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Airbus 320 Speedbrakes Vs Flaps

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Airbus 320 Speedbrakes Vs Flaps

Old 16th Oct 2010, 13:08
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Airbus 320 Speedbrakes Vs Flaps

FCOM 3.03.18

- FLAPS 2 .... SELECT
. If the aircraft speed is signaficantly higher than S on glide slope or it doesnt decelerate EXTEND landing gear to slow it down.. USE of speedbrakes are not recommended.

. When the speedbrakes are deployed extending FLAPS beyond FLAPS 1 may induce a slight roll movment, and in calm conditions a small lateral asymtry may remain untill controled....


------------------------

1st point.. So deploying SPEEDBRAKES are still allowed but not recommended..

2nd point.. (confusion ) IS the speedbrakes deployment not recommended when flaps are already at (2)
CONDITION:
A/C: FLAPS ARE AT 2
YOU DEPLOY SPEEDBRAKES

.. OR when speedbrakes are deployed and then you select Flaps 2 ???
A/C:
SPEEDBRAKES ALREADY DEPLOYED
YOU ORDER FLAPS 2


AIRBUS 320 MASTERS PLEASE HELP..

THANKS
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Old 16th Oct 2010, 14:16
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There is a longstanding (software?) glitch in that some A320's do roll quite quickly to @10-15aob either at F2 and then extending speedbrake or F1 speedbrake out and then selecting F2.
Can be quite fun if you get a good one!! but roll input may be suffiecent to break out the LOC signal when descending on the glide.
I've intercepted the LOC many times in a computer induced , cross controlled left turn but wimp out when LOC# and restow the speedbrake.
F2 and selected speed of @185 knts gives very good compromise between ROD, manoueverability and control of aircraft energy state.
This only seems to apply to A320. ie full speedbrake only available with autopilot out, half speedbrake with AP engaged.
Friday afternoon software designers?
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Old 16th Oct 2010, 16:59
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thanks charls

anyone can inlight and explain the fcom 3 words above thanks
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Old 16th Oct 2010, 19:02
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Hi,

Our OPS manual permits the use of Speed brake & Flaps - if it's necessary in order to be stable in a timely manner. The FCTM contains the following health warning:

"In certain circumstances, e.g. tail wind or high weight, the deceleration rate may be insufficient. In this case, the landing gear may be lowered, preferably below 220 kt (to avoid gear doors overstress), and before selection of Flap 2. Speedbrakes can also be used to increase the deceleration rate but the crew should be aware of:
The increase in VLS with the use of speedbrakes
The limited effect at low speeds
The speed brake auto-retraction when selecting the landing configuration. (Not applicable for A318)"

I've not noticed any unwanted roll, but gentle control of the speed brake is advised to avoid rapid pitch changes. On some types the auto thrust needs to be reset as it may hold 10 kts faster than commanded.

Last edited by rudderrudderrat; 16th Oct 2010 at 19:46. Reason: typo
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Old 16th Oct 2010, 21:36
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and before selection of Flap 2. Speedbrakes can also be used to increase the deceleration rate but the crew should be aware of:
It might mean speedbrakes use before selection flap 2 too!!
Again its not that clear..

in reality i found using speedbrakes in flap 2 config to decelerate in tailwind cond.. more effecient and realiable than lowering landing gear..

but is it recommended to use speed brakes with flap 2...

CONFIG FLAP 2
YOU DEPLOY SPEEDBRAKES !


??
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Old 16th Oct 2010, 22:00
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Hi Captain_BH,

Affirm. I've used speed brakes with F2 in order to decelerate to the requested ATC speed.
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Old 17th Oct 2010, 17:03
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Why fuss about using the speedbrake?

In my opinion, anyone using the speedbrake below 200kt is a drowning man grasping at a straw.................. for everyones sake drop the damn gear. If you are that high on energy at that point, make a positive step towards control.

Airbus state that the speedbrake has minimal effext below 200 (220?) knots.

Too many people are addicted to the 'chicken stick' and wont stick the gear out before flap 2. It works so nicely, and saves those skid marks in the boxers!!
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Old 20th Oct 2010, 02:25
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You are right regarding below 200 kts and the effect of speedbrakes.. but sometimes all you need if that little bit more without having to deploy the landing gear. From my personal experience I wouldn't say its the speedbrakes per sa, but the 3-4 degree increase in nose attitude to maintain a 3 degree profile tends to put a lot of body into the airflow which can work well, especially at lighter weights.

If you are high I find 210kts and config 1 and 1/2 brake works a treat. You receive about a 7-10% decent profile.... beautiful!
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Old 20th Oct 2010, 09:48
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As I read it ...

FCOM 3.03.18

- FLAPS 2 .... SELECT
. If the aircraft speed is signaficantly higher than S on glide slope or it doesnt decelerate EXTEND landing gear to slow it down.. USE of speedbrakes are not recommended.
This is the recommendation. If you are at flap 2, don't use the speed brake.

. When the speedbrakes are deployed extending FLAPS beyond FLAPS 1 may induce a slight roll movment, and in calm conditions a small lateral asymtry may remain untill controled....
... and this is the explanation - if you use speed brake at any time with more than flap 1, you have roll problems. This simply means flap 2 and speedbrake can be a problem - it doesn't matter which is selected first, as long as you don't have both together.
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Old 22nd Oct 2010, 11:53
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As always, there is plenty of valuable information in AB manuals. Nobody ever understood just where.

FCTM: GLIDE SLOPE INTERCEPTION FROM ABOVE
... In order to get the best rate of descent ... the crew should lower the landing gear and select Config 2. Speedbrakes may
also be used, noting the considerations detailed in the sub-section "Deceleration
and configuration change" earlier in this chapter.
DECELERATION AND CONFIGURATION CHANGE
In certain circumstances, e.g. tail wind or high weight, the deceleration rate may
be insufficient. In this case, the landing gear may be lowered, preferably below
220 kts (to avoid gear doors overstress), and before selection of Flap 2.
Speedbrakes can also be used to increase the deceleration rate but the crew
should be aware of:
. The increase in VLS with the use of speedbrakes
. The limited effect at low speeds
. The speed brake auto-retraction when selecting the landing configuration. (Notapplicable for A318)


Yours,
FD (the un-real).
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