Hi all,

I'd like some advice on take off technique. I posted this in the PMDG forum too, but knowing the wealth of knowledge here, I thought I'd post here too.

When I'm rolling down the runway, I add in rudder to counteract any crosswind to keep the aircraft straight down the runway (it appears very rarely that I don't have ANY crosswind during TO).

However, when I rotate, this rudder adds in some weird oscillation and as I remove it, the nose yaws massively.

Should I be using a combination of runnder and/or aileron here? So as the aircraft picks up speed on the runway, I transition from the rudder (which at lower speeds is also controlling the nose wheel) to aileron to combat the cross wind?

If I don't add any rudder, the aircraft veers to one side of the runway.

Looking forward to all your advice!

Thanks!

51 minutes ago, BWBriscoe said:

I'd like some advice on take off technique.

Here's how to do it in the sim with the 777:

 

And here is the same concept shown by a CFI in a GA aircraft to show and discuss the technique in a bit more detail:

During take off roll keep ailerons  to the wind and use rudders to keep directional control . As you build up the speed, ease up aileron deflection (because they  become more responsive )

Notice, after you lift off the nose will immediately point at direction where wind is coming . From that point you compensate drift by offsetting your heading 

7 hours ago, sd_flyer said:

During take off roll keep ailerons  to the wind and use rudders to keep directional control . As you build up the speed, ease up aileron deflection (because they  become more responsive )

Notice, after you lift off the nose will immediately point at direction where wind is coming . From that point you compensate drift by offsetting your heading 

Bang on perfect.  Any airplane will yaw into the wind after takeoff.  Flown small GA planes for over 600 hours and sometimes in real heavy wind you are basically pointing 50 degrees or so off the runway because of the wind.  It’s pretty wild.  No idea how a 777 would react but my sense is it would not be anywhere near as severe as a small GA plane.

I pointed out in another thread that I’ve watched streams where a real world airline pilot said that MSFS handles low level wind very poorly and aerodynamically backwards.  That might be contributing to your issue.

4 hours ago, jspilot said:

Bang on perfect.  Any airplane will yaw into the wind after takeoff.  Flown small GA planes for over 600 hours and sometimes in real heavy wind you are basically pointing 50 degrees or so off the runway because of the wind.  It’s pretty wild.  No idea how a 777 would react but my sense is it would not be anywhere near as severe as a small GA plane.

I pointed out in another thread that I’ve watched streams where a real world airline pilot said that MSFS handles low level wind very poorly and aerodynamically backwards.  That might be contributing to your issue.

I haven't flown airliners but I do friends who do. One of the retired 777 captain. They do struggle too as well LOL

 

 

On the 747 we used to add one notch of into wind aileron from stationary for every 10 kts of Xwind, that technique got amended to just keeping the wings level.

On the 787, which is is designed to be a pretend 777 the technique is just apply enough into wind aileron to keep the wings level, which is easy as you’re using the HUD on takeoff so it’s very accurate. Above 60kts the rudder becomes active and so in theory the FBW will keep you straight without much manual rudder required.

Thats the theory, but I don’t find it does a great job so usually end up dancing on the rudder pedals.

I presume the 777 would be the same but don’t know how well PMDG have implemented the FBW, I own the aircraft but not flown it much yet.

5 hours ago, jon b said:

On the 747 we used to add one notch of into wind aileron from stationary for every 10 kts of Xwind, that technique got amended to just keeping the wings level.

On the 787, which is is designed to be a pretend 777 the technique is just apply enough into wind aileron to keep the wings level, which is easy as you’re using the HUD on takeoff so it’s very accurate. Above 60kts the rudder becomes active and so in theory the FBW will keep you straight without much manual rudder required.

Thats the theory, but I don’t find it does a great job so usually end up dancing on the rudder pedals.

I presume the 777 would be the same but don’t know how well PMDG have implemented the FBW, I own the aircraft but not flown it much yet.

Hi Jon,

 

It's almost the same technique here: initial roll one index L/R based on where the wind is blowing from, and from there, whatever is necessary to keep the wings level. The reason only for one index left or right was to avoid getting too much drag and affect t.o. performance, especially on the ones at max t.o. weights. The PMDG 777 got this quite right. The other aspect of FBW trim speed is that it is quite an awful implementation and needs much attention. I wonder how they managed to break it like that; they ignored the real pilots inputs they have there as technical advisors. 

You can use this entry at

 

[airplane_geometry]

control_rudder_forcebased = 1.0

control_rudder_maxforce_student = 120.0

control_rudder_minforce_student = 8.0;

control_rudder_still_force_at_max = 4.0;

control_rudder_still_force_to_move = 8.0;

control_rudder_dynpres_ratio_force_at_max = 1.90;

control_rudder_dynpres_ratio_force_to_move = 0.6;

control_rudder_neutral_return_force_scalar = 1.0;

 

and you will find a better rudder reaction.

You don’t “pre-add” aileron in jets, you add what you need to keep the wings level. If you’re adding more rudder during the roll, you’ll likely need more aileron, opposite to the direction of the rudder (cross controlled). Keeping the wings level is super important because you could potentially have contact with the runway (wing/flap/pod) and/or drift off of centerline too early after rotation. 
 

Once in the air, gently maintain wings level while simultaneously removing the rudder and aileron to their neutral positions. 

1 hour ago, V1ROTA7E said:

You don’t “pre-add” aileron in jets,

I want to share with you some highlights to consider. We do pre-add ailerons in jets, and it depends on SOPs, high wing, low wing engine pod clearance, specific shapes of winglets, bank angle limitations, etc. In our case, 1 index left/right is the start point when it exceeds 10 KTS X-WIND, and the penalty amount, the performance penalty, is negligible. However, acceleration penalties are more significant in ample aileron and rudder cross controls. As an example, as mentioned above, we also check on the PFD bank angle indication during acceleration and adjust the correct amount of aileron and rudder displacement accordingly. It's the same mentality when we push the yoke/stick during t.o. roll, not full L/R or DOWN as some people do it wrong.

1 hour ago, V1ROTA7E said:

You don’t “pre-add” aileron in jets, you add what you need to keep the wings level. If you’re adding more rudder during the roll, you’ll likely need more aileron, opposite to the direction of the rudder (cross controlled). Keeping the wings level is super important because you could potentially have contact with the runway (wing/flap/pod) and/or drift off of centerline too early after rotation. 
 

Once in the air, gently maintain wings level while simultaneously removing the rudder and aileron to their neutral positions. 

I guess jet to jet is different. When I was training on level D Antonov 124 sim it was requirement . May be it due to narrow main gear base and high wing that makes a difference 

10 hours ago, LRBS said:

We do pre-add ailerons in jets

Maybe you do, but we don’t. This has been the case on every transport category jet I’ve flown. Pre adding aileron is for GA, for airliners add what is needed. 

5 hours ago, V1ROTA7E said:

Maybe you do, but we don’t. This has been the case on every transport category jet I’ve flown. Pre adding aileron is for GA, for airliners add what is needed. 

What we think and what is happening in the airline industry is very interesting, especially regarding different procedures. I wouldn't rule that only "for airliners, add what is needed." Whether we agree or not, each airline has its SOPs, not necessarily only for "airliners." This is just one small technique among the others used by airlines. Without a doubt, it's not worth disputing; it occurs or not, whether we are in agreement or not.

6 hours ago, V1ROTA7E said:

Maybe you do, but we don’t. This has been the case on every transport category jet I’ve flown. Pre adding aileron is for GA, for airliners add what is needed. 

I do understand what you guys do; I am not arguing or looking to get into any unproductive discussion here. This is from the BFCTM, where their recommendation is clear enough, and some airlines and ours added the 10 KTS X-WIND data for further clarification. 

Edited September 4, 20241 yr by LRBS

Yes, pre adding into wind aileron was definitely a Boeing issued procedure when I started flying the 747 back in 1997, the procedure eventually got replaced by just flying the wing, not sure exactly when that happened.

As LRBS says, there is a limit to how much aileron to put in (I think it was somewhere like 2.5 or 3 units on the 74) after that the upwind spoilers start deploying with the ailerons, so is a performance issue.

14 minutes ago, jon b said:

not sure exactly when that happened.

This is the latest BFCTM. It's interesting to see what it would be like in 2024.