Flight Control Laws

Question 1

What type of flight control system does the A320 family use?

Answer 1

Fly-by-wire system

Question 2

Describe how the flight controls are controlled and activated.

Answer 2

Electrically controlled and hydraulically activated

Question 3

How is NORMAL LAW indicated on the PFD?

Answer 3

Green “=” for pitch, bank, and overspeed limits; amber/black ALPHA PROT airspeed tape

Question 4

How is ALTERNATE LAW indicated on the PFD?

Answer 4

Amber Xs; speed tape shows VLS and VSW

Question 5

How is DIRECT LAW indicated on the PFD?

Answer 5

Amber “USE MANUAL PITCH TRIM”; amber Xs

Question 6

How is MECHANICAL BACKUP indicated on the PFD?

Answer 6

Red “MAN PITCH TRIM ONLY”; amber Xs

Question 7

In NORMAL LAW, what does sidestick command for pitch and roll?

Answer 7

Pitch: G load; Roll: Roll rate

Question 8

What is the Sidestick Priority (Red Arrow) Light?

Answer 8

Indicates the other pilot has taken sidestick authority

Question 9

Name the flight control computers and how many of each.

Answer 9

ELAC (2), SEC (3), FAC (2)

Question 10

What does SEC 3 control?

Answer 10

One flight spoiler and one ground spoiler on each wing

Question 11

What should happen to the THS after landing?

Answer 11

It resets to zero

Question 12

What protections are available in NORMAL LAW?

Answer 12

High speed, high angle of attack, load factor, pitch attitude, and bank angle protections

Question 13

Describe high speed protection.

Answer 13

Pitch-up command applied to reduce speed if VMO/MMO plus margin is exceeded

Question 14

Can a pilot override high speed protection?

Answer 14

No, not in NORMAL LAW

Question 15

What is ALPHA MAX?

Answer 15

Maximum allowed AOA in NORMAL LAW (top of red tape)

Question 16

Describe High AOA Protection.

Answer 16

At ALPHA PROT, sidestick commands AOA, not G load, up to ALPHA MAX

Question 17

What protections are available in ALTERNATE LAW?

Answer 17

Load factor, high speed stability, low speed stability

Question 18

What protections are available in DIRECT LAW?

Answer 18

None

Question 19

Does flare mode activate in ALTERNATE LAW?

Answer 19

No, aircraft transitions directly to DIRECT LAW with gear down

Question 20

When does ALTERNATE LAW revert to DIRECT LAW?

Answer 20

Gear extension (without autopilot) while in ALTERNATE LAW

Question 21

When is sidestick directly related to control surface movement?

Answer 21

In DIRECT LAW and on the ground

Question 22

Can the Airbus stall in NORMAL LAW?

Answer 22

Yes, if protections misinterpret bad data; pilots must still recognize and recover

Question 23

How does the aircraft enter ABNORMAL ATTITUDE LAW?

Answer 23

Exceeding about twice NORMAL LAW limits

Question 24

What is the purpose of ABNORMAL ATTITUDE LAW?

Answer 24

To help recover from unusual attitudes

Question 25

If flying at 300 knots and sidestick pulled full back, what’s the pitch limit?

Answer 25

30° nose up

Question 26

If pilot selects 100 knots on speed knob with A/P and A/THR on, how slow will it go?

Answer 26

To VLS

Question 27

What happens in NORMAL LAW if thrust is reduced to idle?

Answer 27

Airspeed decays, THS trims to maintain altitude; at ALPHA PROT, pitch function changes

Question 28

What happens if sidestick is held full aft during this scenario?

Answer 28

Aircraft flies to ALPHA MAX, maintaining max safe AOA

Question 29

When does ALPHA FLOOR protection activate?

Answer 29

When AOA threshold exceeded; A/THR applies TOGA power automatically

Question 30

Is ALPHA FLOOR available at all times?

Answer 30

Only in NORMAL LAW, when A/THR is functional, and at least one engine is running; not above M 0.6 on NEO

Question 31

What prevents overstressing the aircraft in NORMAL LAW?

Answer 31

Maneuver protection via flight control computers

Question 32

What happens during an overspeed in NORMAL LAW?

Answer 32

Nose-up input applied; speed reduced; max speed limited even with full forward stick

Question 33

What roll control features are provided in NORMAL LAW?

Answer 33

Roll rate demand, automatic pitch trim to 33° bank, bank angle protection, turn coordination

Question 34

What happens if you release sidestick above 33° bank?

Answer 34

Aircraft rolls back to 33° (positive spiral stability)

Question 35

What happens if pilots are in ALTERNATE LAW?

Answer 35

Amber Xs on PFD; pitch same as NORMAL, roll is direct; most protections lost; stabilities replace them

Question 36

What are stabilities in ALTERNATE LAW?

Answer 36

High and low speed stabilities that inhibit trim but can be overridden

Question 37

What’s the effect of turn coordination in ALTERNATE LAW?

Answer 37

Lost; yaw damping and trim available if a FAC is still operational

Question 38

Describe DIRECT LAW indications and logic.

Answer 38

Amber “USE MAN PITCH TRIM”; no protections or stabilities; pitch and roll both direct

Question 39

What happens when in MECHANICAL BACKUP?

Answer 39

Pitch via trim wheel, roll/yaw via rudder; sidesticks inoperative