Flight Controls

Question 1

How many groups of Leading Edge Flaps (LEF) on the 747, and how do they normally operate?

Answer 1

3 groups, Inboard, Midspan, and Outboard. Normally Pneumatically powered, however in Alternate mode, the LEF are electrically powered.

Question 2

What are they groups of Trailing Edge Flaps (TEF), and how are they powered?

Answer 2

Inboard and Outboard. Inboard powered by HYD 1, and Outboard powered by HYD 4.

Question 3

Is there flap asymmetry protection in alternate mode?

Answer 3

No.

Question 4

How are the TEF driven in primary mode?

Answer 4

Hydraulically.

Question 5

How long does the flap indicate on the Primary EICAS remain displayed after all flaps are up?

Answer 5

10 seconds.

Question 6

What protection features do the Flap Control Units (FCU) provide for Trailing Edge Flaps in primary mode? (3 Items)

Answer 6

Asymmetry Protection,
Load Relief, and
Relays flap position information to the EICAS and other systems.

Question 7

How many FCU’s are there?

Answer 7

3.

Question 8

What is the maximum position of flaps attainable in alternate mode?

Answer 8

Flaps 25.

Question 9

What EICAS message would be shown if all three FCU’s fail in their control function?

Answer 9

‘FLAPS CONTROL’

Question 10

How does the Flaps Alternate Control work? (3 Items)

Answer 10

Bypasses the FCU’s,
All flaps controlled electronically, and
Manually selected.

Question 11

Is there flap asymmetry protection in alternate mode?

Answer 11

No.

Question 12

What happens if a primary control failure occurs in either Inboard or Midspan Leading Edge Flap group?

Answer 12

Both groups switch to secondary mode.

Question 13

When do the spoilers extend to the up position after landing, if the speedbrake lever is NOT armed? (3 Items)

Answer 13

Engine 1 and 3 thrust levers at Idle,
Main landing gear on ground, and
Engine 2 or 4 thrust reversers in the idle position.

Question 14

On the 747-8, to improve takeoff performance and reduce noise, outboard ailerons are deflected down at which flap settings? Return to neutral at which flap settings? Inboard ailerons droop at which settings? (3 Items)

Answer 14

10 or 20,
25 or 30,
10 or greater.

Question 15

Describe the function of the Stab trim cutout switches in the ‘AUTO’ Position? (2 Items)

Answer 15

Provides hydraulic power to actuate stabilizer trim,
Cuts off hydraulic power if unscheduled trim is detected.

Question 16

What is the effect on the flaps during operaton of the thrust reversers?

Answer 16

Inboard and Midspan LEF are retracted.

Question 17

What surface component is moved when stabilizer trim inputs are made?

Answer 17

Leading edge of the horizontal stabilizer moves.

Question 18

What is the purpose of Yaw Dampers? (2 Items)

Answer 18

To improve lateral and directional stability, and

Assist in turn coordination.

Question 19

How does the Aileron Lockout system work, and what is its purpose?

Answer 19

At speeds above 238 kts, the outboard ailerons are locked in the neutral position, to prevent over controlling, and prevent structural damage.

Question 20

What system assists the 747-8 in pitch stability and landing flare?

Answer 20

Pitch Augmentation Control System (PACS)

Question 21

When does the 747-8 takeoff and landing tailstrike prevention activate?

Answer 21

When the PACS sense imminent tailstrike, it will decrease elevator deflection.

Question 22

Takeoff Trim setting is calculated based on what? (4 Items)

Answer 22

Aircraft CG,
Gross Weight,
Takeoff Derate Selection, and
Takeoff Flap selection (747-8 only).

Question 23

Will pushing the control wheel stabilizer trim switches with multiple autopilots engaged disconnect the AP system?

Answer 23

No.