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  • tick tock tipms topms

    http://avherald.com/h?article=4ac18a5b&opt=0
    (BB, note TORA is mentioned. I told you I didn't made that up)

    "On 21 July 2017 at 1539 hrs, C-FWGH took off from Belfast International Airport with a thrust setting which was significantly below that required for the conditions of the day. Preliminary evidence indicated that, after the aircraft lifted off from the runway, one of the aircraft tyres struck a runway approach light, which was 35 cm high and 29 m beyond the end of the runway."

    The AAIB reported that neither UK's Civil Aviation Authority not the AAIB had been informed about the occurrence by captain, operator or tour operator although the Canadian TSB had been informed about the occurrence. ATC filed a Mandatory Occurrence Report which was not read by the AAIB until Jul 24th, as result the data off the flight fata and cockpit voice recorders were not available to the investigation as the aircraft had flown 16 sectors in the meantime and the data of the occurrence flight on both flight data and cockpit voice recorders were overwritten.

    The AAIB reported: "The crew were cleared for takeoff on Runway 07 from Taxiway D (Figure 1), which gave a Takeoff Run Available (TORA) of 2,654 m. During the takeoff, at around 120 to 130 kt, the crew realised that the aircraft was not accelerating normally. They estimated, during post-flight interviews, that they reached V1 1 with around 900 m of the runway remaining and rotated shortly afterwards. The aircraft was seen, by multiple witnesses, during rotation and took a significant time to lift off before climbing at a very shallow angle. ... After takeoff, the crew checked the aircraft’s FMC which showed that an N1 of 81.5% had been used for the takeoff. This figure was significantly below the required N1 setting of 93.3% calculated by the operator and shown on the pre-flight paperwork."

    With respect to N1 settings the AAIB reported:

    Passing the upwind end of the runway the aircraft’s ACARS sent a takeoff report, which confirmed that the engines were at an N1 of approximately 81.5%. Other ACARS messages confirmed that the correct weights for the aircraft had been entered into the FMC.

    The aircraft’s auto-throttle BITE8 history showed two messages generated during the climbout. Both messages were consistent with the crew having manually advanced each throttle to a power setting above an N1 of 81.5% when the aircraft was approximately 800 ft aal.

    The Electronic Flight Bags (EFB) used by the crew to calculate the performance figures for entry into the FMC were provided to the AAIB. Initial examination of these devices indicated that the correct figures were calculated by the EFB performance software prior to the aircraft’s departure.

    The AAIB conducted simulator tests to find out whether the aircraft would be able to climb out or stop in case of an engine failure and how such a performance of N1=81.5% could occur in the FMS. The AAIB wrote:

    The AAIB and operator carried out independent assessments of how the incorrect thrust setting might have been programmed into the FMC. Both assessments concluded that the only credible way to achieve a grossly low N1 setting was to enter an extremely low value into the outside air temperature (OAT) field on the n1 limit page. It was found that the takeoff N1 setting used on the flight (81.5%) would be calculated by the FMC if:

    a. The expected top-of-climb outside air temperature (OAT) was entered into the OAT field on the n1 limit page instead of the OAT at the airport (a figure of - 52°C as opposed to +16°C);

    and b. The correct assumed temperature9 of 48°C was entered into the FMC. No other combination of data entries was found which would achieve the same result.

    During the simulation carried out by the AAIB, the aircraft’s performance was assessed following an engine failure immediately prior to V1, with the pilot making a decision by V1 to either abandon or continue the takeoff. In the simulator, the aircraft was able to stop in the runway remaining following a decision to abandon the takeoff, but was unable to climb away safely following a decision to continue the takeoff.

    The AAIB analysed:

    The aircraft took off from Runway 07 with a thrust setting significantly below that required to achieve the correct takeoff performance, and struck a Runway 25 approach light shortly after lifting off.

    The N1 required to achieve the required takeoff performance was 93.3% but 81.5% was used instead. Independent assessments by the AAIB and operator showed that the only credible way for this to have happened was for an error to have been made whilst entering the OAT into the FMC. If the top-of-climb OAT was mistakenly inserted into the OAT field on the n1 limit page (a figure of -52°C as opposed to +16°C), and the correct assumed temperature of 48°C was entered, the FMC would have calculated a target takeoff N1 of 81.5%. The investigation will consider how such a data entry error could have been made, and whether actual aircraft performance matched that which would be expected given the N1 power setting used.

    --- 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 ---

  • #2
    So, the shortened version is "The crew fucked up! " ??
    If it 'ain't broken........ Don't try to mend it !

    Comment


    • #3
      Originally posted by AvHerald
      If the top-of-climb OAT was mistakenly inserted into the OAT field on the n1 limit page (a figure of -52°C as opposed to +16°C), and the correct assumed temperature of 48°C was entered, the FMC would have calculated a target takeoff N1 of 81.5%.
      I agree with you on the TOPMS but this seems like another case where possibly a small software tweak could have a benefit.

      On a modern airliner it seems like the FMC would, or should have, access to the actual outside air temperature via sensors on the aircraft. It's understandable that the sensors might read a little differently from the value the pilots use for planning, since the latter presumably comes from a sensor located elsewhere at the airport. But -52C vs. +16C isn't a "little" difference... surely the computer could compare the OAT it's getting from its sensors and what's entered, and put up a warning message if there's a major discrepancy.
      Be alert! America needs more lerts.

      Eric Law

      Comment


      • #4
        7313 separate "automated" systems that don't seem to talk to each other. makes a wonderful day for thefallible humans trying to manage in the event of a muck-up. hey, which system is doing what now and why?

        Comment


        • #5
          Originally posted by elaw View Post
          I agree with you on the TOPMS but this seems like another case where possibly a small software tweak could have a benefit.

          On a modern airliner it seems like the FMC would, or should have, access to the actual outside air temperature via sensors on the aircraft. It's understandable that the sensors might read a little differently from the value the pilots use for planning, since the latter presumably comes from a sensor located elsewhere at the airport. But -52C vs. +16C isn't a "little" difference... surely the computer could compare the OAT it's getting from its sensors and what's entered, and put up a warning message if there's a major discrepancy.
          Obviously, this is an easy software fix. If an OAT (or any other parameter) is entered that is well out-of-range, the system should be able to recognize this and prompt the crew to check and verify that.

          Websites with customer data fields do this everyday. It's not cutting edge.

          But first, we have to overcome that reluctance in the industry to admit that pilots will make such mistakes and to acknowledge the severity of the threat of these human factors.

          Comment


          • #6
            Originally posted by brianw999 View Post
            So, the shortened version is "The crew fucked up! " ??
            That would be the shortened answer to 90% of aviation incidents, non fatal and fatal accidents.
            If we were happy with that kind of answers we would not have TCAS, GPWS, take off configuration warning, stall warning, overspeed wrning.......
            If we were happy with that kind of answers we would have the accident rate we had in the 70's when we were happy with that kind of answers.

            --- 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


            • #7
              Apologies for the hijack- albeit an on-topic hijack.

              Back in 1982, this horrific crash (pictured below) happened.

              Click image for larger version

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              Indeed, TOPMS would theoretically & likely prevented it.

              However, another concluding comment that came from this crash was- Weak CRM including a BURNING QUESTION OF WHY IN THE HELL DIDN'T THEY JUST FIREWALL THE 'THROTTLES'?

              35 years later, all of these improvements in CRM and procedures, and almost every time Gabriel posts a we-outsiders-say-we-need-TOPMS thread, you can also ask the same BURNING QUESTION OF WHY IN THE HELL DIDN'T THEY JUST FIREWALL THE 'THROTTLES'?.

              I suppose our inability to fix that will embolden Gabriel's argument for TOPMS- but I want to ask, "Why is it that we seem to forget the broadly applicable fundamental of 'just firewall the throttles?" (and yeah, I continue blame Evan for saying that's a type-specific thing).

              I guess I'm still on-board that some sort of BBATL-genuine-required-speed-distance quick-check may be called for/required, and recognize the potential for a smartphone app.

              For the smartphone app, I still need to know a good procedure to notify the cockpit if speed is off (or flaps are not set)...there was that guy who proposed a hotline from the passenger seats a while back...
              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

              Comment


              • #8
                Originally posted by 3WE View Post
                However, another concluding comment that came from this crash was- Weak CRM including a BURNING QUESTION OF WHY IN THE HELL DIDN'T THEY JUST FIREWALL THE 'THROTTLES'?
                They did, apparently, advance the throttles manually ONCE THEY RECOGNIZED THE SITUATION. But by then... eh... it's gonna cost you a tire.

                TOPMS is about helping pilots to RECOGNIZE THE SITUATION while still safely in the low-speed regime, when there is still ample time to FIREWALL THE THROTTLES or stop and try again.

                Comment


                • #9
                  Originally posted by Evan
                  ONCE THEY RECOGNIZED THE SITUATION. But by then... eh... it's gonna cost you a tire.
                  Noted, BUT, there's all those special colored lights and markings that kick in thousands (plural) of feet before the end of the runway. I don't think I'm too out of line for asking why CRM and big-coal-get-me-outa-here levers aren't doing a little bit better job.
                  Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                  Comment


                  • #10
                    Originally posted by 3WE View Post
                    Apologies for the hijack- albeit an on-topic hijack.

                    Back in 1982, this horrific crash (pictured below) happened.

                    [ATTACH=CONFIG]9245[/ATTACH]

                    Indeed, TOPMS would theoretically & likely prevented it.

                    However, another concluding comment that came from this crash was- Weak CRM including a BURNING QUESTION OF WHY IN THE HELL DIDN'T THEY JUST FIREWALL THE 'THROTTLES'?
                    Here, here!!! This is the same that I've always thought and said. And it is documented in the epic "stall" thread (because this was also a stall accident that could have been avoided or recovered with timely application of sound stall recovery procedure).

                    This plane was able to fly. Proof? It did fly. They "just" had to firewall the throttles as soon as the sticksahker started, and manage the AoA.

                    --- 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


                    • #11
                      Originally posted by Gabriel View Post
                      Here, here!!! This is the same that I've always thought and said. And it is documented in the epic "stall" thread (because this was also a stall accident that could have been avoided or recovered with timely application of sound stall recovery procedure).

                      This plane was able to fly. Proof? It did fly. They "just" had to firewall the throttles as soon as the sticksahker started, and manage the AoA.
                      The frightening bit is, I'm not a pilot, but even I know that !
                      If it 'ain't broken........ Don't try to mend it !

                      Comment


                      • #12
                        Originally posted by Gabriel View Post
                        Here, Here!!! [and Brian's comment].
                        Of course we have to remember tunnel vision and confirmation bias that we are probably just as guilty of as humans...but still, I thought that the Air Florida crash might have cemented a broadly-applicable, fundamental procedure to physically move the power levels ALL THE WAY UP if things start looking tight for almost all future operations. (But I guess it would only work for a 737-200)
                        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                        Comment


                        • #13
                          Originally posted by 3WE View Post
                          (But I guess it would only work for a 737-200)
                          But then autothrust derate wouldn't be a concern on the 737-200... unless we're talking about the 737-200(adv)...

                          Comment


                          • #14
                            Originally posted by Evan View Post
                            But then autothrust derate wouldn't be a concern on the 737-200... unless we're talking about the 737-200(adv)...
                            Meh...I get the automatic power setting deal, but I'm hoping you scientific engineers did not remove an override-I-need-full-power(see footnote)-in-30-seconds-Scotty-or-we're-all-dead. An extra notch beyond "HAL-Chosen-takeoff-power".

                            Footnote: "Full power is intended to mean full available power without damaging something. I know you guys locked pilots out from doing that some time ago.
                            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                            Comment


                            • #15
                              Originally posted by 3WE View Post
                              Meh...I get the automatic power setting deal, but I'm hoping you scientific engineers did not remove an override-I-need-full-power(see footnote)-in-30-seconds-Scotty-or-we're-all-dead. An extra notch beyond "HAL-Chosen-takeoff-power".

                              Footnote: "Full power is intended to mean full available power without damaging something. I know you guys locked pilots out from doing that some time ago.
                              Again, it's not an issue of ACCESS to full available power, it's an issue of awareness when there is still time to avoid bending anything yet the situation is not yet obvious to the human pilot. You might notice that thrust levers have not yet been removed from the cockpit and they are designed with the hand in mind. The only thing preventing the pilot from using them is a lack of awareness.

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