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amit24075844

PMDG 737 not stable on touchdown

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Hello,

I have a problem, every time I land with the 737 family aircraft n touchdown the aircraft is not stable and I am leveled on touchdown and I dont know how to fix it.

You can see it on one of my videos.

https://www.twitch.tv/amit240/v/75208532  at 05:10:00 (Time in the video)

thanks for the helpers.

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What hardware controls are you using? Looks possibly like differential breaking is your issue, so if you using toe pedals you might want to use FSPUIC to change the curve and sensitivity of them.

 

Equally there was a cross wind with the landing, and unfortunately FSX (maybe P3D) doesn't do ground effect very well - so cross winds on the ground have a somewhat unrealistic effect on the aircraft at speed - however some nose down and opposite Aileron should help with the control.

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You'll get better rudder travel and steering at touchdown if the yaw damper is off.

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Yaw damper always stays on except for a few non-normal procedures.  Not as realistic, but I have autorudder set on.  In the real aircraft, we rarely touch the rudders in flight.  Rudders are used during takeoff roll, landing roll out, and extensively during engine out conditions.

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Yaw damper always stays on except for a few non-normal procedures.  Not as realistic, but I have autorudder set on.  In the real aircraft, we rarely touch the rudders in flight.  Rudders are used during takeoff roll, landing roll out, and extensively during engine out conditions.

Full names in the forum please.

 

Looks like a hardware issue to me.

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In case you also use Accu-Feel, the "Side forces" setting is horribly exaggerated at the default setting, and leads to all aircraft landing on only one of the main gear, unless the setting is reduced.

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Yaw damper always stays on except for a few non-normal procedures.  Not as realistic, but I have autorudder set on.  In the real aircraft, we rarely touch the rudders in flight.  Rudders are used during takeoff roll, landing roll out, and extensively during engine out conditions.

 

I dont mean to steal this thread for another topic but i always wandered how are crab approaches done? isn't the rudder used extensively in that situation?

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I dont mean to steal this thread for another topic but i always wandered how are crab approaches done? isn't the rudder used extensively in that situation?

 

For a small plane? Yes, but that's a slipped approach (often incorrectly referred to a crabbed approach).

 

For an airliner? No. Fly the approach crabbed (not slipped, like a small plane). Just before touching down, you turn the plane about the yaw axis to align it with the runway by using just enough rudder to do so.

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Fly the approach crabbed (not slipped, like a small plane). Just before touching down, you turn the plane about the yaw axis to align it with the runway by using just enough rudder to do so.

But that's exactly what i am referring to, don't you make use of the rudder to do both things you mention? rudder for maintaining a crabbed (not slipped) approach and again rudder for final alignment....?

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don't you make use of the rudder to do both things you mention?

 

Yes.

 

 

 


rudder for maintaining a crabbed (not slipped) approach and again rudder for final alignment....?

 

No.

 

For a crabbed approach, you simply turn the aircraft into the wind as if you were turning the aircraft to any heading. Then you use the rudder right at the end to align yourself just above the runway.

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The crab doesn't really use rudder until alignment at touchdown. You are turning into the wind and letting the plane fly the way it naturally wants to in order to stay aligned. Thus the crab.

 

In smaller planes we are typically taught to dip a wing and then apply opposite rudder to align the plane on short final. That makes heavy use of rudder and helps not to side load so badly on touchdown.

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The crab doesn't really use rudder until alignment at touchdown. You are turning into the wind and letting the plane fly the way it naturally wants to in order to stay aligned. 

 

ok, sorry guys i am confused now, how do you just "turn the plane in to the wind"? what i am talking about here is a manual landing (no autopilot) with crosswind, i know i have to keep that runway between my legs but the wind pushes we off alignment so i need to put the nose to wind to counteract but if you don't use the rudder what do you use?  did you imply the rudder trim knob as opposed to the pedals? or did you just imply to use the yoke but that would lower my wing making it a slipped approach and that's a no no on a 737 apparently.....sorry i am a biologist trying to have some more fun :)

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ok, sorry guys i am confused now, how do you just "turn the plane in to the wind"?

 

You're overthinking this.

 

You turn the plane like you turn the plane to change to any heading. Except, in this case, you're turning the plane to accommodate wind drift. You simply select a heading that faces into the wind enough that the wind isn't blowing you off of the centerline. The plane is doing this the whole time you're on LNAV. Watch it. Your track will not match your heading unless it's a direct head or tailwind. No rudder is used to do this.

 

 

 


what i am talking about here is a manual landing (no autopilot) with crosswind, i know i have to keep that runway between my legs but the wind pushes we off alignment so i need to put the nose to wind to counteract but if you don't use the rudder what do you use?

 

You use your heading. See above.

 

 

 


did you imply the rudder trim knob as opposed to the pedals?

 

No. Do not use the rudder.

 

 

 


or did you just imply to use the yoke but that would lower my wing making it a slipped approach and that's a no no on a 737 apparently

 

You use the yoke to turn to the heading, but then you level the wings once you're on the new heading (and do not use rudder). You only use the rudder to kick the tail into alignment at the last moment before touchdown. If you google crabbed approach versus slipped approach, you're bound to find all kinds of video and pictures describing it.

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rudder for maintaining a crabbed (not slipped) approach and again rudder for final alignment....?

 

No.

 

For a crabbed approach, you simply turn the aircraft into the wind as if you were turning the aircraft to any heading. Then you use the rudder right at the end to align yourself just above the runway.

 

De-crab during Flare

 

The objective is to maintain wings level during approach, flare and touchdown.

During the approach a crab angle is established with wings level in order to maintain the desired track. During the flare downwind rudder is applied to eliminate the crab and align the aircraft with the centre-line. At the same time apply upwind aileron in order to maintain wings level. These cross controls are maintained throughout the landing phase and the aileron during the landing roll.

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It might sound daft...but are you sure you haven't just got the auto rudder left on in the flight sim settings....both p3d and fsx have it. I have found by mistake that leaving this on can make it very hard to land?

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Ok, i think i got it now. Thank you all. 

No i don't have autorudder set to ON. I actually never really had too much of a problem landing with crosswind, I only wanted to know how are you supposed to do it. 

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Ok, i think i got it now. Thank you all. 

No i don't have autorudder set to ON. I actually never really had too much of a problem landing with crosswind, I only wanted to know how are you supposed to do it. 

 

Ok cool...I couldn't get your video to work btw..

 

I would like to know more about this as well.

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