A320 Alternate Attitude Laws

[RvB]

Hi, probably reposting this question - but can´t find any other hints :
FCOM says that, in "Abnormal Attitudes Laws" there is no reversion to Direct Law once extending the gear.
Does anyone know the backround for this logic and can anyone answer the question what kind of landing handling is to be expected.
IOW, does the plane expect me to be landed in pitch alternate law, thus with load factor demand in pitch ?

[rudderrudderrat]

Hi RvB,
"When the aircraft has recovered from its abnormal attitude, the flight control laws in effect are :
in pitch : alternate law without protection with autotrim.
in roll : full authority direct law with yaw alternate law.
There is no reversion to the direct law when the pilot extends the landing gear."

So it appears there will be no nose down bias applied below 30 radio and you will have to fly the aircraft onto the runway rather than try to hold it off.

Does anyone know the backround for this logic
I guess if the "protections" have failed to prevent the aircraft from exceeding 125° bank, Pitch > 50° nose up or 30° nose down, Angle of attack > 30° or < - 10°, Speed > 440 knots or < 60 knots etc. then it was decided to give the pilot a very simple roll direct and load factor demand in pitch, with no other Law changes.

[RvB]

Hi, thank you very much for your replies so far.
I was relating towards FCOM Flight Controls Law Reconfiguration, between Direct Law and Mechanical Backup.

[DutchOne]

I was relating towards FCOM Flight Controls Law Reconfiguration, between Direct Law and Mechanical Backup

Where in your post were you relating to that? And what will be your precise question if you take those two features into account?

[EGPFlyer]

DutchOne, he was referring to the physical location in the FCOM. Abnormal Attitude Law falls between the Direct Law page and the Mechanical Backup page.

[mcdhu]

Tried it in the sim once.
Landing attitude is achieved with "blips" on the stick returning it to neutral after each input.

[dream747]

Just to revisit this topic out of interest. If anyone has seen the latest FCOM revision from Airbus, the same section now has been revised and the mentioning of no Direct Law on Landing after the activation of abnormal attitude law is introduced has been removed.

So do you we now get Direct Law on landing or not?



Once the abnormal attitude law is activated: ‐ The pitch alternate law is active with no protection, except load–factor protection and without autotrim. ‐ The roll direct law is active ‐ The yaw mechanical law is active. After recovery, the flight control system effects are: ‐ The pitch alternate law is active with no protection and with autotrim. ‐ The roll direct law is active ‐ The yaw alternate law is active.

[vilas]

RRR &MCDHU
After abnormal attitude law if you reset ELAC you can get into direct law with gear down.