Go Back  PPRuNe Forums > Misc. Forums > Spectators Balcony (Spotters Corner)
Reload this Page >

Crosswind Takeoff 33kts 737NG

Spectators Balcony (Spotters Corner) If you're not a professional pilot but want to discuss issues about the job, this is the best place to loiter. You won't be moved on by 'security' and there'll be plenty of experts to answer any questions.

Crosswind Takeoff 33kts 737NG

Old 25th Feb 2021, 09:35
  #1 (permalink)  
Thread Starter
 
Join Date: Aug 2014
Location: Edinburgh
Age: 33
Posts: 390
Crosswind Takeoff 33kts 737NG

With a XW off 33kts right on the limit how much rudder control does it take to keep the nose pointing down the Centreline? Do you use the Tiller Steering during the initial part of the takeoff run (upto 40kts)

Thanks

Driver 170 is offline  
Old 25th Feb 2021, 13:30
  #2 (permalink)  
 
Join Date: Mar 2001
Location: Either the back of a sim, or wherever Crewing send me.
Posts: 991
You use sufficient rudder to keep the aeroplane tracking down the centreline, it’s almost impossible to quantify how much that is.

There is no need to use the tiller, you might be in the right hand seat which might not have a tiller.
Johnny F@rt Pants is offline  
Old 25th Feb 2021, 14:22
  #3 (permalink)  
 
Join Date: Dec 1999
Location: luton,geneva,tokyo
Posts: 15
And as you rotate, if you release the rudder gently the aircraft weathercocks into wind and you have the drift corrected for the initial flight phase.
Into wind aileron is also required during the ground run in strong xw.
billovitch is offline  
Old 25th Feb 2021, 15:50
  #4 (permalink)  
 
Join Date: Feb 2003
Location: Blue sky
Posts: 112
Rudder is connected to the nose wheel steering so there is no point in using the tiller, it would only be a very uncomfortable ride.

Rudder deflections are more like "kicks" because it is a search for some kind of balance with changing winds. Once beyond 80kts, the aileron (control wheel) should come in which is - unlike the rudder - a constant deflection. You would notice the required rudder pedal "kick amplitude" is reduced as more and more aileron is put in. At a certain control wheel displacement (aileron deflection), the ailerons cancel out almost all of the required rudder pedal deflections. That's when aileron input is correct and you can rotate without wingdrop (which is to be avoided on the B737).
BraceBrace is offline  
Old 25th Feb 2021, 16:14
  #5 (permalink)  
 
Join Date: Mar 2001
Location: Either the back of a sim, or wherever Crewing send me.
Posts: 991
At a certain control wheel displacement (aileron deflection), the ailerons cancel out almost all of the required rudder pedal deflections. That's when aileron input is correct and you can rotate without wingdrop
Am I reading this right BB? Are you saying that as you input aileron into wind you have to reduce the rudder input as the aileron input means the rudder isn’t required?
Johnny F@rt Pants is offline  
Old 25th Feb 2021, 18:43
  #6 (permalink)  
 
Join Date: Feb 2003
Location: Blue sky
Posts: 112
The rudder is the tool to track centerline, the ailerons the tool to keep wings level during rotation.

The ultimate end goal is to make a rotation absolutely wings level. For this you need correct aileron input from the start of the rotation, with nose gear still on the ground. How much? After 80kts, slowly increase control wheel deflection untill rudder deflection "amplitude" is minimal. You will still be "kicking the rudder" to track your centerline, but the kicking will be very very minimal.

If you fly the B737 just try it. Correct aileron reduces required rudder for centerline tracking.
BraceBrace is offline  
Old 26th Feb 2021, 06:29
  #7 (permalink)  
 
Join Date: Dec 1999
Location: luton,geneva,tokyo
Posts: 15
But the rudder is applied out of wind.
This prevents the weathercock effect.
The aileron is applied into wind.
This keeps the aircraft weight evenly distributed and prevents wing lift.

Wind from left - rudder right - ailerons left.
Thatís on the ground.

Once in the air rudder should be zero - if you release gently just as you rotate, the weathercock is allowed to occur - which effectively compensates for drift.
The aileron input should be taken out at this time too. During the weathercocking there will be a roll couple and releasing the aileron input compenstates this to some extent.



billovitch is offline  
Old 26th Feb 2021, 08:20
  #8 (permalink)  
Thread Starter
 
Join Date: Aug 2014
Location: Edinburgh
Age: 33
Posts: 390
This is all interesting for a enthusiast. I have been reading the FCTM from Boeing but its great to hear mixed operational experiences from line pilots.

Now the tricky part using the rudder is for De-Crab during flare at approximately 20ft as you retard the Thrust levers and hold that pitch. Must take some considerable practice. I know most airlines don’t allow new Cadets with certain wind factor and hours on type to do any crosswind landing or takeoff
Driver 170 is offline  
Old 18th Mar 2021, 01:52
  #9 (permalink)  
 
Join Date: Nov 2005
Location: River Thames & Surrey
Age: 72
Posts: 9,001
When I was working at Sumburgh back in 1972, I returned from lunch to find a piece of paper on the controllers desk with '160/18' written on it.
I was told that it was the wind direction/speed which I had to pass to the pilot of the BEA Viscount which was due to depart shortly.
No I don't remember what the wind actually was but it wasn't 160/18!!
chevvron is offline  
Old 18th Mar 2021, 07:25
  #10 (permalink)  
 
Join Date: Mar 2001
Location: Either the back of a sim, or wherever Crewing send me.
Posts: 991
Now the tricky part using the rudder is for De-Crab during flare at approximately 20ft as you retard the Thrust levers and hold that pitch. Must take some considerable practice. I know most airlines don’t allow new Cadets with certain wind factor and hours on type to do any crosswind landing or takeoff
It’s not tricky at all really, but it does take some practice. You flare as normal at circa 20’ still crabbed, then retard the thrust levers then as you are about to “impact” the runway you squeeze the appropriate rudder pedal to align the aeroplane with the rudder, you must also apply the opposite aileron to prevent the roll effect of the rudder input.
Johnny F@rt Pants is offline  
Old 18th Mar 2021, 07:33
  #11 (permalink)  
 
Join Date: Mar 2001
Location: Either the back of a sim, or wherever Crewing send me.
Posts: 991
When I was working at Sumburgh back in 1972, I returned from lunch to find a piece of paper on the controllers desk with '160/18' written on it.
I was told that it was the wind direction/speed which I had to pass to the pilot of the BEA Viscount which was due to depart shortly.
No I don't remember what the wind actually was but it wasn't 160/18!!
I vividly remember my first landing in Sumburg, it was dark so we couldn’t use runway 15, 09 it was then, with a lovely wind of 160/33 gusting more than double that!! It were a bit rough!!
Johnny F@rt Pants is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.