Full sidetick 320 in gusts
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Full sidetick 320 in gusts
hello airbus pilots,
i have a quick question. i flew recently an ils approach in gusty conditions, so in 2000ft agl nearly 50kts with a very high gust rate. So i disconnected the ap and athr and flew at 2000agl manual, fd on. coming from th3 737 ng i realised 2 things:
one or two times i had a full stick deflection which i felt was necessary in the bank. is that a normal experience in gusty winds? In my 737 i never had a full deflection.
second thing was the fd. seemed sometimes to jump aside, so very quick and not smooth
landing was fine, i love the bus in crosswind conditions near the ground.
how do handle that, let the ap do the job till minima? i dont wanna take the fun out but seems the best to be right?
cheers!
i have a quick question. i flew recently an ils approach in gusty conditions, so in 2000ft agl nearly 50kts with a very high gust rate. So i disconnected the ap and athr and flew at 2000agl manual, fd on. coming from th3 737 ng i realised 2 things:
one or two times i had a full stick deflection which i felt was necessary in the bank. is that a normal experience in gusty winds? In my 737 i never had a full deflection.
second thing was the fd. seemed sometimes to jump aside, so very quick and not smooth
landing was fine, i love the bus in crosswind conditions near the ground.
how do handle that, let the ap do the job till minima? i dont wanna take the fun out but seems the best to be right?
cheers!
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Have a look at Airbus FCB024-AIRCRAFT HANDLING IN FINAL APPROACH.
Regarding full sidestick deflections, Mr. Airbus says therein:
So I guess bumping the stops is bound to happen from time to time by design...
Regarding full sidestick deflections, Mr. Airbus says therein:
The sidestick's ergonomical design is such that the stop at full deflection is easily reached. This may give the pilot the impression that the aircraft is limited in roll authority, because there is a time delay before the pilot feels the result of his/her action. On conventional aircraft, due to the control wheel inertia, the pilot needs considerably more time to reach the flight control stop.
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A320 gamestick lateral input is a roll rate demand not a control surface demand. Hence its easy to have
full stick deflection sometimes in very heavy gust situations - even though these would vary rarely need
it. You'd find in Direct Law your control inputs would be like the 737 - albeit rather more sensitive. Try it
in the sim next recurrent but don't overcontrol by trying to follow the FD. Turning it off helps a lot - the
bird is much more useful.
full stick deflection sometimes in very heavy gust situations - even though these would vary rarely need
it. You'd find in Direct Law your control inputs would be like the 737 - albeit rather more sensitive. Try it
in the sim next recurrent but don't overcontrol by trying to follow the FD. Turning it off helps a lot - the
bird is much more useful.
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Hi Speedwinner,
I agree with the previous, especially Slasher's comment
Sometimes in gusty conditions, a small side stick input may command full ailerons in an attempt to give you the requested roll rate. Any more side stick will have no effect - giving the impression that it is not responding - hence a tendency to over control and hit the stops. Try and keep the roll rate selections small and let the FBW computers decide how much aileron you need.
I agree with the previous, especially Slasher's comment
lateral input is a roll rate demand
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Hi, Speed!
I know what you're talking about: when I had to transition from B777 to A320 I found that an horrible shortcoming. As a matter of fact, one of the worst things to get used on the Bus.
It won't kill you, but it's scaring and will sometime prompt 'dual input' from your fellow - remember that LH go around on windy cond in Hamburg couple of years ago.
Fortunately, I'm back and happy on the triple.
It won't kill you, but it's scaring and will sometime prompt 'dual input' from your fellow - remember that LH go around on windy cond in Hamburg couple of years ago.
Fortunately, I'm back and happy on the triple.
Your playing with it 
remember to treat it like another persons whatsit and you will find you don't need to touch the thing.
Btw... Roll rate
remember to treat it like another persons whatsit and you will find you don't need to touch the thing.Btw... Roll rate
Last edited by Bula; 5th Feb 2013 at 21:17.
In very windy conditions you may well have to hold the sidestick against a left or right stop for a couple of seconds before anything seems to happen. However, remember that there are always two of you flying an Airbus - even with the A/P out - you and the flight control system. Even in manual; the aircraft will already be recovering the roll - maybe already using max control deflection - so your input may have no extra effect for a while until the gust subsides. The aircraft will be recovering as 'fast' as it can in the circumstances - but not overstressing the airframe in the process.
It is a very different technique to using the traditional mechanical yoke, but I find that once you understand the concept that in manual control you are effectively guiding an autopilot all the time, it becomes easier to get the hang of.
I think of it like this: The autopilot disconnect in an Airbus changes where the autopilot gets its navigation commands from. With 'Autopilot in' the navigation commands come from the FMGS/FCU. With 'Autopilot out' the navigation commands come from you and your sidestick, but the flight control system is still helping to fly the plane.
Took me a while to work this out - and of course; no-one ever tells you.
It is a very different technique to using the traditional mechanical yoke, but I find that once you understand the concept that in manual control you are effectively guiding an autopilot all the time, it becomes easier to get the hang of.
I think of it like this: The autopilot disconnect in an Airbus changes where the autopilot gets its navigation commands from. With 'Autopilot in' the navigation commands come from the FMGS/FCU. With 'Autopilot out' the navigation commands come from you and your sidestick, but the flight control system is still helping to fly the plane.
Took me a while to work this out - and of course; no-one ever tells you.
Last edited by Uplinker; 8th Feb 2013 at 08:18.
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No-one tells you because it does not work like that..... The AP commands, or the side stick commands, talk directly to SEC and ELAC.... they move the surfaces.
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Uplinker
+1
In any normal aircraft, you have three potential inputs (Capt, FO, AP) that move 2 interconnected control yolks.
On an AB, you have the same three, two of which move only their own sidesticks, and one acting in the blind. Actually all three are acting in the blind as you can't see what the other pilot is doing unless you take your eyes off the runway ahead of you.
On AB with the AP off, actually the AP is still on, in mode called attitude hold or control stick steering in other aircraft. Where ever the aircraft is pointed in pitch and roll, the aircraft tries to maintain those positions. If a gust hits you and tries to roll the aircraft, the flight control computers put roll input to try to maintain your angle of bank. Unfortunately AB decided not to communicate this to you. If you input roll command as well, the aircraft might already be at the control stops, hence, no reaction from the aircraft.
The same with your flying partner. If the aircraft hits a roll gust, he will input roll command to the stick, and you can't see it either. Hence the "dual input", and/or "priority left".
AB does great in gusty conditions, you just have to get used to it.
+1
In any normal aircraft, you have three potential inputs (Capt, FO, AP) that move 2 interconnected control yolks.
On an AB, you have the same three, two of which move only their own sidesticks, and one acting in the blind. Actually all three are acting in the blind as you can't see what the other pilot is doing unless you take your eyes off the runway ahead of you.
On AB with the AP off, actually the AP is still on, in mode called attitude hold or control stick steering in other aircraft. Where ever the aircraft is pointed in pitch and roll, the aircraft tries to maintain those positions. If a gust hits you and tries to roll the aircraft, the flight control computers put roll input to try to maintain your angle of bank. Unfortunately AB decided not to communicate this to you. If you input roll command as well, the aircraft might already be at the control stops, hence, no reaction from the aircraft.
The same with your flying partner. If the aircraft hits a roll gust, he will input roll command to the stick, and you can't see it either. Hence the "dual input", and/or "priority left".
AB does great in gusty conditions, you just have to get used to it.
Er, Tyro and USMC, if you re-read my post carefully and take note of the punctuation, use of italics and words I used (such as "effectively", and "I think of it like this...."); I think you'll find that's exactly what I was saying!
However, I have changed a word to hopefully make it clearer.
Tyro misses out the accelerometer feedbacks, which send commands to the flight control computers to keep the aircraft on the path you or the FMGS commanded. This is the part of the system that is always flying the plane with you, and is how the aircraft will try to correct for gusts etc. even when the autopilot is disconnected.
However, I have changed a word to hopefully make it clearer.
Tyro misses out the accelerometer feedbacks, which send commands to the flight control computers to keep the aircraft on the path you or the FMGS commanded. This is the part of the system that is always flying the plane with you, and is how the aircraft will try to correct for gusts etc. even when the autopilot is disconnected.
Last edited by Uplinker; 8th Feb 2013 at 08:26.
Ah, sorry USMC - I'm not up with the internet lingo !
My apologies.
My apologies.
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On AB with the AP off, actually the AP is still on, in mode called attitude hold or control stick steering in other aircraft. Where ever the aircraft is pointed in pitch and roll, the aircraft tries to maintain those positions.
If a gust hits you and tries to roll the aircraft, the flight control computers put roll input to try to maintain your angle of bank. Unfortunately AB decided not to communicate this to you
SPEEDWINTER
try this the next time, which is in my opinion better explained than any airbus text: allow a sec to the FCS to counter the gust. Wait just a moment before you make an input in the opposite direction of the roll. The roll will be arrested, or almost, by the ELAC, then you make your input. Easy. If you don't, you will be like mixing mayonnaise.
Airbus says that the airplane can rolll at a 15º per sec rate and blabla, but it cannot avoid bank angle from changing. Actually that would be weird. But it resists. Just let it do the job, or most of it, then do your input. Otherwise your input and the FCS' will be simultaneous and added to each other and here we go mayonnaise...
and that is the secret. Like an augmented lateral stability. Try this and give me feedback if you have gusts one of these days
How is this system an advance ?
Setting aside the non connected sticks, unbackdriven autothrottles and hard limits for a minute..
Seriously, you would think a sidestick control system would / could be very responsive, instead the FBW filtering effectively seems to provide a sluggish, unpredictable response.
Full deflection in a Boeing is almost unthinkable, but more importantly, what you input is what you get, predictable and no second guessing, every time.
Setting aside the non connected sticks, unbackdriven autothrottles and hard limits for a minute..
Seriously, you would think a sidestick control system would / could be very responsive, instead the FBW filtering effectively seems to provide a sluggish, unpredictable response.
Full deflection in a Boeing is almost unthinkable, but more importantly, what you input is what you get, predictable and no second guessing, every time.
What is interesting is that several people have described exactly what the Airbus FBW system does, then others come on and say that's rubbish and go on to describe what they think it does.....and their description amounts to the same but with different words!
All that is being argued here is terminology: I say that even with AP out "it's like the AP is still in...but the Navigation commands are coming from different places". Others say no that's rubbish with the AP out the ELAC is still helping, but people: the principle is the same.
For example:
...is not really rubbish is it? Read it again carefully, Micro, I think it describes what the FBW does very well.
Silton, This is what myself and others are trying to get across. The Airbus FBW system is different to conventional mechanical flight controls. It flies differently - like the autopilot is always in. Yes; a Tornado, for example, has a very responsive FBW system, because it is a fighter jet and may need to execute escape or kill manoeuvers at high 'G'. A passenger jet does not want a fighter like response, it is "sluggish" partly for passenger comfort, and partly never to exceed it's design limit of 2.5G. With mechanical controls, one could overstress the aircraft by commanding full deflection. With the Airbus the FBW will not allow the airframe to be overstressed*, and it will try to maintain whatever attitude you last commanded. This needs a different technique when handflying the FBW Airbus. BUT it's something that no trainer has ever taught (me), I've only ever been told "hold the sidestick only on the top/only on the bottom/don't touch it etc etc, which are completely unhelpful. I've seen senior Captains overcontrolling and getting into PIO's because they too do not understand how the FBW works, and have never had it explained to them. Understanding what the FBW is doing helps one to handfly the aircraft much better.
*PS: Before I get shot down again; most Airbus rudders are mechanically linked to the rudder pedals. Therefore it is possible to overstress the rudder.
All that is being argued here is terminology: I say that even with AP out "it's like the AP is still in...but the Navigation commands are coming from different places". Others say no that's rubbish with the AP out the ELAC is still helping, but people: the principle is the same.
For example:
Quote:
On AB with the AP off, actually the AP is still on, in mode called attitude hold or control stick steering in other aircraft. Where ever the aircraft is pointed in pitch and roll, the aircraft tries to maintain those positions.
Sorry marine, but that is rubbish. Are you type rated in the 320??
On AB with the AP off, actually the AP is still on, in mode called attitude hold or control stick steering in other aircraft. Where ever the aircraft is pointed in pitch and roll, the aircraft tries to maintain those positions.
Sorry marine, but that is rubbish. Are you type rated in the 320??
Silton, This is what myself and others are trying to get across. The Airbus FBW system is different to conventional mechanical flight controls. It flies differently - like the autopilot is always in. Yes; a Tornado, for example, has a very responsive FBW system, because it is a fighter jet and may need to execute escape or kill manoeuvers at high 'G'. A passenger jet does not want a fighter like response, it is "sluggish" partly for passenger comfort, and partly never to exceed it's design limit of 2.5G. With mechanical controls, one could overstress the aircraft by commanding full deflection. With the Airbus the FBW will not allow the airframe to be overstressed*, and it will try to maintain whatever attitude you last commanded. This needs a different technique when handflying the FBW Airbus. BUT it's something that no trainer has ever taught (me), I've only ever been told "hold the sidestick only on the top/only on the bottom/don't touch it etc etc, which are completely unhelpful. I've seen senior Captains overcontrolling and getting into PIO's because they too do not understand how the FBW works, and have never had it explained to them. Understanding what the FBW is doing helps one to handfly the aircraft much better.
*PS: Before I get shot down again; most Airbus rudders are mechanically linked to the rudder pedals. Therefore it is possible to overstress the rudder.
Last edited by Uplinker; 9th Feb 2013 at 10:28.
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Fortunately, I'm back and happy on the triple.
remember to treat it like another persons whatsit
Not exactly Airbus procedure!
Stilt - nope. Scary huh.
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Attitude hold and control stick steering are not techniques that airbus is using, but the name given to AP on other aircraft that accomplish the same thing.
Take you hand off the stick, feet on the floor. What are you commanding on the 320? No input? No, you are commanding 0 pitch rate, 0 roll rate, and 0 yaw rate. Any external forces (wind) that provide something other than zero, the FBW system will try to counteract. But, if the aircraft ends up in a 10 deg bank, the FBW does not roll the aircraft back to zero. In smooth air, it effectively holds whatever pitch and roll angle that you set.
Side sticks not connected. No problem if your flying partner has 8K hours. Sometimes a problem with low time pilots. If both sticks are moved at the same time you get a "dual input" oral warning, but the command of both sticks are "added" together. Both sticks have a little red button that locks out the other stick. Two uses for the button. If a stick is defective and puts in a bad input, you can take priority ("Priority left") and takeover. Hold the button for 42 seconds and the other stick is locked out for the remainder of the flight.
I wish the sticks were connected, I wish the throttles moved, and I wish Boeing could put a table in the cockpit so I don't have to eat on my thighs
Take you hand off the stick, feet on the floor. What are you commanding on the 320? No input? No, you are commanding 0 pitch rate, 0 roll rate, and 0 yaw rate. Any external forces (wind) that provide something other than zero, the FBW system will try to counteract. But, if the aircraft ends up in a 10 deg bank, the FBW does not roll the aircraft back to zero. In smooth air, it effectively holds whatever pitch and roll angle that you set.
Side sticks not connected. No problem if your flying partner has 8K hours. Sometimes a problem with low time pilots. If both sticks are moved at the same time you get a "dual input" oral warning, but the command of both sticks are "added" together. Both sticks have a little red button that locks out the other stick. Two uses for the button. If a stick is defective and puts in a bad input, you can take priority ("Priority left") and takeover. Hold the button for 42 seconds and the other stick is locked out for the remainder of the flight.
I wish the sticks were connected, I wish the throttles moved, and I wish Boeing could put a table in the cockpit so I don't have to eat on my thighs