Airbus 320 Gear/Flap sequence
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Airbus 320 Gear/Flap sequence
Until a few years ago it was standard on Airbus 320 family to call for Gear down, flaps 3" as consecutive actions following each other immideately (similar to the 737's "Gear down flap 15).
Sometime ago the SOPs where written to the effect that one has to wait for the gear's 3 greens to appear before one can call for for further flaps.
Is this just a cosmetic change or is there something technical about it, like load on hydraulics, for example?
Sometime ago the SOPs where written to the effect that one has to wait for the gear's 3 greens to appear before one can call for for further flaps.
Is this just a cosmetic change or is there something technical about it, like load on hydraulics, for example?
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load on green system
I believe thats the reason allright. Load on the Green system. Airbus had some problems with cracks in pumps 7, 8 years ago. I lost the green system 3 times. This was one of the interim "cures" before the pumps were modified. It's seems to have remained as an sop.
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AFAIK there is now no requirement to wait for the gear to be down before selecting the next stage of flaps.
If you think about it, a couple of tonnes of gear going down should not put strain on the pumps because it'll lower itself perfectly well! There are probably 'snubbers' in the hydraulic lines (or the gear itself) to prevent it coming down too quickly. In this situation a more likely scenario would be cavitation due to excess fluid flow.
Any Engineers out there shed more light on this?
If you think about it, a couple of tonnes of gear going down should not put strain on the pumps because it'll lower itself perfectly well! There are probably 'snubbers' in the hydraulic lines (or the gear itself) to prevent it coming down too quickly. In this situation a more likely scenario would be cavitation due to excess fluid flow.
Any Engineers out there shed more light on this?
Last edited by idg; 28th Feb 2007 at 06:25.
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"When landing gear down"
Reference the previous few posts. FCOM 3.3.18.
Intermediate/Final approach,(ILS entered in flight plan)
" When Flaps at 2, Gear Down"
"When Landing Gear Down, Select Flaps 3"
This is from the Airbus manuals aboard our aircraft anyway.
My own input would be that although the Gear itself maybe assisted by gravity on extension, those main gear doors are still quite large and it must be a fair load on the green system to close them.
Food for thought.
Intermediate/Final approach,(ILS entered in flight plan)
" When Flaps at 2, Gear Down"
"When Landing Gear Down, Select Flaps 3"
This is from the Airbus manuals aboard our aircraft anyway.
My own input would be that although the Gear itself maybe assisted by gravity on extension, those main gear doors are still quite large and it must be a fair load on the green system to close them.
Food for thought.
