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"We are the protagonists of our stories called life, and there is no limit to how high we can fly."


Type rated on A330, B747-400, B747, B757, B767, B737, B727. International Airline Pilot / Author / Speaker. Dedicated to giving the gift of wings to anyone following their dreams. Supporting Aviation Safety through training, writing, and inspiration.

Tuesday, January 15, 2013

The Stick and the Yoke

I received emails concerning the airbus often... this is one such comment that was worth discussing again. 

Fact or Fiction on the Airbus?

 

"The bus is a bit tricky in a cross wind landing or gusty conditions. This isn't the joystick's fault, but the fly by wire is slower than humans to react to pitch & roll excursions. It also changes control laws in the flare, adding to the fun.

Just try to remember that Fifi is trying to maintain the last attitude you had dialed in but has a lazy way of responding to the bumps. The closer you are to the ground the less willing you are to trust her!

It takes time to not stir the pot, but it can be learned.  As for the stick itself, it is great.
No yoke to hit your knees on, and gives room for the most civilized thing the French ever did, putting a tray table in front of the drivers.

Feedback? None, you are fighting a spring, like a computer joystick.
Only your joystick moves, so no "following the other guy through" on the controls.

Autotrim?  Yes, up to 30 degrees bank and to the pitch limits for the phase you are in.
The bus will hold the load factor and roll rate you input, up to the limits of the computers.
The less you touch the stick, the better off you are in most cases."

My Thoughts: 

The stick is not really the mystery or challenge that one might think. The stick has nothing to do with the computer logic of the plane. The stick is only the method of telling the plane what we want to do, not how to do it. 


A Check Airman's thoughts 
and Tips on Landing: 

Only the pitch law is changed below 100 feet, not all flight control laws.

For best results at 50 feet squeeze in enough rudder to align with the runway and only enough bank to counter drift (remember sidestick is roll rate not aileron!) aileron is added automatically to keep the bank.  Takes more rudder and less bank than most expect.
 
After touchdown, put in a little upwind stick to keep that wing down (it's direct control now).

I've done 50 knot xwinds in the sim like this non problem...

For strong crosswinds, consider the longitudinal pivot point is 100 feet behind you. You may need to put your seat on the upwind side a little so that you're  on the centerline after the de-crab.

So there you have it.

More on the bus to come.
Enjoy the Journey!
XO Karlene

12 comments:

  1. I LOVE these posts. My favorites! I don't understand anything, but I think they are super! ^^

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    1. I am so glad you are easily entertained. lol. YOU are a pilot! Thanks Alex. One day, you will!

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  2. It's always interesting to read about this stuff. I've Kit Fox, X-Air, C172, and Cherokee 140. No computer laws to worry about on those. Just good ol stick n rudder and mechanical linkages.

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    1. Kevin, never underestimate the power of good old stick and rudder. One day future generations won't even know what those terms mean. Happy Flying!

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  3. Thanks, Karlene. Fun, interesting and most informative. I've never flown an AB, real or in a simulator (and don't really expect the opportunity), but a bit more understanding of the computer(s) vs. the human hand on that stick is great fun. From the PAX point of view, I really glad that you understand this stuff. Thanks for the wonderful post. -C (Cedarglen)

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    1. Thank you Craig! I think understanding comes from continually studying. There is so much to know and so little time. But as far as the passengers go... yes, it's so important to know. We owe them that much.
      Thanks for the comment.

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  4. So, do your prefer the 'positive feedback' from the Boeing approach or the Airbus 'little spring'...?

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    1. I like the feel. But that's because I know what it feels like. lol.

      They say that the airbus can take a lousy pilot and make them average. Or take an excellent pilot and make them average, too. :)

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  5. Great article! I have been in an A320 sim and it was different getting used to rate of roll rather than aileron control. I did like the space the side stick offeres in front of you but I must ask, since you have flown aircraft with both rate of roll and aileron control, which one do you prefer? I don't recall doing crosswind landings while on the A320 sim but right now i fly the ERJ 145 and like the fact that this aircraft is aileron control. Im sure both have their pros and cons. Stephen Rocha

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    1. Thank you! I think I like aileron control. But only because that's what I'm use to. I think flying in general the FBW plane is smarter than we are. It just has more data on its condition and can anticipate. It's more efficient, I should say. But landing in that crosswind, there is nothing like ailerons.
      But it's something you get used to fairly quickly. Thanks so much for your comment!

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  6. While it wasn't a contributing factor, after the AFR447 accident I wondered if there was a reason Airbus hadn't made the joysticks move together. Sure, I can understand that maybe it wasn't technically feasible when the A320 was designed, but nowadays? A little motor and some circuitry. How hard can it be? Is there ever a time in normal operation when the joysticks would intentionally be given conflicting commands?

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    1. Adam, We can bypass the other pilot's stick, and lock it out. This design was to take control in the event of a stick malfunction. But not under a normal circumstances.

      I'm not an engineer, but I would suspect that due to the fact there is no cable linkage, that the sticks are not going to move with each other. I don't know how they would create that movement in relation to the other stick. But, there is a very loud "Dual input" warning when both sticks are used at the same time.

      Thanks for your comment.

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