Direct law when landing gear extended a320
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Direct law when landing gear extended a320
Quick question on the a320. When in alternate law, why does the a320 switch to direct law upon extension of the landing gear?
Join Date: Jul 2007
Location: Germany
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All to do with Alternate law not having a flare mode.
The Bus in normal law gains out direct law on T/O and gains in Direct law on landing. This is to ensure the pilot has the appropriate "feel" for landing and takeoff, as having normal law in at landing would feel "odd".
The Alternate law doesn't have this feature, so in order to give the correct "feel" for landing, particularly during the landing flare, its necessary to transition to Direct at some stage. Airbus decided that the best place for this was upon selection of gear down (should be stabilised on approach or hitting top of drop on the ILS typically). It also means you get the more limited protections of alternate law on the go around, as soon as the gear is lifted up and the attitude is transitioning to, or at, G/A climb attitude.
I drive a Boeing, but from previous test pilot selection, this is what I remember of this feature of the Airbus FBW system.
The Bus in normal law gains out direct law on T/O and gains in Direct law on landing. This is to ensure the pilot has the appropriate "feel" for landing and takeoff, as having normal law in at landing would feel "odd".
The Alternate law doesn't have this feature, so in order to give the correct "feel" for landing, particularly during the landing flare, its necessary to transition to Direct at some stage. Airbus decided that the best place for this was upon selection of gear down (should be stabilised on approach or hitting top of drop on the ILS typically). It also means you get the more limited protections of alternate law on the go around, as soon as the gear is lifted up and the attitude is transitioning to, or at, G/A climb attitude.
I drive a Boeing, but from previous test pilot selection, this is what I remember of this feature of the Airbus FBW system.
