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-   -   Airbus ALTN LAW - FOR LDG USE FLAP 3 (https://www.pprune.org/tech-log/262802-airbus-altn-law-ldg-use-flap-3-a.html)

Right Way Up 6th February 2007 09:46

Can someone give me a reference to "flare mode" of altn law? I have never seen this teminology used on the minibus. My understanding is that with gear down in altn law the logic changes to good old "direct law". (Unless you have had an abnormal attitude but that would be another thread):zzz: :zzz:

Wingswinger 6th February 2007 10:12

FCOM 1.27.30. Alternate Law. Diagram on pitch control.

Right Way Up 6th February 2007 10:42

Thanks for the reference wingswinger. Thats probably why I dislike the FCOM on computer, very easy to miss some of these diagrams.

Clandestino 6th February 2007 13:31


Clandestiono: the sidestick is not directly connected by cables to the ailerons, so has it not occurred to you that the ELACS still control the ailerons and you may not have full knowledge of how the ELACS have been programmed or how the stick deflection/aileron displacement ratio is altered by Flap Lever position.
:O Indeed I´ve posted it wrongly: in direct law there´s switch in ELAC bias as slats extend from zero, but that´s as much as my FCOM would let me know. Did you get your data from maintenance manual?

FlightDetent 6th February 2007 15:23

Older thread here.

FD
(the un-real)

bobrun 7th February 2007 08:49

FlapsOne,
If you are correct, then my manual will have to be amended......here's the quote (straight from the book) regarding a dual RA failure (A330/A340):

(...) mode switching is as follows:
· At take-off, normal law becomes active when the MLG is no longer
compressed and pitch attitude becomes greater than 8°.
· On approach, the flare law becomes active in manual flight when the L/G is extended. If the AP is engaged when the L/G is extended, flare law becomes active at AP disconnect. As and when flare law activates, manual pitch trim is required and “USE MAN PITCH TRIM” is displayed on the PFD.
(...)
:hmm:

FlapsOne 7th February 2007 13:56

Maybe it's different for the 320 series 'cos I cannot find that.

As I have always understood it (since TLS) is that, without RA data, the system cannot give flare mode (the trim adjustment to give flare 'feel') and thus the only course of action is to give DCT LAW (where we all learnt to fly!).


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