Flight Controls
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Flight Controls
Hello !
I have questions about flight controls on A320, B777 and A380.
If ALL flight computers fails on the A320 or A380, (ELAC+SEC+FAC..) or the B777 (ACES), there is no electrical signals to computers when pilot imput to side stick or yoke. So, can we do still control the aircraft without any flight computers considering that we have Hydraulic ?
If yes, the answer is probably the Mechanical backup for A320 and B777, and Electrical Flight Controls for the A380, right ?
For the A380, is that true that the pitch trim is set through the PITCH TRIM switch just BEFORE TAXI as same as the A320 ?
Or is it just used in the case of Hydraulic failure as the A380 have some electrical flight controls in the case of HYD failure ?
And finally, I want to know if the B777 flight controls are the same as the A380 or the A320. To be more precise, I want to know if the B777 have only Hydraulic+ Mechanical flight controls as the A320, or Hydraulic + Electrical as the A380 ? Or both ? Hydraulic + ELECTRICAL and MECHANICAL in the case of an malfunctions.
Thanks !
I have questions about flight controls on A320, B777 and A380.
If ALL flight computers fails on the A320 or A380, (ELAC+SEC+FAC..) or the B777 (ACES), there is no electrical signals to computers when pilot imput to side stick or yoke. So, can we do still control the aircraft without any flight computers considering that we have Hydraulic ?
If yes, the answer is probably the Mechanical backup for A320 and B777, and Electrical Flight Controls for the A380, right ?
For the A380, is that true that the pitch trim is set through the PITCH TRIM switch just BEFORE TAXI as same as the A320 ?
Or is it just used in the case of Hydraulic failure as the A380 have some electrical flight controls in the case of HYD failure ?
And finally, I want to know if the B777 flight controls are the same as the A380 or the A320. To be more precise, I want to know if the B777 have only Hydraulic+ Mechanical flight controls as the A320, or Hydraulic + Electrical as the A380 ? Or both ? Hydraulic + ELECTRICAL and MECHANICAL in the case of an malfunctions.
Thanks !
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On the 777, there will be limited roll control through a spoiler pair (4 & 11?) which are controlled by cables. I also seem to remember that the back up stab trim does not go through the ACE's.
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Thank you for taking the time to answer me!
You are right, after your answer, I did a research, and you are right: If all electric power is lost AND HYD pressure is available, stabiliser is operative with alternate pitch trim levers, which mechanically move directly the stabilizer, and also you have Spoilers 4 & 11 which are mechanically controlled through a cable from the control wheel, and also the rudder.
So, the 777 is ok, but in the case of a complete electrical loss on the A380, what are the backup ?
Because if we have a TOTAL HYD loss on the A380, RAT supplies power to EHA and EHBA, (not to Blue or Green system as the 320 or 330 family) which is just some Electrical Flight Controls, that powers with reduced performance to Ailerons, Elevator, Rudder, some spoilers and slats.
So, if we have a COMPLETE ELECTRICAL loss on the A380, we have RAT which supplies Electric to the aircraft and to electrical flight controls.
But if we have a TOTAL FLIGHT COMPUTERS failure ? (PRIMary, and SECondary), how can we control this big bird ? Because I know that the A380 don't have mechanical control, there is a pitch trim switch and not a wheel as the A320, but I thought that this switch is also electrically powered, so we can not use this switch in the case of a complete loss of all flight computers. And for the Rudder ? I think it is also powered from flight computers (P1,S1, P2,S2) for the upper rudder, and (P1 ,S1, P3, S3) for the lower rudder, but moved thanks to Yellow and Green Hydraulic OR Electrically (EHA), but we can't move it due to loss of flight computers right ?
You are right, after your answer, I did a research, and you are right: If all electric power is lost AND HYD pressure is available, stabiliser is operative with alternate pitch trim levers, which mechanically move directly the stabilizer, and also you have Spoilers 4 & 11 which are mechanically controlled through a cable from the control wheel, and also the rudder.
So, the 777 is ok, but in the case of a complete electrical loss on the A380, what are the backup ?
Because if we have a TOTAL HYD loss on the A380, RAT supplies power to EHA and EHBA, (not to Blue or Green system as the 320 or 330 family) which is just some Electrical Flight Controls, that powers with reduced performance to Ailerons, Elevator, Rudder, some spoilers and slats.
So, if we have a COMPLETE ELECTRICAL loss on the A380, we have RAT which supplies Electric to the aircraft and to electrical flight controls.
But if we have a TOTAL FLIGHT COMPUTERS failure ? (PRIMary, and SECondary), how can we control this big bird ? Because I know that the A380 don't have mechanical control, there is a pitch trim switch and not a wheel as the A320, but I thought that this switch is also electrically powered, so we can not use this switch in the case of a complete loss of all flight computers. And for the Rudder ? I think it is also powered from flight computers (P1,S1, P2,S2) for the upper rudder, and (P1 ,S1, P3, S3) for the lower rudder, but moved thanks to Yellow and Green Hydraulic OR Electrically (EHA), but we can't move it due to loss of flight computers right ?
