted by TeeVee View Post
            "You've got to be a complete asshole to get those wrong."
            I think we have our explanation right there!

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            • #66
              Actually, you have to be a complete asshole to be strongly dismissive of MCM and Vnav
              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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              • #67
                G'day Evan,

                Could Boeing make their autopilots handle the rudder during all engine out activities... yes.

                Do we want them to completely handle it? I think the 777 and the older aircraft when autocoupled to the ILS have the right idea... almost trims it out (to the point it can satisfactorally fly), but is a little short of fully trimmed. The 737 is a very old aircraft, and updating the autoflight system is probably unrealistic.

                Without going into details Auto is basically just another name for "normal" on that particular switch. You could remove the word Auto and it would make no difference.

                3WE - sounds like a reasonable idea to me.

                Comment


                • #68
                  Originally posted by 3WE View Post
                  I want to be totally clear on this- I'm throwing it out as a RANDOM idea, that is not completely thought out.

                  Would an "out of trim" warning system be a reasonable thing? Trim runaways have happened many times before (and not from door-latch switches)- and a little warning before the AP lets go and lets the plane kick itself into maneuvers that are "beyond the normal-category"...seems like it might be a reasonable idea?
                  I think that an "Rudder trim in motion" warning that sounds whenever the rudder trim moves (commanded or not) would be enough. This look very simple (in avaitaion terms, where nothing is really simple let alone very): Just put the warning in parallel with the trim motor. No need of an "out of trim" warning which would be more complicated to implement. The rudder trim is seldom used anyway so it won't be annoying in normal operations. The same could be done with the roll trim, just in case. The pitch trim is already designed to be clearly noticeable when it moves: those big wheels with white straps that make a clapping and whining sound as they turn are hard to miss. And some airplanes in same cases have a specific warning sound for some movements of the pitch trim. For example, the MD-80 has a horn that sounds whenever the pitch trim moves more than a given number of degrees in the last n seconds (n was 1 or close). So, for example, if you are in AP and by mistake or inadvertently move the yoke, the AP will start to add trim against your elevator command but soon the trim horn will sound so you'll note that there are two pilots flying the plane: you and Otto. You'll also quickly recognize a trim runaway.

                  In this specific event, if the pilot attempted to open the cockpit door and receives a Ms. Douglas (ok, make that Mr. Boeing) "Rudder trim in motion" aural warning as response, he would have immediately recognized the mistake.

                  --- 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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                  • #69
                    Back to my question from earlier, I was wondering if someone could tell me what the training/requirements/policies etc. are for pilots to monitor the instruments while in cruise/AP? Are they specifically laid out? Thank you in advance.

                    Comment


                    • #70
                      Originally posted by Gabriel View Post
                      I think that an "Rudder trim in motion" warning that sounds whenever the rudder trim moves (commanded or not) would be enough...
                      Except...

                      A lot of autopilot systems work the trim (some even "fly" with the trim instead of actually moving the controls directly)- so without a "lockout" (that might fail), you'll be hearing warnings nearly constantly unless things are smooth.

                      (Just furthering the discussion).
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                      Comment


                      • #71
                        Originally posted by 3WE View Post
                        Actually, you have to be a complete asshole to be strongly dismissive of MCM and Vnav
                        you can continue with your name calling, which is probably nothing more than projecting your feelings about yourself anyway.

                        Comment


                        • #72
                          Originally posted by 3WE View Post
                          Except...

                          A lot of autopilot systems work the trim (some even "fly" with the trim instead of actually moving the controls directly)- so without a "lockout" (that might fail), you'll be hearing warnings nearly constantly unless things are smooth.

                          (Just furthering the discussion).
                          I don't think that that's the case for the rudder and ailerons.
                          And it seems to work pretty well in the MD-80 for the pitch trim, where the AP does actually use the pitch trim.
                          Maybe Nav can tell us better about this feature.

                          --- 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


                          • #73
                            UPDATE:



                            The Japan Transport Safety Board’s final report about the serious incident over the Pacific Ocean reveals there were multiple warnings of an impending aerodynamic stall, while the plane carrying 117 people exceeded its maximum operating speed a number of times. The report said the jet also exceeded its structural-load limit, or the most stress the aircraft is expected to experience in service.

                            After the co-pilot mistakenly operated a rudder-control switch at 41,000 feet, instead of a different switch that unlatched the cockpit door, the jetliner plummeted 1.2 miles in slightly more than 30 seconds and briefly flew nearly upside down. The recently released report provides some new details about the extent of the danger.


                            From the Final Report by the JTSB

                            It is highly probable that this serious incident occurred in the following circumstances: During the flight, the FO erroneously operated the Rudder Trim SW while having an intention of operating the Door Lock Selector in order to let the PIC reenter the cockpit. The aircraft attitude became unusual beyond a threshold for maintaining the aircraft attitude under the autopilot control. The FO’s recognition of the unusual situation was delayed and his subsequent recovery operations were partially inappropriate or insufficient; therefore, the aircraft attitude became even more unusual, causing the Aircraft to lose its lifting force and went into nosedive. This led to a situation which is equivalent to “a case where aircraft operation is impeded.” It is probable that the followings contributed to the FO’s erroneous operation of the Rudder Trim SW while having an intention of operating the Door Lock Selector; he had not been fully corrected his memories of operation about the Door Lock Selector of the 737-500 on which he was previously on duty; the Door Lock Selector of the 737-500 was similar to the Rudder Trim SW of the 737-700 in their placement, shape, size and operability. It is somewhat likely that his memories of operation about the Door Lock Selector of the 737-500 had not been fully corrected because he failed to be fully accustomed with the change in the location of the Door Lock Selector. It is somewhat likely that this resulted from lack of effectiveness in the current system for determining the differences training contents and its check method, under which the Company and other air carriers considered and adopted specific training programs to train pilots about how to operate the flight deck switches when their locations changed and the Civil Aviation Bureau of the Ministry of Land, Infrastructure, Transport and Tourism reviewed and approved them. It is probable that the FO’s failure to properly manage tasks contributed to his erroneous operation of the Rudder Trim SW. It is somewhat likely that the similarities between the Door Lock Selector and the Rudder Trim SW in their operability contributed to the delay in his recognition of the erroneous operation. Moreover, he was excessively dependent on autopilot flight and he failed to be fully aware of monitoring the flight condition.

                            It is somewhat likely that the FO’s recovery operations were partially inappropriate or insufficient because he was startled and confused on the occurrence of an unexpected unusual situation in which the stick shaker was activated during the upset recovery maneuver. It is somewhat likely that the followings contributed to his startle and confusion: he had not received upset recovery training accompanied with a stall warning and in unexpected situations, thereby he lacked the experience of performing duties in such situations before the serious incident, and he had not received upset recovery training at a high altitude.
                            AirDisaster.com Forum Member 2004-2008

                            Originally posted by orangehuggy
                            the most dangerous part of a flight is not the take off or landing anymore, its when a flight crew member goes to the toilet

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