A320 EMERGENCY LAND ALL ENG FAILURE checklist
 

Hello,

Regarding the EMERGENCY LAND ALL ENG FAILURE checklist found in PRO-ABN-MISC section of FCOM:
Does anybody have any idea as to why there is a WEIGHT/VAPP table?
Since FMGC1 should always be available even in case of Emer. elec. gen config (VLS/VAPP obtained from ZFW entry in MCDU), that table should not be needed? is it in case of MCDU failure?
The table is absent in the forced landing and ditching checklists so it makes me wonder how necessary they are.
Thanks in advance

That procedure is used after the loss of thrust near the ground (Sullenberger scenario) and it is recommended to use FLAP 2. (No VAPP in FMGC for F2)
The Forced Landing & Ditching checklist asks for Maximum Avail Flap (F3 or Full).

Thank you very much for the reply.

I think it also takes into account the loss of flaps hence the higher VAPP figure. So you will get flaps 2 (slats only)

EMER LANDING ALL ENG FAIL and FORCED LANDING are two separate procedures. If you're doing a forced landing on a non standard airfield or a strip with engines available like due to smoke, fire etc. obviously you should land with Max flaps available to get minimum Vapp. That is available in the MCDU and as VLS on the PFD. But things are different when you forced land due to Double Engine Flame out. Double Engine Flame Out also puts you in dual hydraulic fail G+Y and EMER ELEC Config. That leaves you with flaps jammed. There is no great virtue in landing in Flap2 but since flaps are jammed, slat 2 is the optimum position that can be used. Slat 2&3 is same and slat full will further aggravate the already high attitude. Also no abnormal landings are done in Flap Full. FMGC1 is available but the MCDU approach speed is incorrect and will need amendment. So readymade approach speed is provided which is higher by appx. 20kts than the normal Flap2 speed. That's why the approach speed table is given. However in case of dual engine flame out if you manage to start the APU you will get out of EMER ELEC. In that case you can put the Yellow Elec pump on to get flaps and it is possible to do approach in flaps3. That will lower the approach speed and also landing distance which may be helpful if landing with insufficient field length. But the procedure doesn't mention that.

I just realized I never thanked you for the reply.

Not a must but nice of you.

while we're here, if im on a 6 mile final and loose both engines, will the gear come up while I head for the river ?

The aircraft will be in G+Y fail. The gear may come up before No1 N1 drops to windmilling. If it doesn't you can't Head for the river with gear down.

In the sim, if the failure inserted is merely a dual flameout (no damage) the windmilling engines provide sufficient hydraulic power to extend the flaps, at least part of the way. I'm not sure how accurately this replicates what would happen in the real aircraft.

At approach speed windmilling is not sufficient to lower flaps. Slats come from Blue hydraulic. Gear won't come up.

Fly gross weight (in metric tons) + 75 as Vapp.
Will always work.

As it is Vapp with dual engine flame out is with flap2 and that's also higher by appx 20kts. Must check next time in the Simulator.

Well GW+65 is Vls conf full, add whatever you require according the actual configuration.
GW+75 would be Vls+10 as required be many abnormals. If you're slats only it be GW+90.