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-   -   SRS mode during windshear - A320 (https://www.pprune.org/tech-log/508730-srs-mode-during-windshear-a320.html)

Airmann 27th Feb 2013 08:46

I like I said before, I'm not a big fan of the push-to-level-off before engine is secure, you add unnecessary workload onto both pilots and for no good reason. My company does it but I don't agree with it, I would simply like someone to explain what the benefits are because I see none.

Regarding US Airways, yes they have many of their own procedures some of which you can find online. Airbusdriver.net Gives you an insight into their ideas of how the A320 should be flown.

woodja51 27th Feb 2013 08:51

Engine secure
 
i was told this was Generally defined as when " ENG XX SHUTdown" ...Like before you start APU s, fiddle with TCAS etc, Relight consider erc...
Then alt hold / vs speed zero ( 330/320) and clean up... Once engine out turn is complete also normally for most operators...

Also, chrono is irrelevant for TOGA thrust I think.. Just gives pilot something to do on takeoff.... FADEC monitors it and produces an ecam..."TAke off thrust limit exceeded" or similar....?

Well. On R/R anyway...?

And most FMS have a default altitude of 1500 in them from factories.Northrop/ grumman or honeywell..... So any less is company requested mod...

Boeing generally recommend not below 800 feet...( yes I knowmwe discussing AB) This was partly due to accel segments on SIDs..Being 800' ...now removed mostly I think...

And the fact that if you clean up on one engine below 800'feet you get annoyed by the " dont think dont think (sink) GPWS warning due to low rate of climb ...
Any other opinions or corrections to what I have printed , happy to stand corrected...

vilas 27th Feb 2013 12:16

Chrono is started so that you don'exceed time limit for TOGA, not thrust limit and ECAM has no warning for that. EGPWS warning after takeoff comes not with low rate of climb but decsent.

Flappo 28th Feb 2013 09:22

TOGA if required . AFAIK the bus is FLX single engine certified, in any case you just need to move the thrust levers from FLX to TOGA and move back to MCT, right?

Natstrackalpha 1st Mar 2013 08:44


If a/p is on pull heading! You wouldn't want to be turning before out of shear! That's crazy!
Thats right!--------------(unless there is a rock in the way)

vilas 10th Mar 2013 07:25

Hi guys
There was never any doubt about using TOGA and following SRS if available. But the scenario was we were in TOGA from take off. So when you reach 400ft i.e.( THR RED/ACC ALT) LVRCLB will flash also SRS changes to CLB. We ignore LVRCLB and keep the thrust levers in TOGA. We are in TOGA but FDs are not in SRS. in that context I had suggested if you are following the FDs, pulling speed to prevent pitch down to accelerate. It was not my intention to contradict SOPs. Now we have two options either move thrust levers out of TOGA(do not have to go to MCT) and quickly back to TOGA this gets the SRS but in GA mode or ignore FDs and fly 17.5 pitch with full back stick if needed. When FDs are there ignoring them is a tough job. If you had moved thrust levers to CLB then you reselect TOGA. You get back SRS in GA,you can follow SRS till default GA acceleration altitude. Also Airbus reccommends not reduce THR RED/ACC ALT if windshear is expected. I have confirmed that even in windshear, at THR RED ALT, LVRCLB wil flash and at ACC ALT SRS will change to CLB.

sonicbum 6th Sep 2014 11:18


Originally Posted by vilas (Post 7734745)
You get back SRS in GA,you can follow SRS till default GA acceleration altitude. Also Airbus reccommends not reduce THR RED/ACC ALT if windshear is expected. I have confirmed that even in windshear, at THR RED ALT, LVRCLB wil flash and at ACC ALT SRS will change to CLB.

Hi vilas,

if you go back to TOGA and trigger the GA phase, the acceleration altitude will be the one set in the GO AROUND PERF page of the FMGC which will be, let's say, 1000 ft AAL of the destination aerodrome, correct ? So let's say if the destination has an elevation of 7000 ft, the SRS will stay there till 8000 ft.
Another question regarding the THR RED and ACC in case of wind shear. Airbus recommends not to reduce THR RED/ACC ALT if wind shear is expected but what about the recommendation to avoid NADP in case significant turbulence or wind shear is expected ? I have a little confusion here. Is there any docs from Airbus supporting the fact that CLB or OP CLB phase will engage at ACC ALT even if Wind shear is triggered ? I tried it in the SIM too and it is like you say but just want to make sure it's not a SIM glitch.

Thanks !

Goldenrivett 6th Sep 2014 11:47

Hi sonicbum,

Is there any docs from Airbus supporting the fact that CLB or OP CLB phase will engage at ACC ALT even if Wind shear is triggered ?
FCOM DSC 22-40
"The windshear detection function is provided by the Flight Augmentation Computer (FAC) in takeoff and approach phase in the following conditions:
- At takeoff, 3 s after liftoff, up to 1,300 ft RA

- At landing, from 1,300 ft RA to 50 ft RA

- With at least CONF 1 selected.
The warning consists of:
- A visual “WINDSHEAR” red message displayed on both PFDs for a minimum of 15 s.
- An aural synthetic voice announcing “WINDSHEAR” three times."

Above 1,300 ft, windshear will not be detected nor displayed, so SRS will change to CLB even if you are still in windshear conditions provided the AA is <=1300.


the acceleration altitude will be the one set in the GO AROUND PERF page of the FMGC which will be, let's say, 1000 ft AAL of the destination aerodrome, correct ?
No.
Destination AA is only used after you have reached cruise ALT or activated the APP phase.

timmyEGCC 6th Sep 2014 12:45


Destination AA is only used after you have reached cruise ALT or activated the APP phase.

Cruise ALT? Can anyone confirm that FMGC can NOT go into GA phase from phases other than APPROACH PHASE? (A320 FCOM DSC-22_20-30-20)?


My understanding also is that SRS GA mode can still trigger regardless of the FMGC phase provided Conf 1 or more selected.















Goldenrivett 6th Sep 2014 15:39

Hi timmyEGCC,

My understanding also is that SRS GA mode can still trigger regardless of the FMGC phase provided Conf 1 or more selected.
Correct, but what AA is used to engage CLB and prompt you to select Climb Power?

vilas 6th Sep 2014 17:37

sonicbum
Actually there is no document that ever said that in wind shear SRS doesn't change or CLB or OPCLB will not engage. But I confirmed it out of curiosity. TOGA after SRS has changed will engage GA mode and SRS will change at default ACC ALT not necessarily of destination. Wind shear detection is a low level function so NADP ACC ALT being 3000ft. it won't apply there.

sonicbum 9th Sep 2014 08:58

Thank You all gents


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