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Thread: Bad take-off computation.

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    Default Bad take-off computation.

    Hey, I don't work there anymore! http://avherald.com/h?article=4accc5bc&opt=0

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    Senior Member Gabriel's Avatar
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    Of course you don't. This would have never happened with you working there.

    --- 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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    In the AvHerald comments, someone jived that an iPhone app could easily be developed...

    It should also be stated that almost all prior 'tight runway' takeoffs by the crew were likely successful.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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    begs the question: why aren't airports equipped with scales? trucks can be weighed so why not aircraft, especially cargo monsters, or maybe i should say especially large pax aircraft. are airlines simply using a rough guesstimate or average weight for us self-loading cargo? is the weight of all checked luggage actually input into the system?

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    Senior Member 3WE's Avatar
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    Quote Originally Posted by TeeVee View Post
    begs the question: why aren't airports equipped with scales? trucks can be weighed so why not aircraft, especially cargo monsters, or maybe i should say especially large pax aircraft. are airlines simply using a rough guesstimate or average weight for us self-loading cargo? is the weight of all checked luggage actually input into the system?
    Let me breifly hijack the thread...there's all that talk that the lb/passenger estimates are 'off'. Certainly, this would rate a government-funded study? All sorts of refinements seem possible...winter, summer, hoooowaii, hooterville, bizness, pleasure...

    Of course the cargo bunch doesn't need a big scale...they have little scales and adding machines.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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    Senior Member Evan's Avatar
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    Let's look at three EXISTING technologies to combat human error:

    TOPMS - (Take-Off Performance Monitoring System) This should be already installed on every commercial transport aircraft with a digital FMS. It should include GPS and a database for every runway length and receive automated NOTAM updates. What's the downside? A bit of cost involved: but it should be achievable without new hardware. The potential for failure: that hasn't stopped us from making GPWS or TCAS standard. There MAY be a possibility of a false warning on rare occasions: big deal, you stop, you try again (maybe with it disabled, but this time you have REALLY gone over your numbers and are VERY aware of the takeoff performance situation). It could cause high-speed reject accidents: The system would be able to detect a problem before reaching the high-speed regime and would be inhibited above the low-speed regime. We dont NEED it: the evidence keeps showing us that we do need it.

    OBWBS: (On-Board Weight-On-Wheels System) This dates back to the classic 747's and was offered as an option. The plane weighs itself using sensors in the gear struts. It proved unreliable due to a number of external factors including wind effects and was too maintenance-dependent. Pilots often did the calculations themselves to be certain.

    REDUNDANCY: This one seems to work the best. One pilot does the weight and balance calculations, the other checks those calculations. One pilots enters the data in the FMS, the other checks that too. One pilot flies the plane down the runway, paying attention to indicated and perceived performance, the other monitors indicated and perceived performance.

    Add TOPMS to REDUNDANCY and this will probably never happen again.

    Rely on training and pilot competency alone and it will continue to happen.

    That seems to be the choice we have.

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    Quote Originally Posted by Gabriel View Post
    Of course you don't. This would have never happened with you working there.

    Wouldn't have happened with me as Pilot in Command I can tell you that!

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    Quote Originally Posted by Evan View Post
    Let's look at three EXISTING technologies to combat human error:

    TOPMS - (Take-Off Performance Monitoring System) This should be already installed on every commercial transport aircraft with a digital FMS. It should include GPS and a database for every runway length and receive automated NOTAM updates. What's the downside? A bit of cost involved: but it should be achievable without new hardware. The potential for failure: that hasn't stopped us from making GPWS or TCAS standard. There MAY be a possibility of a false warning on rare occasions: big deal, you stop, you try again (maybe with it disabled, but this time you have REALLY gone over your numbers and are VERY aware of the takeoff performance situation). It could cause high-speed reject accidents: The system would be able to detect a problem before reaching the high-speed regime and would be inhibited above the low-speed regime. We dont NEED it: the evidence keeps showing us that we do need it.

    Even if there was such a thing, it would not have helped them here.

    OBWBS: (On-Board Weight-On-Wheels System) This dates back to the classic 747's and was offered as an option. The plane weighs itself using sensors in the gear struts. It proved unreliable due to a number of external factors including wind effects and was too maintenance-dependent. Pilots often did the calculations themselves to be certain.

    This one we got!

    REDUNDANCY: This one seems to work the best. One pilot does the weight and balance calculations, the other checks those calculations. One pilots enters the data in the FMS, the other checks that too. One pilot flies the plane down the runway, paying attention to indicated and perceived performance, the other monitors indicated and perceived performance.

    This, and a time crunch up against curfew, with a last minute runway change is what bit them. And like I said above, If I had been the PIC, it would not have happened. And now I will explain why. This is the perfect example of breakdown of CRM and the beginning of the error chain. Last minute runway change, Okay everyone we just had a runway change, I want everyone of us to go over the take-off data and agree. Up against curfew, not my problem that the schedulers, loaders etc, F'd up. Send the crew back to the hotel, get another crew or call us in 8 hours AFTER I close my room door.

    Add TOPMS to REDUNDANCY and this will probably never happen again.

    Rely on training and pilot competency alone and it will continue to happen.

    That seems to be the choice we have.
    See my above comments.

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    Senior Member Gabriel's Avatar
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    BB, you obviously have more information that we. Can you please explain the sequence of events that led to this incident? I understand that there was a runway change, but what was the mistake after that? They didn't do anything to review the TO performance? Or they did something but incomplete? Or they did it but made mistakes?

    Additionally, in the advanced version of the TOPMS, you enter the RWY and intersection that you are going to use as well as the TO parameters in the FMS. If either the acceleration is incorrect (doesn't match what was expected for the TOW entered and the TO power setting calculated) OR if the RWY or intersection is incorrect (the GPS would be part of that, and compare your position with the RWY entered, as well as the TO start point), you would get the alarm quite early in the TO roll.

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    Senior Member Gabriel's Avatar
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    Quote Originally Posted by BoeingBobby View Post
    Wouldn't have happened with me as Pilot in Command I can tell you that!
    Ahw, not as good as ITS. It would not have happened with him even as FO.

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
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    Quote Originally Posted by BoeingBobby View Post
    This one we got!
    Was it reliable?

    Quote Originally Posted by BoeingBobby View Post
    This, and a time crunch up against curfew, with a last minute runway change is what bit them. And like I said above, If I had been the PIC, it would not have happened. And now I will explain why. This is the perfect example of breakdown of CRM and the beginning of the error chain. Last minute runway change, Okay everyone we just had a runway change, I want everyone of us to go over the take-off data and agree. Up against curfew, not my problem that the schedulers, loaders etc, F'd up. Send the crew back to the hotel, get another crew or call us in 8 hours AFTER I close my room door.
    Aha, realities enter in. Still I have to disagree with you that TOPMS wouldn't have made a difference in a situation like that. If the decision is between revisiting the data and risking running up against curfew or winging it, wouldn't it be helpful to have a system that can re-crunch the data in .0000001 second and warn you early on the roll if your last-minute-change-no-time-to-think thinking wasn't quite right?

    Quote Originally Posted by Gabriel View Post
    Ahw, not as good as ITS. It would not have happened with him even as FO.
    Well, ITS would always have his head out the window feeling how fast his cigar burned, and this would tell him everything... (on the 747, he would have to stick his head out the roof hatch, tank commander style, and yell orders down to his F/O at the controls).

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    Quote Originally Posted by Gabriel View Post
    BB, you obviously have more information that we. Can you please explain the sequence of events that led to this incident? I understand that there was a runway change, but what was the mistake after that? They didn't do anything to review the TO performance? Or they did something but incomplete? Or they did it but made mistakes?


    You are right, I still have connections there, and because there were conflicting posts on both PPrune and APC, I called a friend that is a check airman there. They have all been briefed on the incident.

    And I agree with you both that ITS would not have done this either. He has been a freight dog long enough to know the things that will bite you.

    So, we have a crew, (10-year Captain and a new First Officer, I have not been told of a third pilot) Late at night out of Narita up against the airport curfew. The pilot flying got the ATIS off of ACARS and entered the data into the FMS along with the data from the OFP (official flight plan) and the weight and balance (that is done by ground crew Evan). The ACARS now spits out take-off performance data. This is now entered into the FMS again by the pilot flying, and now verified by the pilot monitoring. Check lists complete, call for push-back. Start engines, wave off the ground crew and another check list. Hello ground Polar 213 heavy ready to taxi stand 208. A thick Japanese accent reads back, Polar 213 please be advised of runway change, now departing runway 34 right, clear taxi runway 34 right, whiskey 5, whiskey, whiskey 10, Charlie, bravo 10 for 34 right read back. It is a long and not east to follow taxi! Pilot flying tells the pilot monitoring, I will taxi the aircraft, you change the runway and the take-off data. Well when you do that you get a big fat TAKE-OFF SPEEDS DELETED, in the CDU. So now the pilot monitoring re-inputs the new V speeds. Problem is, that they had a de-rated power setting of TO2 in the FMS from the 13123’ runway they had originally planned on taking-off from, and now they are taking off from an 8202’ one. The V speeds were right for the shorter runway, but they missed that the de-rate had been removed in the new data, and was now calling for a setting of TO (full thrust). THE PILOT FLYING DID NOT VERIFY THE NEW INFORMATION! They departed the pavement with 85 meters (279’) to spare. Took down piece of a fence and did some supposed damage to some farmers property with the jet blast. So now, knowing Atlas the way I do, all of the pilots will get to take some kind of online test about it. And that will make the FAA happy.

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    Quote Originally Posted by BoeingBobby View Post
    You are right, I still have connections there, and because there were conflicting posts on both PPrune and APC, I called a friend that is a check airman there. They have all been briefed on the incident.

    And I agree with you both that ITS would not have done this either. He has been a freight dog long enough to know the things that will bite you.

    So, we have a crew, (10-year Captain and a new First Officer, I have not been told of a third pilot) Late at night out of Narita up against the airport curfew. The pilot flying got the ATIS off of ACARS and entered the data into the FMS along with the data from the OFP (official flight plan) and the weight and balance (that is done by ground crew Evan). The ACARS now spits out take-off performance data. This is now entered into the FMS again by the pilot flying, and now verified by the pilot monitoring. Check lists complete, call for push-back. Start engines, wave off the ground crew and another check list. Hello ground Polar 213 heavy ready to taxi stand 208. A thick Japanese accent reads back, Polar 213 please be advised of runway change, now departing runway 34 right, clear taxi runway 34 right, whiskey 5, whiskey, whiskey 10, Charlie, bravo 10 for 34 right read back. It is a long and not east to follow taxi! Pilot flying tells the pilot monitoring, I will taxi the aircraft, you change the runway and the take-off data. Well when you do that you get a big fat TAKE-OFF SPEEDS DELETED, in the CDU. So now the pilot monitoring re-inputs the new V speeds. Problem is, that they had a de-rated power setting of TO2 in the FMS from the 13123’ runway they had originally planned on taking-off from, and now they are taking off from an 8202’ one. The V speeds were right for the shorter runway, but they missed that the de-rate had been removed in the new data, and was now calling for a setting of TO (full thrust). THE PILOT FLYING DID NOT VERIFY THE NEW INFORMATION! They departed the pavement with 85 meters (279’) to spare. Took down piece of a fence and did some supposed damage to some farmers property with the jet blast. So now, knowing Atlas the way I do, all of the pilots will get to take some kind of online test about it. And that will make the FAA happy.
    I realize you don't work there anymore, but discretion is still a good thing, no?

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    Quote Originally Posted by ATLcrew View Post
    I realize you don't work there anymore, but discretion is still a good thing, no?
    Stopping the rumors, stating the facts. I didn't name any names.

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    Quote Originally Posted by ATLcrew View Post
    I realize you don't work there anymore, but discretion is still a good thing, no?
    pilots' version of the blue wall of silence? you think that helps in the long run? sorry mate, all will come out in the wash anyway. the CAA's release all the details at one point so, the dirt only stays hidden for so long.

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    Quote Originally Posted by BoeingBobby View Post
    You are right, I still have connections there, and because there were conflicting posts on both PPrune and APC, I called a friend that is a check airman there. They have all been briefed on the incident.

    And I agree with you both that ITS would not have done this either. He has been a freight dog long enough to know the things that will bite you.

    So, we have a crew, (10-year Captain and a new First Officer, I have not been told of a third pilot) Late at night out of Narita up against the airport curfew. The pilot flying got the ATIS off of ACARS and entered the data into the FMS along with the data from the OFP (official flight plan) and the weight and balance (that is done by ground crew Evan). The ACARS now spits out take-off performance data. This is now entered into the FMS again by the pilot flying, and now verified by the pilot monitoring. Check lists complete, call for push-back. Start engines, wave off the ground crew and another check list. Hello ground Polar 213 heavy ready to taxi stand 208. A thick Japanese accent reads back, Polar 213 please be advised of runway change, now departing runway 34 right, clear taxi runway 34 right, whiskey 5, whiskey, whiskey 10, Charlie, bravo 10 for 34 right read back. It is a long and not east to follow taxi! Pilot flying tells the pilot monitoring, I will taxi the aircraft, you change the runway and the take-off data. Well when you do that you get a big fat TAKE-OFF SPEEDS DELETED, in the CDU. So now the pilot monitoring re-inputs the new V speeds. Problem is, that they had a de-rated power setting of TO2 in the FMS from the 13123’ runway they had originally planned on taking-off from, and now they are taking off from an 8202’ one. The V speeds were right for the shorter runway, but they missed that the de-rate had been removed in the new data, and was now calling for a setting of TO (full thrust). THE PILOT FLYING DID NOT VERIFY THE NEW INFORMATION! They departed the pavement with 85 meters (279’) to spare. Took down piece of a fence and did some supposed damage to some farmers property with the jet blast. So now, knowing Atlas the way I do, all of the pilots will get to take some kind of online test about it. And that will make the FAA happy.
    In your experience, how many times in 100 would the verification step catch an error?

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    Senior Member Gabriel's Avatar
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    Thank you BB for the detailed explanation.

    --- 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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    Quote Originally Posted by TeeVee View Post
    pilots' version of the blue wall of silence?
    No, more like common decency and courtesy. There are people whose job it is to release the wash, and BB is not one of them.

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    Quote Originally Posted by ATLcrew View Post
    No, more like common decency and courtesy. There are people whose job it is to release the wash, and BB is not one of them.

    Like I said, just the facts Mam, just the facts, no names.

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    Senior Member TeeVee's Avatar
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    Quote Originally Posted by ATLcrew View Post
    No, more like common decency and courtesy. There are people whose job it is to release the wash, and BB is not one of them.
    like i suspected, blue wall stuff. you do realize that this helps no one? and further, the names were omitted to "protect" the not so innocent. and of course, i'm being sarcastic here, as it's not about innocence or guilt. this was very very likely pilots' error. as an alleged pilot yourself, you should be grateful for the lesson learned.

    i'm not advocating anyone getting canned over this, since i'm not in the position to judge whether this was the kind of mistake that absolutely should never have been made. and i rarely, if ever, rejoice in anyone losing their job. but you've gotta think of it this way: being in charge of an enormously dangerous instrumentality carries with it an enormous burden not to eff up, and if you do, you're gone.

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