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jazz69

Reset trim after landing

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Hello all. Something just came to me while I was flying over Cuba on the way to Jamaica. On some of the in flight videos I have seen I notice that when pilots stop the aircraft at the gate they seem to do something whch, I assume resets the trim to a deffault setting. I say this because the wheel seems to spin franticly before coming to a stop. Is this the case or does it serve some other purpose? Have I just imagined this? And also while I am thinking about it does the NGX do this? I am looking about my pedestal as I type and not even getting a hint of anything relating to this. Not terribly important it was just a thought but if anyone can shine some light on this rather dull thought of mine I would be most interested. Regards

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In one of the videos by skysurfer007 (don't remember his real name, but it's the YouTube name of the real-world 737 pilot who made the Madeira video that was posted here, among other things), I remember him resetting the trim to 5 units after landing -- as he said, the idea is for the trim to be in the range of trim positions required for take off, so that no lengthy retrimming will be needed before the next takeoff. There is also an item in FCOM v1 (SP.16.16) that states stabilizer trim should be set to 0 to 2 units after landing in icing conditions; this "prevents melting snow and ice from running into balance bay areas and prevents the stabilizer limit switch from freezing." This may also be what you have seen. --Martin Boehme

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The checklist I have from an actual airline, states "Stab Trim - Reset", first item on the after landing checklist. Not sure where I am supposed to reset it to, so i set it to 5, seeing as how calculated trim for the next flight is usually a little over or under 5.

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I remember for the Just Flight videos, on the one about South African Airlines 737-800, before start they would cycle the trim through it's entire range, and the do some turns by hand, so they can check it's functioning properly.

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I believe at Westjet this is an after-landing procedure - set the trim to 5 units. "Trim - Reset" is on the After Landing checklist. Sam Kharey

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Another point just occurred to me -- not sure whether this is part of the consideration for resetting trim or not, but if trim is reset to the middle of the takeoff range after landing, then if the crew forget to set the trim on the next takeoff, the consequences will hopefully be benign... --Martin Boehme

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No, Seriously it has nothing to do with the crew forgetting to set trim on T/O, I know it has happened before but ........NO. On the 744 after landing checklist is to set trim back to neutral it is just good airmanship, Some SOP on the 744 and I am sure it will be the same with other types is to set trim to a certain stab settiing so on the next walk around you can check it matches with the markers on the Stab Trim, Airbus Ground law does it for you. I read a really good comment on this forum today, not everything is done the same way in this industry, SOP can vary by a huge amount, don't think too deep outside of the Boeing FCOM

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Just resetting the trim to 5. Trim isn't usually too far off from 5, so you'd probably be able to muscle it into the air if you accidentally forget to set it. You might have noticed that the trim runs faster with flaps down, so that's a good reason to do it on the after-landing flow.

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At American Airlines we just left the trim where it was after landing for the last 12 years. In the last few months we have changed our procedure to set the trim to 4 units after landing, On the leading edge at the root of the left stabilizer there is a black line. When the Stab trim is set to 4 units that line lines up with a black line on the fuselage. There are two other black lines on the fuselage that I believe line up with stab trim full up and full down. We were never given a reason for the change though.

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