Steering on final with rudder

[dutchroll]

I do not get it either and think it is a bad idea, I imagine if you did it in a passenger jet you would make your passengers airsick.

It's very possible that it will de-stabilise your approach in many jets regardless of how many engines are working. Things with big wings just don't like it.

Start peddling the rudder on final approach during a sim check with an airline and you won't like the checker's response.

 

Even with an engine out, you set or trim the rudder position for balanced flight and leave it there. Peddle it to the point of being unbalanced in a B767 with an engine out and the autopilot engaged, and you'll roll it upside down.

 

Try to pick up a wing with a coarse rudder input during a STOL landing with 40 flap in a Caribou and you'll become a statistic.

 

These things are why we were taught as fresh faced 18 year olds to only ever use the rudder in flight to balance/coordinate a turn, and to do that properly. Specific exceptions generally involved prevention of yaw in various cases such as stalling or engine failure, and crosswind landing if you're using the sideslip technique.

 

 

[facthunter]

You give the rudder as much as it needs to maintain heading at the extreme situation . V1 VMC g to VMCa and the designer doesn't usually give you much surplus. It's usually about all there is available. As airspeed increases it becomes more effective and you can use a bit less rudder input. If you press the wrong pedal the plane will do a barrel roll (or part of. The last part would be under the ground). All done with great care..There are no wild oscillations permitted. Nev

 

 

[Contact Flying]

Garfly,

 

Yes, in my country the Dutch Roll was taught as a coordination maneuver. I didn't worry about the video because he explained what he was doing well (side slip) regardless of what he called it. As Nev says the big iron boys have their own language.

 

Nev,

 

Does your Aviation Agency require a Type Certificate for big (12,500 US pounds) airplanes? I think the new little airplanes with weird control characteristics should have a Type Certificate requirement or old guys who have flown many, many, many small airplanes with really good control characteristics should not be allowed to fly them. The controls may not work and they don't crash well. Bad combination.

 

Jim

 

 

[kasper]

Garfly,Yes, in my country the Dutch Roll was taught as a coordination maneuver. I didn't worry about the video because he explained what he was doing well (side slip) regardless of what he called it. As Nev says the big iron boys have their own language.

 

Nev,

 

Does your Aviation Agency require a Type Certificate for big (12,500 US pounds) airplanes? I think the new little airplanes with weird control characteristics should have a Type Certificate requirement or old guys who have flown many, many, many small airplanes with really good control characteristics should not be allowed to fly them. The controls may not work and they don't crash well. Bad combination.

 

Jim

CASA is our Australia Aviation Agency and to put an aircraft in the 5,700kg(12,500lb) class onto the national aircraft register a type certificate will be required - either an Australian one of an accepted one from another country/authority.

However, Australia has three currently very distinctly different regimes for what falls within recreational flying:

 

1. Type certificated/LSA aircraft with national registration light aircraft

 

2. Homebuilt aircraft with national registration light aircraft

 

3. Factory or homebuilt RAA aircraft - not national registration but on a separate recreational register - held by RAA or HGFA operating under the CASA delegations

 

The last area of non-national registration holding aircraft are very different in terms of certification requirements and 'old guys' need to hold a separate RAA/HGFA pilot certificate which requires additional training from the PPL so the 'old guys' are pretty safe ... on average ;-)

 

 

[Oscar]

Garfly,Y? I think the new little airplanes with weird control characteristics should have a Type Certificate requirement or old guys who have flown many, many, many small airplanes with really good control characteristics should not be allowed to fly them. The controls may not work and they don't crash well. Bad combination.

 

Jim

Perhaps you should acquaint yourself with the safety statistics for Jabirus in your own country: they score as well as the top light aircraft, and better than the C172.

 

 

[Contact Flying]

Oscar,

 

Yes I have heard that. Haven't had a chance to fly one.

 

Contact

 

 

[Oscar]

In certification parlance, Dutch roll results from relatively weaker positive directional stability as opposed to positive lateral stability (thank you, WIKI, for the concise definition).. It is NOT a pilot manouver, it is an inherent characteristic of the aircraft.

 

Dutch Roll usually results from excessive lateral stability - usually the result of excessive dihedral. The aircraft overcompensates for a disturbance to its lateral stability and as a result, yaws as it recovers, then over-recovers, and the consequent overcompensation causes a yaw in the opposite direction. Hence, it waddles through anything more than completely still air like a hemorrhoidal duck.

 

I once flew in a Moraine Saulnier Rallye 180 ( if my memory serves me correctly) from Canberra - Tocumwal and return; the thing Dutch Rolled like a drunken sailor and had both occupants close to sea-sickness. The l/e flaps were constantly oscillating in and out. It was a most uncomfortable trip - and the PIC was a CASA approved TEST pilot, no mug. It certainly climbed out like a homesick angel but thereafter flew like a squid dancing.

 

Dutch Roll is an aerodynamic condition - NOT a pilot-initiated flight sequence. It is recognised - and tested for - in certification. Any aircraft that self-excites Dutch Roll should not pass certification. Look at FAR 23 testing for Dutch Roll.

 

 

[Oscar]

Oscar,Yes I have heard that. Haven't had a chance to fly one.

Contact

Try a J230. You may be very surprised at how civilized it is.

 

 

[facthunter]

The telltale signs would be things like hiwing WITH dihedral and/or sweep back. Lots of stability do not a nice aeroplane make. There's a good case for fairly neutral stability. (in my view). Disposition of mass along fuselage or wings is important too. The further towards the extremities the more problems. Nev

 

 

[djpacro]

Dutch Roll is an aerodynamic condition - NOT a pilot-initiated flight sequence.

Just a little annoying for engineers but if many people use that term for a useful flight exercise then so be it. I did some training once with an ex-USAF Colonel whose nickname was Dutch - he loved to call his wave the Dutch salute and ..... sorry, but he would be quite entitled to roll around the floor and call that a Dutch roll.

 

Dutch Roll is an aerodynamic condition .... recognised - and tested for - in certification. Any aircraft that self-excites Dutch Roll should not pass certification. Look at FAR 23 testing for Dutch Roll.

The certification requirement is for a specific level of positive DR stability. The PC-9 is one type which does not meet that requirement (at high altitude). The Airtourer is one example of a type which exhibits an annoying DR in a little bit of turbulence - I've always wanted a bigger rudder and fin on an Airtourer.

[facthunter]

Dutch roll can be initiated by turbulence or control input. To be a problem it has to be divergent. You can train to control it manually and where applicable it is part of a conversion on type. Usually Yaw dampers are used. If you do the wrong manual input it may go on it's back, which encourages you to be careful. Nev

 

 

[kaz3g]

kaz3g,Thanks for the video. That was a very good lesson. In side by side airplanes, remember that we line up the longitudinal axis with the center line by looking straight ahead. Army helicopter instructors call it putting the center line between our legs. We can't look over the nose. We instructors are not always careful to point that out. On paved fields, notice that the tire marks are left of the center line because pilots sitting in the left seat are looking over the prop and squeeking it down a little crooked. Nasty in tail wheel, but most tail wheel airplanes are tandem here in US.

 

Also in our western states, pilots occasionally run out of fuel in the afternoon trying to get to a runway more aligned with the wind during summer afternoons when winds often become extreme. A good solution to this problem is to land across the runway angled more into the crosswind. We still have to crab then slip or better side slip all the way down. And we have to use the apparent brisk walk rate of closure or some power/pitch approach to guarantee getting down in the 1,000 feet (300 and some meters) between the downwind corner of the runway and the upwind big airplane touchdown zone marking.

 

Thanks again,

 

Contact

Hi Contact

 

My Auster is a Taylorcraft derivative (side by side with heel operated cable-drum brakes) with 36' wingspan and an 0-320. The C of G is very definitely behind the mains. It has a placarded stall FE of 26 knots, a demonstrated max XW of 9 knots and bungy suspension that stores a lot of energy.

 

So, over the 7 years I have owned it, I have learned a little about finding ways to land (more) into wind, or finding grass to land on instead of bitumen, but there are still many days when the wind is howling diagonally across both runways and I just stay home.

 

Kaz

 

 

[Guest gannett]

Its no secret my instructor told me on my first landing lesson to use the ailerons to put both wheels down at the same time and rudder to keep on the centre line.

 

 

[dutchroll]

Its no secret my instructor told me on my first landing lesson to use the ailerons to put both wheels down at the same time and rudder to keep on the centre line.

And he's absolutely correct for a normal into wind landing (which is all you should be doing in the early days).

 

 

[Guest gannett]

It works for crosswind as well, you just crab down the centre line and square up just before the wheels touch down.

 

 

[DWF]

Its no secret my instructor told me on my first landing lesson to use the ailerons to put both wheels down at the same time and rudder to keep on the centre line.

You weren't flying a taildragger in a crosswind then.

 

 

[Kamloops]

Sometimes you just cannot touch down both mains at once...

 

Go practice crosswind landings gannett.

 

Then get back to us how that instructors teaching worked out for you?

 

Hopefully its just a very mild ground loop and no damage is done....just a little bit embarrassing is all.

 

 

[Contact Flying]

In strong crosswinds the student can easily see what is going on in the side slip to landing on the upwind main wheel. There is no question about controlling drift with bank while keeping the longitudinal axis lined up with the center line with dynamic proactive rudder.

 

The difficulty and confusion comes with the slight crosswind or even no wind. The easy solution to this confusion is to fly the approach exactly as if we had a significant crosswind. Keep the wing level with aileron or at a slight bank if necessary to stop drift. Walk the rudder just right, just left, etc. to keep the center line between our legs. If the center line is between our legs, it will be between the instructors legs (longitudinal axis will be lined up.)

 

In this way we don't have to over think it. All approaches become the same approach, as to how we handle the ailerons and rudders. If there is a slight crosswind, we will land first on the upwind main wheel. If no crosswind component, we will land on both main wheels.

 

Instructors, we need to start the student's crosswind training with enough crosswind to actually see the side slip needed to stop drift and the amount of opposite rudder needed to get down with the longitudinal axis aligned with the direction of motion or center line. Starting them on a slight crosswind is mean and ugly.

 

 

[Kamloops]

https://www.google.ca/url?sa=t&source=web&rct=j&url=http://m.youtube.com/watch%3Fv%3DDLeVy2gC2v0&ved=0ahUKEwis4oPlm6_JAhVWKYgKHQraCTMQtwIIJjAE&usg=AFQjCNFAgZaOnHFILDL66zPoq0Y8OW1afg&sig2=amPYFpWVh0lCsq5M5A17wA

 

Lol.....if he had passengers i wonder how wet their underwear were after.....

 

 

[facthunter]

Let's not forget in the early days of every plane being a tailwheel, the fields were all over and you landed into wind, because you could.

 

Slipping into wind and landing on one wheel makes good sense, for a basic trainer especially a high wing. Some students really resist doing that. It's easy enough at the point of touchdown but a little more complex if the wind is strong enough to have to maintain it for a while after touchdown. Nev

 

 

[dutchroll]

It works for crosswind as well, you just crab down the centre line and square up just before the wheels touch down.

Mmmm....that's kinda grossly simplified when it comes to how a crabbed approach works.

Crabbed crosswind approach & landing

 

• The aircraft is established on final, on the extended centreline, wings level.
   
   
  
• To achieve this the heading is obviously offset for drift.
   
   
  
• In a large aircraft, you must be laterally displaced slightly upwind due to your seating position and the gear geometry involved with "kicking it straight".
   
   
  
• Small, balanced heading corrections are used to adjust as required, but overall the wings remain level during the approach.
   
   
  
• At flare height the flare is commenced, and simultaneously a smooth rudder input applied to remove the drift (or crab angle) and align the aircraft with the runway.
   
   
  
• Opposite aileron is needed to keep the wings level.
   
   
  
• In a perfect world, as the aircraft reaches alignment with runway heading, the main wheels both touchdown. Regrettably the world is not always perfect.
   
   
  

 

 

Problems:

 

- if the flare is misjudged, the aircraft may drift across the runway excessively while being aligned using rudder.

 

- timing needs to be very good as the aircraft may still have crab angle on at touchdown. Usually not disastrous for the plane, but makes for a rough touchdown.

 

- difficult manoeuvre to get exactly right, and not really one for beginners.

 

Sideslip crosswind approach and landing

 

• The aircraft is established on final on the extended centreline, wings level, offset for drift.
   
   
  
• At an appropriate height on final approach, the aircraft is established in a sideslip. Opinions on this vary, but I'd suggest get it sorted soon after you roll out on final on the extended centreline.
   
   
  
• Rudder is applied to align the aircraft heading with the runway, and aileron is used to prevent drift (resulting in a bank angle being established, low wing into wind).
   
   
  
• At flare height the flare is commenced, with the into wind main wheel touching down first.
   
   
  
• Aileron is adjusted to "gently" lower the other wheel onto the runway (yeah I know - I'm just giving you the theory, right?).
   
   
  

 

 

Problems:

 

- not a comfortable way to fly.

 

- poor technique for geometry limited aircraft, ie, those which can't afford to have much of a bank angle on at touchdown.

 

In the CT4 we were taught and used sideslip. In the Pitts I certainly use sideslip too. Believe it or not, in the C130 Hercules you also used sideslip.

 

In a big jet you always use a crabbed approach. In some other aircraft you do too.

 

 

[kasper]

Mmmm....that's kinda grossly simplified when it comes to how a crabbed approach works.Crabbed crosswind approach & landing

 

• The aircraft is established on final, on the extended centreline, wings level.
   
   
  
• To achieve this the heading is obviously offset for drift.
   
   
  
• In a large aircraft, you must be laterally displaced slightly upwind due to your seating position and the gear geometry involved with "kicking it straight".
   
   
  
• Small, balanced heading corrections are used to adjust as required, but overall the wings remain level during the approach.
   
   
  
• At flare height the flare is commenced, and simultaneously a smooth rudder input applied to remove the drift (or crab angle) and align the aircraft with the runway.
   
   
  
• Opposite aileron is needed to keep the wings level.
   
   
  
• In a perfect world, as the aircraft reaches alignment with runway heading, the main wheels both touchdown. Regrettably the world is not always perfect.
   
   
  

 

 

Problems:

 

- if the flare is misjudged, the aircraft may drift across the runway excessively while being aligned using rudder.

 

- timing needs to be very good as the aircraft may still have crab angle on at touchdown. Usually not disastrous for the plane, but makes for a rough touchdown.

 

- difficult manoeuvre to get exactly right, and not really one for beginners.

 

Sideslip crosswind approach and landing

 

• The aircraft is established on final on the extended centreline, wings level, offset for drift.
   
   
  
• At an appropriate height on final approach, the aircraft is established in a sideslip. Opinions on this vary, but I'd suggest get it sorted soon after you roll out on final on the extended centreline.
   
   
  
• Rudder is applied to align the aircraft heading with the runway, and aileron is used to prevent drift (resulting in a bank angle being established, low wing into wind).
   
   
  
• At flare height the flare is commenced, with the into wind main wheel touching down first.
   
   
  
• Aileron is adjusted to "gently" lower the other wheel onto the runway (yeah I know - I'm just giving you the theory, right?).
   
   
  

 

 

Problems:

 

- not a comfortable way to fly.

 

- poor technique for geometry limited aircraft, ie, those which can't afford to have much of a bank angle on at touchdown.

 

In the CT4 we were taught and used sideslip. In the Pitts I certainly use sideslip too. Believe it or not, in the C130 Hercules you also used sideslip.

 

In a big jet you always use a crabbed approach. In some other aircraft you do too.

And if you are in aircraft where slip is not possible you crab like there is no tomorrow and straighten up in the flare. eg weightshift - you have to do a turn in the flare and remember definitely do not kick it straight on the feet:yikes: or in a Pou du Ciel type its even more fun depending on if the tailwheel/nosewheel is connected to the rudder - hilarious having left pedal for the wheel and right stick for the rudder - must remember DO NOT overthink, just fly the plane:plane:

 

 

[dutchroll]

I don't count weightshifters as "aircraft", but rather "loose assemblies of tubes and rags which get blown about by the wind".

 

 

[IBob]

Thank you, Dutchroll.

 

I have been reading this thread with growing frustration (tinged with relief that I don't know enough to have an opinion, which it seems would be promptly shot down anyway).

 

I found your post above wonderfully clear and concise.

 

And, at last, the acknowledgement that in some aircraft you do this, but in others you do that.

 

 

[facthunter]

The correct techniques are certainly varied. Some pilots do better crosswinds if you don't draw their attention to the fact there is a crosswind.

 

You can do a "mix" of both and many little kicks and tricks as well. The main aim with U/L's is not to land on the nosewheel, (if you have one) Try not to land with the wheel(s) going in a different direction to what you are and don't let the wind get under the upwind wing. A crab approach with kick straight if not timed well hardly achieves anything, as with a very light plane it goes with the wind almost instantly so keep the wheel down. One saving grace is the wind strength often drops off a bit near the ground. Nev