Flight Controls -Flaps & Slats DSC 27-30

Question 1

Each wing has how many flaps?

Answer 1

2

Question 2

Each wing has how many slats?

Answer 2

5

Question 3

How are the flaps and slats controlled and operated?

Answer 3

Electrically controlled

Hydraulically operated

Question 4

What are the main components of the slat/flap system?

Answer 4

1. 2 Slat Flap Control Computers (SFCC’s)
2. A power control unit
3. 5 slat & 2 flap surfaces per wing
4. An Asymmetry position pick-off unit
5. A Flap disconnect detection system
6. Wing Tip Brakes
7. Feedback position pick-off units
8. Instrumentation position pick-off unit

Question 5

How many channels do the SFCC’s have?

Answer 5

One slat channel and

One flap channel

Question 6

What does the power control unit consist of?

Answer 6

2 independent hydraulic motors coupled by a differential gearbox

Question 7

Which hydraulic systems power the slats?

Answer 7

Green and Blue

Question 8

Which hydraulic systems power the flaps?

Answer 8

Green and Yellow

Question 9

What component locks the transmission when the slat or flap surfaces have reached the selected position, or if hydraulic power fails?

Answer 9

Pressure-off brakes (POBs)

Question 10

What does the asymmetry position pick-off (APPU) measure?

Answer 10

The slat or flap asymmetry between the left and right wings

Question 11

What does the flap disconnect detection system detect?

Answer 11

Attachment failure and inhibits flap operation in order to prevent further damage

Question 12

How does the Flap Disconnect Detection system sensor detect a failure?

Answer 12

By measuring excessive differential movement between inner and outer flaps

Question 13

When are Wing Tip Brakes (WTB) activated?

Answer 13

Asymmetry
Mechanism overspeed
Symmetrical runaway
Uncommanded movement of the surfaces

Question 14

Can WTB be released in flight?

Answer 14

No

Question 15

Which hydraulic systems do the WTB use?

Answer 15

Green and Blue -Slats and Right Wing Flaps

Green and Yellow -Left wing FLaps

Question 16

If the slat WTB’s are on, can the pilot still operate the flaps?

Answer 16

Yes

And if the slat WTB’s are on the flaps are still operable

Question 17

At what speed do the slats and flaps operate if one SFCC is inoperative?

Answer 17

Half speed

Question 18

At what speed do the slats and flaps operate if one hydraulic system is inoperative?

Answer 18

Half speed

corresponding surfaces, slats or flaps

Question 19

If a take-off is carried out at heavy weight, what two protections may intervene?

Answer 19

• Automatic Retraction System (ARS)

- Alpha Lock function

Question 20

When will the Automatic Retraction System activate?

Answer 20

When in CONF 1+F and IAS reaches 210kts

VFE CONF 1+F = 215 kts

Question 21

What happens when Automatic Retraction system activates?

Answer 21

While in CONF 1+F and IAS reaches 210kts (VFE-5kts)

Flaps automatically retract to 0.
VFE now CONF 1 (230 kts)

Question 22

What is the purpose of the Alpha/Speed Lock function?

Answer 22

Inhibits slat retraction at:

High angles of attack, and
Low speeds

At the moment the flap lever is moved from Flaps 1 to flaps 0

Question 23

What information do the SFCC’s use to inhibit slat retraction as part of the Alpha/Speed Lock function?

Answer 23

Corrected AoA or airspeed information from the ADRIU’s

Question 24

When the FLAPS lever is set to 0, the slats allpha/speed lock function will activate and inhibit slat retraction if:

Answer 24

1. The AoA is above 8.5°, or

2. The speed is less than 148 kts

Question 25

How do you know the Alpha Lock function has activated?

Answer 25

‘A-LOCK’ pulses green (cyan-YUD) above the E/WD slat indication

Question 26

When is the Alpha Lock inhibition removed and the slats retract to 0?

Answer 26

When both Alpha and Speed fall within normal values:

AoA less than 7.6°, and

Speed above 154 kts

Question 27

Is Alpha Lock function activation a normal situation for a heavy weight take-off?

Answer 27

Yes

Question 28

What should the crew do if Alpha Lock function is activated?

Answer 28

Continue the normal acceleration, allowing further slats retraction

Question 29

The VMAX on the PFD is based on…..?

Answer 29

The Slat/Flap Control lever position

Question 30

The OVERSPEED WARNING is based on….?

Answer 30

The actual Slat/Flaps surface position

Question 31

What does amber FLAP, slat/flap position, S and F indications indicate?

Answer 31

Both relevant hydraulic systems fail

WTB are on

Slats or flaps fault