A350 Flight Controls

Question 1

How many PRIM’s and SEC’s does the A350 have?

Answer 1

• 3 PRIM’s

- 3 SEC’s

Question 2

How many spoilers/speed brakes does the A350 have?

Which ones are used for roll control?

Answer 2

• 7

- 3 to 7

Question 3

What surfaces are used for pitch control?

Answer 3

• Two elevators

- THS

Question 4

What surfaces are used for roll control?

Answer 4

• 4 ailerons

- 10 spoilers

Question 5

What surfaces are used for yaw control?

Answer 5

One rudder

Question 6

What surfaces are used for speed brake and ground spoiler functions?

Answer 6

14 spoilers

Question 7

What surfaces are used for lift augmentation?

Answer 7

• 14 slats
• 4 flaps
• 4 ailerons

Question 8

What is BCM and what does it do?

Answer 8

• Backup Control Module

- Provides aircraft control and stability in case of all PRIM’s and SEC’s fail

Question 9

What is PFTU and what does it do?

Answer 9

• Pedal Feel and Trim Unit
• Trims the rudder pedals to reflect rudder position
• To reflect autopilot trim orders

Question 10

What are EHA’s?
How do they work?
What types of EHA’s are there?
How are they driven?

Answer 10

• Electro-hydraulic actuator
• Uses electricity to generate its own hydraulic power
• Electro-Hydrostatic Actuators (one elec system)
• Electrical Backup Hydraulic Actuators (powered by elec or hydraulic system)

Question 11

Above what speed do the outer ailerons remain in the neutral position?

Answer 11

250kts

Question 12

What happens when the hydraulic power to the spoilers is lost?

Answer 12

• If retracted, they remain retracted
• If extended below balanced position, remains in that position (may change with air raft speed)
• If extended above balanced position, retracts to the balanced position (blowback)

Question 13

What is the ADHF?

What does it do?

Answer 13

• Adaptive Droop Hinge Function

- Droops the spoilers down to controls the gap between the spoilers trailing edge and flaps leading edg

Question 14

What is LAF?

Answer 14

• Load Alleviation Function made up of
• MLA (Manoeuvre Load Alleviation)
• GLA (Gust Load Alleviation)
• DFS (Differential Flap Setting)

Question 15

What is ADGB and what does it do?

Answer 15

• Active Differential Gear Box

- Allow independent control of inner and outer flaps for DFS

Question 16

What is the Slats/Flaps Cruise Baulk Function?

Answer 16

• Inhibits slats/flaps extension during cruise when flap selector accidentally moved to position 1
• Does not work for flap 2,3, full

Question 17

What is the FLAPS lever override mechanism?

Answer 17

• In the event the FLAPS lever is jammed the lever can be pushed back by one step with force without first taking it out of the detent
• Will only extend flap by 1 position
• Is reversible