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extricate
20th Sep 2014, 14:51
Hi,

Guess many of you have seen this. United A320 Stunning Breezy Morning Takeoff from Newark and past NYC! - YouTube

This is new to me. Never seen this before. How does this work? I know that the spoilers deployed due to the wind. What's the purpose and where can I find this in the FCTM?

Thanks

BOAC
20th Sep 2014, 15:28
Even allowing for it being an AB, I reckon the ship needs checking for spoiler float.

PS Don't waste your time on the whole video, watch from 13:00 for about 1 minute.:sad:

Reverb_SR71
20th Sep 2014, 15:48
hmm this is unusual .

The spoilers seem to acting independently of the aileron , so i dont think they came out for roll control.

maybe the crew used the spoilers for some reason ? cant really say for sure without looking at the other wing.

TyroPicard
20th Sep 2014, 20:19
Interesting.
Spoilers 2,3&4 deflect upwards about five seconds after lift-off. These are the speed brake panels, selectable by the speed brake lever. For roll control Spoilers 2,3,4&5 operate together (have a look at HD US A320 out of Phoenix Sky Harbour, after T/O, on the same channel).
SEC3 controls spoiler 2, SEC1 controls spoilers 3&4..these two are at the same angle, a different angle to spoiler 2.
Deduction.... this is a small speed brake demand which occurs when Normal Law blends in after lift-off.

My GUESS as to why... Do United still disarm Ground Spoiler immediately on L/G retraction selection, or do they wait until Flaps Zero (airbus SOP since several years ago)? If the PM disarms the Ground Spoilers with a vigorous push it is possible to select a small speed brake demand without realising it...

Of course I could be completely wrong about the "why".

extricate
21st Sep 2014, 10:56
seems like this is new to most of the people here.

Yeah, the spoilers seemed to deploy automatically. Can this be done in strong wings? Company SOP allows this?

And how do they help in aerodynamics if there is a strong headwind? Won't the deployment of spoilers destroy some of the lift component?

Seasoned bus drivers? Care to comment?

B737900er
21st Sep 2014, 11:38
I think the A/C should be checked for spoiler float. You can see from the aileron deflection that the crew must of been fighting it a little.

Old Fella
21st Sep 2014, 12:11
Don't know anything about Airbus, but it would seem to me that this is simply roll augmentation as a result of roll input by the pilot. If a large or rapid roll correction is needed the spoilers on the down-going wing will lift to reduce the lift on that wing. In the video the the spoilers first lift as the aircraft banks right.

tom775257
21st Sep 2014, 13:28
The aileron is at times sat happily with its 5 degree droop with flap extended at its neutral position with the spoilers extended... it can't be for roll control.

I'm going with TyroPicard's explanation. I have seen it twice for real on the A320... once after takeoff, only noticed once the *bing* Ecam caution appeared to warn that the spoilers are extended against power and once leading to a high speed RTO during base training (Ecam threw up T/O config master warning). Airbus SOP changed to disarm ground spoilers now after flap retraction for this very reason.

Guessing here: With the T/O explanation I would think they received the ECAM caution fairly early on, but elected to have a look at it once things settled down a bit on departure.. which is a good thing with an amber caution... then once you have the aircraft on a safe trajectory have a look and diagnose.

Denti
21st Sep 2014, 13:46
The ECAM warning "SPD BRK STILL OUT" is inhibited in that flight phase though, so there should be only the amber "SPD BRK" memo.

tom775257
21st Sep 2014, 14:11
Sorry memory failed me, I guess in that case it makes it even more likely. Thanks for the correction.

TyroPicard
22nd Sep 2014, 18:30
Old Fella ... I agree that you don't know anything about airbus.:O
Roll demand uses four spoiler panels, speedbrakes use three. If it was a sustained roll demand the a/ c would keep rolling; it appears to be a commanded speedbrakes selection.

extricate ... There is no reason to use speedbrakes just after take-off .. you are right that is has a detrimental effect.

Tinwacker
24th Sep 2014, 17:11
Even allowing for it being an AB, I reckon the ship needs checking for spoiler float.

I would originally have agreed but then the spoilers fair just before flaps are fully retracted, then remain so until the flight spoilers rise slightly during the return of the left hand bank to straight and level.
Would have been unusual to have so many spoilers up floating....!
The comments about speedbrake slight input make interesting possibilities.
We don't see the left wing side to confirm other options.

Interesting.

TyroPicard
25th Sep 2014, 17:18
Tinwacker
I cannot imagine any other options.. The a/c does not roll to the right so what does that tell you about the left wing?

ElitePilot
27th Sep 2014, 22:48
Totally agree a case of speed brake deployment on spoilers 2/3/4 so i'll throw a scenario out there...
"Positive Climb", "Gear Up" > Over enthusiastic disarming of the ground spoilers leading to knocking out to about 1/4 deployed unintentionally?
I'm not saying its Airbus SOP but could be a company thing.
Looks like they returned to normal during the clean up so probably saw the memo after the take off inhibit phase. :rolleyes:

dream747
27th Sep 2014, 23:04
In the not to distant past Airbus SOPs were to disarm the spoilers after gear retraction (now it's after flap retraction). Agree with the scenario of the PNF disarming the spoilers too enthusiastically ending up pulling the lever back slightly. Done it before myself. :}

ElitePilot
27th Sep 2014, 23:42
Yeah I know that's why I thought of it, me too. I have OCD though so I always give it a nudge to ensure it's stowed after ;)
Let's not get started on climb performance!

Amadis of Gaul
28th Sep 2014, 11:45
Our procedure still is to disarm them with gear retraction and arm with extension. In fact, we were taught "if you tough the gear lever, don't forget the spoiler lever".

Old Fella
28th Sep 2014, 12:36
TyroPicard. By my own admission I know nothing of the Airbus. Your comment regarding that fact indicates that you know little about humility.

TyroPicard
29th Sep 2014, 12:27
Old Fella..
Apologies if you don't like my banter.. I thought the smiley would indicate that it was just that. I spent about fifteen minutes with my head in the books to make sure my post no.4 was correct before posting it... and then all sorts of folk come up with different incorrect ideas. And some post the same correct answer as their own brilliant scenario... And so it goes...

Old Fella
30th Sep 2014, 08:54
TyroPicard. No worries. I just thought your comment was uncalledfor.