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A nasty moment ...

Old 15th Aug 2022, 00:49
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A nasty moment ...

Taken at ADL RW 05 about a week ago - a significant cross wind (left to right) was active. Do the scimitar winglets on the 737 MAX series make things more interesting in this situation?

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Old 16th Aug 2022, 15:12
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Originally Posted by FullOppositeRudder View Post
Taken at ADL RW 05 about a week ago - a significant cross wind (left to right) was active. Do the scimitar winglets on the 737 MAX series make things more interesting in this situation?

https://www.youtube.com/watch?v=pV6JhHnh3D8
Not a current 737 pilot (flew the classics), but I can’t help thinking there might be some Pilot Induced Oscillation (PIO) in there. RH scimitar came pretty close to the ground. Have no idea of conditions at ADL, whether this turbulence is a “usual” occurrence.

Last edited by oceancrosser; 16th Aug 2022 at 15:28.
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Old 19th Aug 2022, 03:45
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Looks like a big rudder deflection at around 0:11 just before the left roll, which then seems to be overcorrected.
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Old 19th Aug 2022, 12:10
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Originally Posted by FullOppositeRudder View Post
Taken at ADL RW 05 about a week ago - a significant cross wind (left to right) was active. Do the scimitar winglets on the 737 MAX series make things more interesting in this situation?

https://www.youtube.com/watch?v=pV6JhHnh3D8


Any landing that... what, you want to reuse the plane? Really?...

lads got close to a pod scrape, a slightly lower attitude and it would be a lot more expensive than mere apologies at the MCD on deplane.

The rudder/yaw/roll lag is in play, so yeah, there is a bit of a driver-machine phase lag thingy going on. This would be an example where the MIL-HDBK-1797A PIO term would be better replaced by aircraft-pilot coupling, the phase ;ag ends up being damped by Mother Earth before it really gets going.


The scimitar winglet reduces wing tip clearance, but those are pretty healthy margins to start with, getting out of sorts to the point that they are "exciting" [ a term that has been used to describe performance along with "sporty"]. Winglets do 1 main thing and 3 other add ons. They act to effectively increase aspect ratio, the rest of the stuff on tip vortices follows that basic point. They do that without increasing substantially the wings root bending moment. If you can design the wing for the higher aspect ratio, you are better with a tip extension over the winglet, but they sure look moddiny. [the B744 performance change for flight without a winglet was 0.0% change...] winglets lower the flutter boundary of a wing generally, and that takes more structure to recover... winglets usually reduce aileron authority slightly, and usually will reduce x-wind limit slightly. Mainly, they look pretty, and if the wing could have taken the tip extension, that would be the better use of tin. They do alter lateral directional stability, but not so much, if you had a dutch roll deal before that will become more interesting usually.
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Old 31st Aug 2022, 00:53
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Belated thanks FDR - your explanation is much appreciated.

FOR
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Old 3rd Sep 2022, 15:42
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Hard to be sure from the angle, but it suggests to me that PF was crabbing in because of the crosswind, then just before the mains touched, they straightened with rudder and put in some into-wind left roll to counter the rudder induced roll - which is standard - but overcooked it and/or PM said "careful !" but PF overreacted and rolled too far right.

Or the crosswind suddenly dropped.

Possibly a novice PF learning crosswind landing technique and not quite getting it correct - we've all been there. A change of underwear and a few more crosswind landings, and they will get the hang of it.
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Old 3rd Sep 2022, 21:34
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The rudder inputs may not be pilot induced, I've seen a video on you tube of a go round I did in Storm Doris and the rudder was going left and right all down the approach after AP disconnect but I didn't move the rudder pedals at all, it was the yaw damper working overtime in conjunction with aileron input.

PS you can tell it was a Windshear go round because the gear and flap stayed where they were.
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