Airbus flight law indication and selection
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Join Date: Sep 2007
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Airbus flight law indication and selection
Do Airbus FBW aircraft give some sort of continuous indication on the instrument panel of the flight law currently in effect (normal, alternate, etc.)? If not, how do you know which law applies?
Also, is there a way for the pilot to force a specific flight law to be used? Is there a button he can push to force direct law, for example?
Also, is there a way for the pilot to force a specific flight law to be used? Is there a button he can push to force direct law, for example?
When normal law is in effect you get no specific indication but you can see on the PFD that the envelope limits are active. Alternate law is indicated as a memo item and depending on which alternate law the envelope limits can be seen as inactive on the PFD. You can switch off the flight control computers on the overhead panel but you cannot force direct law that way AFAIK. It will get you into alternate or mechanical reversion.
Someone who knows more than me will surely correct this.
Someone who knows more than me will surely correct this.
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No specific mode indicated when all is normal - the crews only want to be advised or warned of abnormal conditions. Alternate law is indicated by name and will be shown with the failures causing it on the ECAM. Only come across this once with a Post Flight Report showing multiple failures due the cascade effect of the initial snag (Dual ADIRU fail). Not seen Direct Law on one though the first thing I'd change would be the seat covers in the flight deck.......
Right, I'll get me coat...
Right, I'll get me coat...
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I guess you are misunderstanding Direct Law and Mechanical Backup
Direct Law : Normal system operating. No indication
Alt Law : Degraded operation. You lose some protections (roll, overspeed, etc.) You've got an ECAM caution and a status remind. You can force it by turning off the two Flight Augmentation Computers (FAC's).
Direct Law : You are in a cessna. You are operating directly to the controls, without protections. You lose autotrim. I think you can force it by turning off some computers, or by lowering the gear when in alternate law.
Mechanical Backup : You lose all computers and you can control the aircraft by the pitch trim wheel (for pitch) and by the rudders (for yaw). No direct control on the ailerons. USE MAN PITCH TRIM indication on PFD
This situation is expected as an intermediate situation, the time to get back some computers to revert to direct or alternate law. But some guys tried ans succeeded to land the aircraft in this situation in the sim.
There is too the A300 in baghdad which was in a quasi similar situation, and they successfully landed.
Some instructors practice this exercice in lights aircrafts (cessna, robin) with controling only with thrust, pitch trim and rudder.
Direct Law : Normal system operating. No indication
Alt Law : Degraded operation. You lose some protections (roll, overspeed, etc.) You've got an ECAM caution and a status remind. You can force it by turning off the two Flight Augmentation Computers (FAC's).
Direct Law : You are in a cessna. You are operating directly to the controls, without protections. You lose autotrim. I think you can force it by turning off some computers, or by lowering the gear when in alternate law.
Mechanical Backup : You lose all computers and you can control the aircraft by the pitch trim wheel (for pitch) and by the rudders (for yaw). No direct control on the ailerons. USE MAN PITCH TRIM indication on PFD
This situation is expected as an intermediate situation, the time to get back some computers to revert to direct or alternate law. But some guys tried ans succeeded to land the aircraft in this situation in the sim.
There is too the A300 in baghdad which was in a quasi similar situation, and they successfully landed.
Some instructors practice this exercice in lights aircrafts (cessna, robin) with controling only with thrust, pitch trim and rudder.
Normal Law: Green = signs on PFD signifying manoeuvre limits
Alternate Law: signs replaced by ambers X's
Direct Law: amber X's with "USE MAN PITCH TRIM" in amber above artificial horizon.
Mech Backup: "MAN PITCH TRIM ONLY" in red above horizon.
(AIRBUS A320 series)
Alternate Law: signs replaced by ambers X's
Direct Law: amber X's with "USE MAN PITCH TRIM" in amber above artificial horizon.
Mech Backup: "MAN PITCH TRIM ONLY" in red above horizon.
(AIRBUS A320 series)
