Flaps

Question 1

How many flap control units are there (FCUs)?

Answer 1

3

Question 2

Basic function of FCUs?

Answer 2

• Primary Control
• Secondary Control
• Indication/Annunciation

Question 3

How many groups of leading edge flaps and power?

Answer 3

• Three on each wing.

- Pneumatically, via bleed air duct

Question 4

How are trailing edge flaps powered?

Answer 4

HYD SYS 1 and 4

4_1 || 1_4

Question 5

How are opposite trailing edge flaps connected?

Answer 5

Mechanically, prevents asymmetry

Question 6

In primary mode, what protection features are provided by FCUs for trailing edge flaps?

Answer 6

• Asymmetry
• Load Relief
• Position Info

Question 7

What protection features are lost in secondary mode?

Answer 7

Load Relief

• Asymmetry protection still available via FCUs.

Question 8

Why does FCU switch to secondary mode and how do flaps function while in it?

How are flaps commanded to extend/retract ins secondary mode?

Answer 8

If any group fails in primary mode, the FCUs switch to secondary mode for the related group, driving the group through electric motors.

Still commanded with the Flap Lever.

Question 9

What happens if primary control failure occurs in either inboard or mid-span LEF group?

Answer 9

Both groups switch to secondary mode.

Question 10

What happens if failure occurs in LEF group on one wing?

Answer 10

• The flap groups on both wings change to secondary after a short delay of 20-45 seconds
• In that time, the non-affected side completes movement via primary mode, then changes to secondary

Question 11

What happens if TEF asymmetry is detected?

Answer 11

• Primary mode shut down for asymmetric group
• FCUs do not use secondary mode
• FLAP DRIVE on EICAS

Question 12

What EICAS message is displayed if all 3 FCUs fail?

Answer 12

FLAPS CONTROL

Question 13

How does Flap Alternate Control mode work?

Answer 13

• Bypasses FCUs
• Can be manually selected
• All flaps extended/retracted electrically

Question 14

Is there asymmetry protection in alternate flap mode?

Answer 14

NO

Question 15

What happens when ALTN flaps arm switch is pushed?

Answer 15

• Arms flaps alternate control mode
• Arms alternate flaps selector
• Shuts off primary/secondary mode
• Flap Lever Inop

Question 16

What is max flap extension in alternate mode?

Answer 16

25

Question 17

LEF white box outline?

Answer 17

Retracted

Question 18

LEF white crosshatch?

Answer 18

In transit

Question 19

LEF solid green box?

Answer 19

Extended

Question 20

LEF amber box outline, crosshatch, or solid box?

Answer 20

Drive unit inop

Question 21

What does amber “X” mean on expanded flap display?

Answer 21

Position sensor inop

Question 22

Describe Alternate Mode Expanded Flap Position Indicator?

Answer 22

Flap position index marks between 5 and 25

Question 23

What happens to flap position indicator if standby bus is the only powered AC bus?

Answer 23

• Left wing TEF sensors not powered.

- Amber X on left outboard/inboard TEF

Question 24

What flaps extend when lever moved from UP to 1?

Answer 24

LEF, inboard and mid only

Question 25

What flaps extend when lever moved from 1 to 5?

Answer 25

LEF, outboard | TEF

Question 26

Is flap load relief available in secondary or alternate mode?

Answer 26

NO

Question 27

How long does flap indication on EICAS remain displayed after all FLAPS UP?

Answer 27

10 seconds

Question 28

What does flap system do during reverse thrust operation?

Answer 28

Inboard and mid-span LEF retract automatically

Question 29

ALTN Flaps Selector to EXT?

Answer 29

- LEF and TEF extend electrically | - Max extension is Flaps 25

Question 30

ALTN Flaps Selector RET?

Answer 30

- TEF and LEF flaps retract electrically

Question 31

EICAS FLAPS CONTROL?

Answer 31

- All 3 FCUs have failed - or- | - Alternate flaps ARM switch in ALTN

Question 32

EICAS FLAPS DRIVE?

Answer 32

One or more flap groups have failed to drive in secondary mode or an asymmetry condition is detected.

Question 33

EICAS FLAPS PRIMARY?

Answer 33

One or more flap groups operating in secondary mode.

Question 34

How does Flap Load Relief work?

Answer 34

If airspeed limit is exceeded for FLAPS 30, they are retracted to 25. If airspeed is still excessive, they are further retracted to FLAPS 20. Similarly, if FLAPS 25 speed is exceeded, they retract to FLAPS 20.

Question 35

Where are the mechanical flap gates?

Answer 35

``` FLAPS 1 (LEF Inadvertent Retraction) FLAPS 20 (Go Around) ```

Question 36

Secondary flap extension from FLAPS 1 to FLAPS 5 takes approx how long?

Answer 36

4 minutes