A320 SFCC 2 fault

[dream747]

Hi guys,

Why is with SFCC 2 channel failure, we can't land with CONF 3? Or can we?

We dispatched the aircraft with this particular fault, and elected to do a CONF 3 landing and we set it up as per the normal CONF 3 landing procedures in the FMGC & pushed the LDG FLAP 3 on the overhead panel but on finals the landing ECAM memo for landing config 3 remains in blue after Flap 3 has been selected. Why is this so? Couldn't find anything in the manuals.

Thanks!

[mcdhu]

Maybe this is one of those esoteric Airbus things that they don't think you need to know.

Perhaps SFCC 2 signals the ECAM Landing Memo with the flaps/slats position?

I'll try it in the sim over the w/e and get back if anything significant transpires.

Cheers all
mcdhu

[sonicbum]

Hi guys,

Why is with SFCC 2 channel failure, we can't land with CONF 3? Or can we?

We dispatched the aircraft with this particular fault, and elected to do a CONF 3 landing and we set it up as per the normal CONF 3 landing procedures in the FMGC & pushed the LDG FLAP 3 on the overhead panel but on finals the landing ECAM memo for landing config 3 remains in blue after Flap 3 has been selected. Why is this so? Couldn't find anything in the manuals.

Thanks!

Hi,

There is nothing specified in the FCOM/MEL as you say. It is probably due to a glitch. If you dispatch with MEL slat channel 2 then the operational procedure tells you to takeoff with any other configuration other than 1+F because if you loose channel 1 the slats will already be in a landing position, therefore CONF3 is absolutely feasible.

[Goldenrivett]

Hi sonicbum,
operational procedure tells you to takeoff with any other configuration other than 1+F because if you loose channel 1 the slats will already be in a landing position
Does that mean you have to fly all the way to your destination with 1+F in case you loose channel 1?

The reason for not using F+1 for take off is to avoid having premature auto Flap Retraction due single false ADR speed signal.

[vilas]

Goldenrivett
I tend to agree with sonicbum. If You loose channel one surely you do not go to your destination but obviously land back. With slats in 2+3 positions speed increment will be minimum and if required it will be easier on landing distance in overweight landing procedure. As far as your point about false ADR signal is concerned it is not likely to happen as the MEL requires all ADRs to be serviceable.

[sonicbum]

Hi golden,

The probability of your scenario is, imho, lower than losing the other slat channel, or dc ess or blue hyd, any of these and you lose the slats and end up in ALTN LAW too.

[Goldenrivett]

vilas,
With slats in 2+3 positions speed increment will be minimum and if required it will be easier on landing distance in overweight landing procedure.
Why would you want to Land overweight if the second SFCC failed? There is no requirement to LAND ASAP, and surely you would be looking for a suitably long runway somewhere else.

As far as your point about false ADR signal is concerned it is not likely to happen as the MEL requires all ADRs to be serviceable.
See the explanation in MEL with ADR2 inop 34-10-02B.

"FOR TAKEOFF
Takeoff in CONF 1+F is not permitted.
Note:
When the ADR 2 pb-sw is set to OFF, and if the aircraft is in CONF 1+F, the SFCS n°2 Flap channel is unable to crosscheck the airspeed coming from the ADR 1 with the ADR 2 airspeed coming from the SFCS n°2 Slat channel. This may lead to an uncommanded flap retraction during the takeoff. As a consequence, takeoff in CONF 1+F is not permitted when the ADR 2 pb-sw is set to OFF."

Please explain how SFCS No 2 can cross check anything if it is US.

Hi sonicbum,
I don't know what the chances are of any of those you list failing, but the premature retraction of the flaps during the take off phase is considered to be a more serious problem and easily avoided by not permitting 1+F take off.

[sonicbum]

Hi Golden,

Your post makes perfect sense. It is probably the main reason looking at the system as it is described in the MEL.

[vilas]

Goldenrivett
I didn't mean you must but just in case you have to because there was a case in India in below minimum visibility A300B4 went round and had a flap jam. Resulted in a forced landing as they didn't reach the diversion. While ADR2 inop MEL I wasn't aware and is interesting. It is prudent to prevent any possibility because mandating CONF2 take off is no big deal.In that case you are right. But what about the original post why does it show incomplete landing Memo?

[Goldenrivett]

villas,
I don't know of any failure which requires F Full instead of F3.
Only Landing Distance Available dictates F Full over F3.

I suspect finger trouble (GPWS F3 button not pressed).

[Goldenrivett]

Hi EcamSurprise,
Sorry. You are correct.

I should have RTFQ properly.

[sonicbum]

Golden I have checked the same situation for the A330 and there is no restriction on using CONF 1+F in case of dispatch with slat chan 2 inop or ADR 2 although the system architecture appears the same. Any idea or somebody flying both types has any thoughts ?

[Goldenrivett]

Hi Sonicbum,

Sorry, I have no idea about A330.

I found this diagram which shows you only need SFCC 1 to be working for the Flaps 3 / Full + GPWS logic Position. So I can't explain explain the OP's question.

http://www.blackholes.org.uk/PP/SFCC.PNG

[dream747]

Thanks for the replies guys.

Yes we were caught by surprise that it didn't register on the ECAM. Just to be sure, we tried it on both sectors, and the result was the same. We decided to go with CONF FULL and set it up accordingly on both landings, and there we have, no blue on landing ECAM Memo. So it does register for config FULL?

[mcdhu]

Just tried it in a Thales 320 CFM sim.
Entered SFCC Flap and Slat Channel 2 fault, pressed the GPWS Landing Flap 3 button (and also Flap 3 prompt on Perf App Page).
When Flap 3 selected, no blue on ECAM Ldg Memo.
Cheers,
Mcdhu

[dream747]

Interesting, ours was a MSN 5xxx IAE powered A320.

If we had continued the approach with the LDG CONF 3 ECAM Memo still in blue but we visually confirm that flap configuration is in 3 in our case, would the GPWS warning scream at us for being not in landing config on short finals?

[mcdhu]

Not if you had pressed the GPWS Flap Mode OFF.
mcdhu