Flight control laws

Question 1

What changes when you go to alternate law?

Answer 1

Auto pilot may not be available. Auto pitch trim usually available. Some protections now stabilities that can be overridden. Still have G load and maybe bank angle and spiral stability.

Ref. A330, Vol 2, 27.3.5

Question 2

What changes when you go to direct law?

Answer 2

Direct side stick to flight controls like conventional aircraft. most importantly no auto pilot and no auto pitch trim. Think Cessna 150. 

Ref. A330, Vol 2, 27.3.6

Question 3

How do you recognize that you’re in alternate law?

Answer 3

Yellow X at 60°

Ref. A330, Vol 2, 27.3.5.2

Question 4

How do you recognize that you’re in direct law?

Answer 4

“MAN PITCH TRIM ONLY” in amber

Ref. A330, Vol 2, 27.3.6.2

Question 5

What is abnormal attitude law? what happens when finished recovery?

Answer 5

Keeps protections and stabilities from interfering with recovery. after recovery Goes to alternate law for rest of flight 

Ref. A330, Vol 2, 27.3.7

Question 6

Back up flight control law?
I will recognize when in ?

Answer 6

For a complete loss of electrics or all flight control computers. Fly with rudder and manual pitch trim only.
“MAN PITCH TRIM ONLY” in red

Ref. A330, Vol 2, 27.3.8

Question 7

Describe how pitch control works in normal law

Answer 7

G load demand. Stick goes to neutral = maintains current pitch. THS always trimmed streamlined. Up to 33° bank get auto pitch trim. Greater than 33° need back stick. At 67° full back stick maintains Max G load of 2.5 gees. Range for G load clean +2.5-1.0 Dirty: 2.0 0.0 Pitch attitude range +30° -15°

Ref. A330, Vol 2, 27.3.2.1

Question 8

What protections are available in normal law?

Answer 8

G load, pitch attitude, airspeed, alpha, alpha floor, bank angle.

Ref. A330, Vol 2, 27.3.4

Question 9

What happens at high speed protection which is VMO +4?

Answer 9

Auto pilot disconnects pitch trim to slow down, Forward stick is allowed no further effect also bank angle limit reduced from 67° to 45° Max.

Ref. A330, Vol 2, 27.3.4.4

Question 10

What happens with Alpha protection? How enter? What are the limits? How get out?

Answer 10

Enter alpha protection at alpha prot which is top of yellow black barberpole. auto pilot disconnects speed brakes stows, G load pitch goes to alpha. Full aft stick stops further alpha increase at alpha max at the bottom of the barber pole. release stick and plane pitches to alpha prot. forward stick necessary to get out of alpha and back to normal law.

Ref. A330, Vol 2, 27.3.4.5

Question 11

What is Alpha floor? When do you enter? How do you get out?

Answer 11

Alpha floor is auto thrust protection. Activates normally between alpha Prot and alpha Max but since it is predictive it may be higher (Slow airspeed and high Bank angle and then sudden pitch up) Thrust goes to toga and when out of alpha floor (alpha) goes to toga lock. Recover by getting out of alpha and then out of toga lock. Match and mash means move thrust levers to toga then disconnect auto thrust return thrust levers to climb and reengage auto thrust with push button on FCU

Ref. A330, Vol 2, 27.3.4.6

Question 12

What is low energy warning and when do you hear it?

Answer 12

Verbal warning “speed, speed, speed”. for low altitude and configured. from 100 to 2000 feet and flaps 2 to flaps 3 or full. usually occurs before reach alpha prot.

Ref. A330, Vol 2, 27.3.4.8

Question 13

What low speed protection do you have in alternate law?

Answer 13

Low speed stability. Replaces alpha protection. 5 to 10 kn above stall goes to direct law and a gentle nose down and Auto pitch trim inhibited. Can be overridden since it’s a stability.

Ref. A330, Vol 2, 27.3.5.3–Low Speed Stability