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-   -   G + B Hydraulic Failure A320 (https://www.pprune.org/tech-log/587770-g-b-hydraulic-failure-a320.html)

EcamSurprise 5th Dec 2016 21:22


Even with slats out, if I did not respect that printed line "L/G dn at 200 kt", I can vividly see many a TRE looking very deeply in my eyes after a session.
Agree.


Plus I am going to fly the approach with the QRH (not the ECAM), approach portion of summaries.
Agree.

Unless you AND your colleague have this pervious knowledge that "if slats out, 200kts GD doesn't apply" then I would imagine you would more think the ECAM is wrong vs the QRH SUMMARY APPCH section.

End of the day, what is the safest, most cautious and most conservative method? I would say applying the 200kts / gear down to maximise controllability even if, perhaps, it is not strictly needed or demanded.

FlightDetent 5th Dec 2016 22:23


then I would imagine you would more think the ECAM is wrong vs the QRH SUMMARY APPCH section.
Well, not me - honestly. I would think "thank you QRH summaries for giving this advice which was not included in STATUS". The whole idea that the instruction is actively missing on STS on purpouse and thus ECAM and QRH are in disagreement would not dawn on me at all.

The next question would be, did Airbus omit the logical split slats/no slats by mistake(*) or for a reason?
* = and are we first to find out just yesterday, with 1000 A/C built? Somehow I do not think so.

EcamSurprise 5th Dec 2016 22:33


Well, not me. I would think "thank you QRH summaries for giving this advice in which was not included in STATUS".
I'm in agreement. My post was meant to come across that if it was missing on the STS but published in the QRH, I would think many would pressure that the QRH is correct and the ECAM either was wrong or didn't state it by default.

vilas 6th Dec 2016 04:58

It is an interesting journey this G+B failure. Starting with configuring all the way to Landing Conf then gear down, then asking to increase speed to 200kts if less and lowering gear before taking any flaps (instructor guide) and finally elimination of any guide lines in FCTM for G+B. Also not mentioning about slats in the SUMMARY. Something about the summaries. They are collection of all the required procedures in one place arranged in flight phases to avoid shuffling QRH pages from procedure to procedure. Summaries do not tell you anything extra but rather abbreviate procedures like slat/flap jam and gravity extension making one wonder why can't these elaborate procedures be short in the first place. They are not mandatory (that's what it said before) but saves time. STATUS review is part of approach briefing so if it mentioned something it is in order to consider that. Otherwise with slats extended you will be closer to S speed and you will have to increase speed to get 200kts. Since it is not required by STATUS why bother?

Mooneyboy 14th Dec 2016 08:21

I know this thread hasn't been active for a bit but just a couple of points to clarify on this.

If you do have 1 stage of slats extended when you get double failure and you decide to fly the approach as per the QRH summary then: You ll roughly be 200kts depending on weight anyway and need to be in manual thrust. Gear down then F2 F3 and decelerate to VAPP. As you have some slat VREF +10 should be bugged as per the status and this relate to just above VLS once fully configured.

In terms of ldg district cal. G+B in QRH relates to no slats on landing and VREF +25. In reality with one stage slat looking at in flight slat/flap performance the ldg dist takes into account the increase in approach speed but not the loss of ground spoilers 5 3 and 1. Surely then your ldg dist is going to be increased over a purely vref +10 ldg distance?

Last if slats were at zero so classic G+B failure from clean would you not config athr off then F1 (I know it doesn't put any slat out but at least SRS avail in G/A mode) 200kts gear down F2 F3 then VAPP.

Any help much appreciated.

vilas 14th Dec 2016 17:03

If you had G+B in clean configuration then yes ATHR off, speed 200 gear down and flaps 1, 2 and 3.

vilas 15th Dec 2016 14:57

Boyington
If you are still around some information for you. All aircrafts do not display that line" If slat retracted". Following aircraft display that line:


Ident.: PRO-ABN-29-J-NG00934
Applicable to: MSN 0138-0148, 0249,0255, 0301, 0384-0400, 0557-0724
Ident.:PRO-ABN-29-J-00011634.0001001 / 16 NOV 11


Ident.: PRO-ABN-29-J-NG00934
Applicable to: MSN 0185, 0241, 0250, 0334-0335,0440-0497, 0758, 0943-1818
dent.:PRO-ABN-29-J-00011634.0001001 / 16 NOV 11


MSN below do not display that line:


Ident.: PRO-ABN-29-J-NG00934
Applicable to: MSN 0199-0240, 0264
Ident.:PRO-ABN-29-J-00011634.0001001 / 16 NOV 11


Ident.:PRO-ABN-29-J-NG00934
Applicable to: MSN 0932
Ident.:PRO-ABN-29-J-00011634.0001001 / 16 NOV 11

Mooneyboy 16th Dec 2016 07:39

Thanks for that villas.

If in the example of having already selected flap 1 for approach and then lose both G+B then as discussed earlier in thread VREF+10 is displayed on the STS. Looking in the expanded FCOM proc for G+B below it only mentions Vref +25. The expanded notes says 'speed must be increased due to loss of spoilers AND ailerons'.

My concern with using the VREF+10 is yes in terms of spoilers you should be fine with this lower speed compared to G+B in clean config however with VREF+10 is this enough to take into account the loss of ailerons? What I wouldn't want to happen is get to the flare and find hardly any roll authority since only splr 2+4 available for roll coupled with the lower VREF+10.

vilas 16th Dec 2016 11:27

Mooneyboy
Your concern is right. I think we were misled by the assumption that with Slat extended delta vref is Vref+10. There is no reason why would it ignore other effects of dual Hyd fail. With slat extended all that changes is you do not have to lower gear at 200kts. but rest of the STATUS remains applicable which says:


APPR SPD..................................................VREF +25 KT


Approach speed must be increased, due to the loss of
ailerons and slats.


LDG DIST PROC...................................................APPLY


and landing distance should be found from Dual Hyd Fail G+B and not from SLAT/FLAP procedure.


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