320 double hyd failure
 

1. What is the reason in case of B+Y for gravity extension
2. Should we limit crosswind to 15 knots for limitation reason due to 3 spoiers inoperative, and in case G+Y what is the reason to show landing distance in summary on wet&cont RW if it is prohibited
3. In case of G+B why should we do LG extension at 200 knots and how to do it if simult. we should extend flaps 2 passing Vfe 200 knots

Spasibo

To preserve the Green Hydraulic System integrity (FCOM 3.02.29).

Both slats and flaps are now being supplied by the GREEN System, the extra (Enormous) hydraulic load from operating the gear would not be prudent with BLUE and YELLOW out.

Please clarify this question. I understand from what you wrote, that you are asking about a 15 kt limit, and a prohibition on "Wet" regarding G+Y, to which I am not aware of any restriction (QRH).


For improved controllability on a single elevator (FCOM 3.2.29)

Simulate? That's what SIMULATORS are for.

About 15 knots limitation

FCOM 3.01.20 p.3 note 1. In case of double hyd failure we have this case. So I need just confirmation that we have 15 kts crosswind max.
Note 2 limits G+Y to 10 knots & only dru RW. But in QRH summary we have LD table for wet, cont. What is the sense to publish if it is prohibited to land on.

G+B 200 knots

Simult stood for not simulator but for simultanious. We have to extend gears exactly at 200. But at the same time we have to extend flaps 2 passing 200. So what is the right order - flaps, gears or gears, flaps

Correct.
Don't think this is the reason - this is more to do with isolating the landing gear hydraulics in case there is an unknown leak downstream of the Safety Valve and Cut Off Valve. Using Gravity extension isolates the gear hydraulics.

Flap selection is done at VFE NEXT - 5KT. Which means Flap 2 at 195 kt. Gravity Gear extension then flaps.

My copy of does not have any crosswind notes - perhaps this is airline specific? I am not aware of any Airbus wet runway prohibition - and in any case if the only suitable runway is wet/contaminated you have to use it, so the information is necessary. Better to land on a wet runway than fly for an hour on only one hydraulic system.

So first, you are assuming that failure occured with slats=0.
Because, if slats>0, you could not read that on Status page.

If slats=0: you prioritize: what do you need most then? Controllability.
First L/G, then as you are decelerating through VFE, ask for Flaps 2.
There is no need to rush and to do it "simultaneously".

As for your 15 kt X-wind limitation, I don't have any mention of this.
As said, most probably airline ops specifics.

Hello,

Just trying to understand this "Controllability" issue with B+G failure.
FCOM 3.02.29 staes" Extend landing gear at 200kts, to improve contollability when on a single elevator"
My question is :
1. You are on a single elevator even with B+Y failure.what about contollabilty then?Isn't it an issue there or has it to do with failure of other control surfaces also?
2. By taking gear down at 200kts you are actually going into direct law with aircraft clean (as slats are lost and flaps will come out only when selcted to flaps 2).Isn't it a rather an unusual selection because normally we have some amount of flap/slats before taking gear down.
3. In sim sessions we invariably get a stall warning during this phase with upper and lower barber poles momentarily coming together. Is there any way this can be avoided?
Thanks

320p
1. Perhaps the lack of slats affects the airflow over the elevator - the higher than usual speed compensates.
2. Yes it is unusual but that's what the book says! Presumably Airbus tried it the "normal" way and did not like it...
3. A lot depends on the a/c weight, and the pilot's handling skills in Direct Law - I would guess it is a dynamic stall warning, unless you are allowing the a/c to decelerate rapidly once the gear is down. Best to stabilise the speed not below VFE NEXT - 5KT until the flap has reached 2, then decelerate to take Flap 3.
And the stall warning is only doing it's job - I would only worry if you stalled the a/c!

hm, Vfe next -5 is the published procedure. It helps to do config changes in level flight only - it flies like !!!! anyways. Once the gear is down you have a conventional aircraft and two pilots are installed to fly it.

It was free time today to read technical papers onboard:}

So I found an answer in AFM for 200 knots gear extension. It is written in AFM more precisely than in FCOM that we should extend gears at speed less than 200, not strictly at 200. But the purpose for this is the same - improved conrollability. So flaps 2, than gears when convinient. And flaps - passing 200, not at 195, which is just target. And it is better to avoid stall.

What about 15 knots limit for 3 spoilers inop and dry RW for G+Y - thanks to all, so it is our company limitation.

It's an airbus not a space shuttle :E. Don't be so focused on the speed scale...! (as long as you're above Vls )
You're not expected to operate it at + or - 1 knot.