A320 Green+Yellow fail

[vilas]

Hi everybody
When we loose both green and yellow hydraulics flaps are stuck and slats position is same for 2 and 3. But if you move the flap lever from 2 to 3 the VFE changes to 185KTS from 200 KTS without any movement of flap/slat because VFE is displayed according to lever position. Obviously it is incorrect. Then why does the ECAM/QRH ask you land in lever 3 position. GPWS is put off anyway so that is also not the issue. Thanks

[TwoTone-7]

As far as I know. Flap is moved to F3 position in order to set up the aircraft for land mode and to have relevant go around modes in case of a go around.

[Natstrackalpha]

Yeh, Right on the button.
Plan to land flaps Full even if it is not. QRH. Landing Dist corrections
Also, chances are your Go Around, if any will be doing what? with the gear?

[aanubis]

One doubt ...
Lets say Flaps stucked at postion 2. But we are preparing to land in config 3 or FULL. The Vapp and VFE will be according to lever position i.e 3 or FULL and actual flaps are in position 2. Arent we flying on lower speed for this config (2). ??
Please explain what I'm missing here ...

[vilas]

To get G/A mode all you need is lever 1 position. Read PRO-ABN-27 P7-36. and Natstrackalpha you don,t plan flap full because slat will move to 27 degrees which is against ECAM PROCEDURE. If you go around then no change in configuration. All given in ECAM. This one is not that easy.

[westinghouse]

Maybe for commonality with the g+b hydraulic approach. Otherwise a very good question.

However for the 330 we use flap 2 for the dual hydraulic failures. Why can't flap3 be used ?

[Microburst2002]

GPWS, maybe?

With gpws flap mode off you dont have available its protection for a possible CFIT. If you do your final approach to a mountain instead of a runway, the gpws will not alert until too low gear. WIth GPWS in flap 3, you still have that protection, right?

But in case of flap and slata jammed at zero the precedure is flaps one only, why?

[vilas]

Microburst 2002
You don't get GPWS because of flap lever but actual position of flap. Since flap is stuck ECAM asks you to put it off. otherwise you will keep getting "too low flap". So that is not the reason. This one is a real teaser. In case of slat/flap stuck at 0, I mentioned earlier that you need the lever in 1 position to get the go around mode.

[vilas]

aanubis
Vls does not come from lever position. When you have slat/flap problem it is the only speed that is correct. It is always correct for present configuration. Displayed VFE, VFE next, F, S all are from the lever. They are good time friends.

[Slasher]

Bit off topic but anyone ever had an actual flap lever failure?
A little tricky when it comes to the GA...

[Natstrackalpha]

A320 Green+yellow fail
To get G/A mode all you need is lever 1 position. Read PRO-ABN-27 P7-36. and Natstrackalpha you don,t plan flap full because slat will move to 27 degrees which is against ECAM PROCEDURE. If you go around then no change in configuration. All given in ECAM. This one is not that easy.
Last edited by vilas; 28th May 2012 at 02:40.
Well, yeh, Villa I see what you mean, but what I meant was:The landing is made in Config 3 but the corrections are made to the Flap FULL Vref shown as VLS with Config Full selected on the Perf Approach page. You can enter the corrected speed into the Vapp fields as an aide-memoir. The Vapp is flown using Selected Speed.
*
the required Landing Distance is obtained from the from the landing distance Without Autobrake Config FULL and as I said many moons ago, for runways longer than 2500 meteres landing distance is not normally a limiting consideration.

Do the app as you ould for Landing with Flaps and Slates Jammed - NHP briefs the drill to talk HP though the config and spd changes.

Flaps and Slats will be SLOW and you will have to gravity drop the gear which will knock out the the NWS, this will also be the case even if you have a bit of Green hyd sill operational . - also, you are now CAT 1.

Don`t forget you have a frozen stab, so no trim. On initial app you may not notice.
the stab while you are in Alternate Law, but when you lower the gear you will go into Direct Law and your trim will be set at the speed you were at when you dropped the gear. It is for that reason .you should select Flaps 3. reduce speed to Vapp and then extend the gear. The landing ATT may be unusual, continue to monitor the PFD until you get used to the new att. REV 1 and/or 2 will be inop NWS is inop but you may have a bit of anti-skid and maybe some form of auto-brake, you could possibly vacate prior to shutdown.

[vilas]

Natstrackalpha
All that long procedure I am fully aware off. I teach every other day.You still haven't understood my question. When you move the lever to position3, nothing moves because flaps are stuck at zero and slats positon for 2&3 is same. Then why go to 3? You can still reduce to Vapp. Lever does not produce the lift required, the surface when it moves it does. And from where do you think A/Brake and anti skid will come? It doesn't. you only have 7 applications of brake, and you restrict brake pressure to 1000psi. with new ABCU it restricts to 1000 automatically.

[Microburst2002]

Vilas

Why is there GPWS FLAP MODE OFF in the blue remaining and GPWS LDG FLAP 3 ON in the yellow remaining?

Both are FOR LANDING USE FLAPS 3' Though...

You know... You raised a very good question!

[Microburst2002]

Vilas

In the EGPWC schematic In the FCOM there are only two possible inputs from the SFCC:
FULL or CONF3

If it was actual, any abnormal configuration would inevitably lead to a GPWS during short final unless FLAP MODE OFF. But we see that in yellow remaining we push FLAP 3 mode ON. So I would say, without betting my savings, that GPWS mode 4 is governed by flap lever position rather than actual flaps/slats.

Still, blue remaining procedure calls for landing conf 3, but GPWS will be OFF, so I don't understand the reason for the conf 3 when in many cases nothing at all happens when moving the lever to 3. Moreover, by doing so displayed VFE is more in error than with the lever at 2.

Maybe a simulator experiment can give a clue on the reason, if you have the chance...

[vilas]

microburst
With yellow remaining flaps move so you can select flap3 on the GPWS and have its protection and land with flap3. But with blue remaining flaps do not move so you will get "too low flaps" if you select flap3 therefore ECAM tells you to put the mode OFF. So far it is straight forward. But why select 3 when nothing is going to move that is my question also.

[Microburst2002]

Yep, u right, now I can see the GPWS mode 4 logic is based specifically in the flaps, not in the configuration as a whole. The schematic should say flaps instead of conf. The flaps fault ECAM clarified this to me.

Good I didint bet anything!

[Airmann]

Villa: without looking at any technical manuals, there are two things that.i can think of off the top of my head.

1. The simple answer would be tha airbus want you to do this just to maintain reletavily normal operating procedure.

2. In the event of a go around airbus might not want pilots inadvertently raising the slats into the Config 1 position due to the potential of stalling at low speeds, the lift is already already compromised by the lack of flaps, so keeping the flaps lever at Config 3 ensures that an error cannot be made.

Just some thoughts.

[vilas]

Well that is good thinking. Nothing in any of the published material so far.

[Natstrackalpha]

Natstrackalpha
All that long procedure I am fully aware off. I teach every other day.You still haven't understood my question. When you move the lever to position3, nothing moves because flaps are stuck at zero and slats positon for 2&3 is same. Then why go to 3? You can still reduce to Vapp. Lever does not produce the lift required, the surface when it moves it does. And from where do you think A/Brake and anti skid will come? It doesn't. you only have 7 applications of brake, and you restrict brake pressure to 1000psi. with new ABCU it restricts to 1000 automatically.

Maybe the FAC will expect a different ATT in config 3 than in config Full-

[Rocket3837]

Hello all,

For g+y inop:
landing is made with flaps handle at 3 although salts do not move from pos 2 to 3 for commonality reasons. If U notice that all F/CTL failures require flaps handle at 3. And that was Airbus official answer to my company years ago.

[vilas]

Rocket3837
I do not see any other logic in it. However it does change the VFE incorrectly and the QRH adds to the cofusion by saying at the bottom of the Landing with slat or flap jammed CL
"in some cases MAX SPEED-10 may be a few knots higher than the VFE. In this situation, pilots may follow the VFE". I cannot see why will this happen.

[hetfield]

BTW it happened, again....


Incident: Air Canada A319 near Winnipeg on May 30th 2012, two hydraulic systems failed after leak (http://avherald.com/h?article=4506b0eb&opt=0)

[Boyington]

Could it be because, in case the system is recoverable in case of Low Pressure or Overheat and the condition disappears later and we recover the system we can get the surfaces moving?

[vilas]

I received a reply from airbus that they have stated at the time of certification that all abnormal landings will be in flap3. So to confirm to that in G+Y fail the lever is moved to 3 even though the nothing moves.

[EGKK.]

Very nice topic!

As a few people have stated correctly the Egpws system uses actual flap (not slat) position to determine whether it is configured for landing. So in the case of Blue HYD Remaining the procedure calls for EGPWS flap mode off to not get a nuisance warning on landing.

Making an approach with flap lever in position 2 or 3 will not make any difference to the slats actual position for landing BUT it does make a huge impact for the Go around...the approach is already being flown very close to VLS but now we must consider in the event of a Go Around the Gear now remains down (gravity extension), no use of the Stab trim available as this is powered by Green and Yellow HYD systems (so now a positive force must remain on the side stick to follow the correct pitch attitude safely as we are in DIRECT law) and also remember we have zero protections now also. VLS and VSW are very close on this kind of approach. Basic aerodynamics to conclude this really nice topic...Making an approach in config 2 then innitainating a go around and moving the flap lever up one stage in this condition would not be a wise idea as this has a good possibility of a stall.

Hope that is fairly clear and am happy to concede defeat on any of what I have stated above.

[vilas]

Making an approach in config 2 then innitainating a go around and moving the flap lever up one stage in this condition would not be a wise idea as this has a good possibility of a stall EGKK you are wrong on both counts. First Stalling speed is not dependant on flap lever but actual surface position which in this case remains at 2. Secondly incase of a GA you do not retract flap one step with double hydraulic fail but maintain the conf.

[wiedehopf]

he never said the stall speed was lower dependant on the lever.

and maybe you don't put the flaps up when doing this landing BUT it can still be a precaution by airbus for the case a pilot puts the flaps up 1 notch.

[EGKK.]

Hi Vilas

You are right (Kind of...) No where does it specifically specify you are to remain in the selected lever position during a Go around, although it does state if a circuit is planned then to leave it there. I'm pretty sure if Airbus had concerns they would make this in bold capitals but it tell us to clean up if a diversion is planned and I'm pretty confident having the lever in Flap 3 will keep us safe if we retract a stage of flap. In addition to a slat only approach our pitch attitude is already high compared to a normal Slat/Flap approach and pilots may have a tendency to raise the nose by the same amount as they normally would then if we factor in a stage of slat being removed if we were to make an approach in flap lever 2 then retracting a stage during a Go around...well you get my point.

But as mentioned above i did not state that Vls is dependent on lever but actual aircraft config. So in our case 2 stages of Slat only. If we were to retract a stage through force of habit from flap position 2 to 1 then we would change the actual config and would be in a possible sticky situation. If you get time Google 'Confirmation bias' it's very interesting what we as humans do in situations even when told what to expect.

Airbus is by no means perfect, and they know this! This procedure is a result of sensible thinking by the people who have designed this aircraft and seen the pitt falls through thousands of hours of simulated malfunctions and issues that have probably helped mould this procedure the way it is written today.

A good example of this is in the Green and Blue Dual Hyd failure were the procedure asks us to select manual thrust at around 200Kts...This is because the aircraft is in an aerodynamic mess (partial use of only half the elevator no aileron and 2 roll spoilers per wing to be used for banking) The designers were wise enough see that with the extension of the gear putting the aircraft into direct Law and flying at the approach speed (which again would be close to Vls and VSW) the aircraft MAY not cope well, hence the extension at 200kts and with manual thrust (they do not trust their own equipment in this particular circumstance) Could we leave the Auto thrust in...Yes. Would we crash...probably not. Is it wise...I would say no.

Could we fly and approach (G and Y Dual Failure) in flap lever 2...Yes but once again probably not wise.

[vilas]

EGKK
You didn't write clearly what you explained now. However I am the one who started this thread five years back to get an answer and all these thoughts went through my mind. So later I asked the airbus about it also stating that unnecessarily moving the flap lever to 3 causes the VFE to be displayed incorrectly. They did not give the reason of safer GA in three. I will reproduce a small part of it below.
I agree with you that selection CONF 2 during approach, and maintaining CONF 2 for Go-Around could have been less misleading for the pilot. But the rationale of selecting CONF 3 for A320 family aircraft is historical, as this configuration has been proved, in terms of certification, as being the optimum one in terms of handling qualities in alternate law.
Perhaps Airbus themselves had noticed it because in A330 they had changed it. If you see the same failure in A330 QRH it tells you to land in flap2.
Also flap retraction of one step in all cases is not required and this was discussed sometime back. You can search for it. Retraction of one step in GA is due to high drag in flaps full. Conf1, 2, and three are take off configs and do not mandatorily require retraction especially in 1 and 2. There is also airbus discussion on this.

[vilas]

EGKK
No where does it specifically specify you are to remain in the selected lever position during a Go around, Really? It gets very interesting when it comes to retracting flaps(slats actually). The QRH says for diversion if flaps jammed at zero select clean configuration. Maintain speed close to Vapp(Due to pitch trim unusable). The problem is F and S speeds are false and they will take you for a ride. How and when do you retract the slats? Airbus doesn't tell you what to do If you get time Google 'Confirmation bias' it's very interesting what we as humans do in situations even when told what to expect. Never do anything out of bias.
For 60T the Vref is 130+25 the Vapp is 155kts. You cannot retract at that speed. You need to increase the speed close to 195 before retracting and once in clean you cannot come back to 155kts. You have to fly out of trim to save your life. What QRH says is poppy cock. All this needs to be thought of and briefed before the approach begins. So diversion is virtually out of question. Do your FORDEC carefully. May be another few approaches but diversion? No way!

[Rocket3837]

For commonality reasons.
All landings in Direct Law require flaps 3....