A320 Flap Cong on MCDU in Emergency

[yaverona]

Dear Sirs,

In my company during emergency operation; if procedures required to land with flap confg 3, we do not select confg 3 on the mcdu. Only, we sellect for normal operation, if we would like to land confg 3.

My question is;

In the vol3 sop section page 3.03.16 p: 2, there is an explanation like this;

The Ecam may required to land in cong 3, in case of system failure,

* first read vls valu on perf page with full flap and find approach speed.

* then select confg 3 on perf page (mcdu)

Normaly we were finding vapp speed according full flap vls and made a correction for vapp on mcdu. And we do not select confg 3 on mcdu, in case of emergancy.

I would like to learn other companies, procedures about this subject.

[Busdrvr]

When performing a flaps 3, single engine approach we select the EO clear and the config 3, both.

[yaverona]

Dear Busdrvr

I can see why to set confg 3 accoring 3.03.16 p: 2. But your reply brings me another question.

It is the first time I see that a company clear EO prompt, in sigle engine case. Do you know why?

Best Regards

[Hand Solo]

Our SOP is not to touch the EO Clear prompt in the event of an engine failure.

In the case of a Conf 3 landing we leave Conf Full selected on the MCDU. I'm not sure of the logic behind that, but it may be to provide consistency in situations where you are landing with an abnormal flap setting, eg with flaps jammed, where you would normally keep the Conf Full Vapp.

[idg]

The reason for selecting conf3 in the MCDU is one of approach speed.

If the MCDU is left at Conf Full the speed that will be used during approach is F speed. Normally this is of no consequence if there are increments to be added to VLS as the managed speed will then be above F speed anyway.

However if the a/c is light and there is no ( or a small ) increment to VLS then the a/c will fly at F speed and not Vapp as it should.

To fix this the FCOM now calls for F3 to be selected in the MCDU to tell the system that we are going to fly the approach at flap3 and thus reduce to Vapp when F3 is selected. This also gives us the benefit of having GS mini active during the approach.

This all gets a little confusing however when you realise that we will mostly be flying selected speed for approaches during flap/slat malfunctions where the majority of the F3 abnormals occur! FCOM 3.2.10 p7 and QRH 2.32 refer.

[maxalt]

This is getting interesting! Clear the EO prompt with engine fail?? Surely a bad move? Won't you lose all single engine predictions?

Maybe you can explain the logic...I'm very curious!

[mcdhu]

Maxalt, I'm with you on this. I think that the only time you would use the EO Clear prompt was if the FMGC had spuriously detected the EO condition (its criteria for doing so are in the FCOM Vol 4 which we are not given).

Furthermore, if my memory serves me correctly, the early software standards did not include EO predictions so you had to clear it to get any (if a little dodgy) predictions. FMS2 includes EO predictions.

Hope this helps and does not confuse!
Cheers,
mcdhu

[Busdrvr]

Oddly enough it doesn't make much sense to me either, why we select EO clear while single engine. It was explained that the software does not perform correctly ???.....
It doesn't seem like a very plausable explanation. I think it goes back to the days when the Airbus started operation in the US. The FAA was very reluctant to approve anything new and different and placed a lot of restrictions on the operation of the AC. Over the years most things have been resolved, but I think this is one of those thing that slipped through the cracks.

[Iceman49]

The only time we used the EO clr was if we had to do an Approach Nav approach. I thought it allowed you to hook up the autopilot...its been a while.

[Dream Land]

My 2 cents, first of all, if you lose an engine enroute your FM will indicate the altitude the aircraft can maintain on the prog page, also, engine failure at V1, until thrust reduction altitude, the EO function will reduce bank angles. I get rid of EO clear after engine clean up so I get normal managed speeds, any thoughts by bus drivers appreciated.

My SOP dictates we use the flap 3 switch only when flaps 3 are selected due to windshear / gust factor 10 knots above the steady state, or proficiency, all emergency procedures ie direct law approach, you must NOT select CONFIG 3 because any adjustment to Vref should be made, reference to Vls for flaps full, the only way for the FMGC to know this is to be in CONFIG FULL.


DL;)

edited for sp

[idg]

DL,
Yes I agree that one must do Vapp speed additions to ConfFull Vls but then select F3 on MCDU and GPWS panel if Abnormals list calls for landing in F3.

Clearing EO on the MCDU will not, as I understand it, give you back normal bank angle.

FCOM 4.04.30 p10 says:

"Note: The engine out bank angle limits apply, when FG part of the FMGS has detected an engine out. It cannot be cleared by the crew through the E.O. CLEAR prompt."

Clearing the EO will restore predictions but one has to be careful not to use the fuel predictions as these will be completely wrong. Time predictions will be correct however. I think that managed speeds will still be available with prompt still showing.

As far as I can see Pegasus will not give one engine predictions with and engine out.

[Jetset320]

At our last refresher course we had confusion about this point, as pilots recently trained in Toulouse by Airbus instructors were told to select Flaps 3 on MCDU, whilst our SOPs clearly still instruct not to do so.

As previously stated, reason is that increment due to failure is to be added to Vls Conf Full and not Conf 3. Once the new speed is inserted (i.e. overwritten) as the new Vapp, then what difference does it make which Flap setting is selected on MCDU?

Somebody referred to G/S mini being available if Flap 3 is selected. I've heard this before. Isn't G/S mini always available when in managed mode, irrelevent if you have selected a speed in the MCDU (not FCU),or not?

[moleslayer]

If you don't select 'Flap3' on the perf page, the FMGC is still waiting for you to physically set the flaps to FULL, and will therefore only fly to 'F speed',NOT Vapp.
GS mini is only available when the target managed speed is Vapp.


Moley.

[idg]

Moley and RZ,

Moley you are correct about the F3 statement, but actually RZ is correct when he talks of G/S min being available. In fact it is always available and active when an approach is activated.

We see this when flying the a/c on approach when typhoons are around!

The point, in this context, is that when the aircraft is light the Vapp (including any increment) could be less than F speed and thus the aircraft would not be allowed to fly at the correct Vapp.

[mcdhu]

Maybe we are getting to the stage here where we can't see the woods for the trees!

The FCOM now clearly states that if landing conf 3, then press the little button on the mcdu - even if only for consistency!

If Vapp has to be modified, then simply add the increment onto Vls config full which is available from the QRH which you will have out anyway at that stage.

Comments gratefully received.
Cheers,
mcdhu

[Jetset320]

That is exactly the point we are discussing.......our FCOM (still) specifically states NOT to select Faps 3 on the MCDU. And I believe this was in all FCOMs until Airbus changed it recently.

[mcdhu]

I understand what you are saying and indeed you are right in that the Airbus FCOM was recently changed to the current procedure whereby you select the Conf 3 prompt (3.03.16 P2 refers).

But are you saying that your own Airline's SOPs go against this and therefore modify the Airbus FCOM?

Cheers,
mcdhu

[Jetset320]

Precisely. Airbus SOPs are only guidelines and not instructions. Each company formulates it's own, generally mirroring the manufacturer's but adding it's own fleet-wide practices along the way also. Infact my reference is 3.03.16 Pg4 and not Pg 2 (as is yours) and was revised in July 2003, Rev 36.

It clearly states:
<<<Flaps 3 is required in certain abnormal (system failure) situations. In this case the flight crew shall NOT select Conf 3 on the PERF APP page, in order to keep the VLS CONF FULL value displayed on the MCDU.>>>

Whether the change (absence of) was an oversight of my company (and others in this very thread), or else it prefers the old reasoning I don't exactly know.

[idg]

This is cut and pasted from my e-fcom 3.03.16 p2 rev 36
Note that rev 37 is published and will be available soon!

Check or modify the landing configuration. Always select the landing configuration on the PERF APP page :

The pilot may choose FLAP 3 rather than FLAP FULL for landing, depending on the available runway length and go-around performance, or if windshear/severe turbulence is considered possible on the approach.


The ECAM may require landing in configuration 3, in case of a system failure :

First read the VLS CONF FULL value on the PERF APP page to determine the VAPP (or use QRH 2.31).

Then, select CONF 3 on the PERF APP page.


As a general rule, managed speed can be used if the landing configuration and the configuration selected on the PERF APP page are the same. (If they are not the same, the managed speed will not drop down to the approach speed).


Check VAPP according to the FLAPS FULL or FLAPS 3 selection on the MCDU.

The pilot can modify VAPP. The new value will be taken into account for ground speed mini-function.


Note : If some abnormality requires a speed increment for the approach, the increment must be added to VLS CONF FULL