Flight Controls

Question 1

1. Name the flight control Laws

Answer 1

Normal law, alternate law, direct law, unusual attitude law mechanical backup

Question 2

2. What is the purpose of mechanical backup

Answer 2

To be able to control the aircraft in the event of the temporary loss of the flight control computers

Question 3

3. What is the purpose of unusual attitude law?

Answer 3

To recover from an abnormal attitude.
Conditions:
Bank angle > +/- 125 degrees
Pitch +50 to -30 degrees
Speed 440kts /0.91 70-90kts>
Display “use man pitch trim” in direct law
Pitch Altn law
Roll DCT law
Yaw Mechanical
Aircraft then remains in alternate law

Question 4

4. In normal law, explain bank angle protections

Answer 4

0-33 degrees the aircraft will be autotrimmed and remain at set angle within 33 degrees. 33-67 degrees the max bank angle, if sidestick released, aircraft will roll back towards 33 degrees to give spiral stability.

Question 5

5. What is the maximum bank angle when α protection is in force

Answer 5

45 degrees- no FDs beyond 45 degs, return at 40 degs

Question 6

6. What’s the maximum bank angle when high speed protection is in force

Answer 6

40 degrees- due to load factor, if sidestick returned to neutral, the bank angle will return to zero

Question 7

7. When in α prot what happens when you release the sidestick

Answer 7

The speed will settle above the alpha protection band.

Question 8

8. What is the max pitch available in clean config and config full

Answer 8

-15 (no FDs beyond -13 but return -10) to +30 degs (clean to conf 3)
-15 (no FDs beyond -13 but return -10) to +25 degs, no FDs beyond+20 (conf full)

Max pitch will reduce by 5 degs during alpha protection (+25 and +20 respectively)

Question 9

9. What is the max g load in clean and other configs

Answer 9

Clean- +2.5 -1.0
Other - +2.0 -0.0

Question 10

10. Can you explain α prot, α Floor and αMax

Answer 10

αprot- alpha protection, extra layer of protection before alpha max. Side stick goes from g load to alpha. Continue pulling back to αmax can maintain safe envelope during evasive manouvres

αfloor- autothrust protection that commands TOGA to assist with performance and aid recovery

αmax- maintains a protection above the aerodynamic stall of the aircraft

Question 11

11. Once out of the αfloor condition, what thrust mode would you expect to see and how would you recover

Answer 11

TOGA LOCK- locked in TOGA, released by disconnecting A/T returning to clb gate and re-engaging the autothrust.

Question 12

12. What is Vls and it’s relation to the stall speed

Answer 12

VLS- lowest selectable speed
Represented by the top of an amber strip along the airspeed scale.
Computed by FAC corresponds to 1.13vs at takeoff or following touch and go
- becomes 1.23vs after retraction of one step of flaps
-becomes 1.28vs when in clean config

If in CONF 0 VLS were 1.23vs instead of 1.28vs the alpha protection strip would hit the VLS strip on the PFD

Question 13

13. Can high speed protection be overridden

Answer 13

Yes- by pitching forward in case of a TCAS RA
The structural speed will not be exceeded by reducing side stick input to 0

Question 14

14. Draw the speed tape in alternate law and in normal law

Question 15

15. When might you see “use man pitch trim” and when might you see “Man Pitch trim only”

Answer 15

Direct law - use man pitch trim
Mechanical backup - man pitch trim only

Question 16

16. What is α Lock and when might you see it?

Answer 16

Inhibits slats retraction at high angles of attack and low speeds ie if you try to move flap lever too early.

Question 17

17. In alternate law explain high and low speed stability

Answer 17

Vmo/mmo- still have the overspeed warning and ECAM. Aircraft will try to pitch up but can be overridden. When pitching down you can overspeed and overstress the aircraft.

VLS

VSW- 5-10kts above the stall speed, aircraft will try to pitch down but you can stall the aircraft if overridden.

Question 18

18. What protections do we have in direct law?

Answer 18

There are no protections. PFD “use man pitch trim”

Question 19

19. What control surfaces have a mechanical link to the flight deck

Answer 19

Rudder
Stabiliser trim

Question 20

20. What is the purpose of aileron droop and how do you know if your aircraft is fitted with it?

Answer 20

Droop- a function of when the flaps are extended. Droop- 5-10 degs to give the wing form extra lift.

Question 21

21. In pitch, how long does it take to transition from ground to flight mode

Answer 21

In pitch there is a blend of 5 seconds. In roll its instantaneous

Question 22

22. What is ground mode?

Answer 22

When flight controls have a direct side stick/rudder pedals to control surface relationship allowing full deflection.

No autotrim.

During take off >70kts max elevator deflection reduces from full 30 down to 20 degrees.

Question 23

23. What is flare mode?

Answer 23

Induces to allow the pilot to flare in a conventional way by pitching down by -2 degrees over 8 seconds at 30ft forcing the pilot to counter this through flare.

At 50ft the aircraft memorises the pitch attitude and freezes the trim.

Question 24

24. What computer controls the characteristic speeds displayed on the PFD?

Answer 24

The FACs (flight augmentation computers)

Question 25

What is the low energy alert and when would it occur?

Answer 25

The aural “SPEED SPEED SPEED” repeated every 5 secs warns the flight crew that the aircraft’s energy level is going below a threshold under which the crew has to increase thrust in order to regain a positive flight path angle through pitch control.

Available in CONF 2, 3 and FULL. The FAC computes energy level from the following inputs:

• aircraft configuration
  -horizontal deceleration rate
• flight path angle

Question 26

Explain the purpose of the beta target and when might you see it?

Answer 26

If one engine fails, the FAC modifies sideslip indication slightly to show the pilot how much rudder to use to get the best climb performance (ailerons to neutral and spoilers retracted)