Flight Control Laws Flashcards

1
Q

What are Laws in Airbus?

A

Protections that are electronically activated and hydraulically operated that operate within preset limits

The side sticks or AP sends a rate demands to the flight control computers, which process the demand and send it to the control surfaces. The process uses a pre-set of limitations called LAWS

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2
Q

What are the Flight Control Laws?

A
  1. Normal Law
  2. Alternate Law (with and without reduced protection)
  3. Direct Law
  4. Mechanical Backup
  5. Abnormal Attitude Laws
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3
Q

What are the 3 modes of Normal Law?

A
  1. Ground mode - operates on the ground when the aircraft is electrically and hydraulically powered.
  2. Flight mode - operates in the air with a gradual transition from ground mode. Starts at 50’ or 8 secs after lift off and ends at 50’ for Flare mode
  3. Flare mode - modifies the landing mode to introduce a conventional feel to the landing phase
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4
Q

What are the protections of Normal Law?

A
  1. Pitch Attitude protection
  2. Load factor limitation
  3. High angle of attack protection
  4. High speed protection
  5. Bank angle protection
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5
Q

In normal law, are auto turn coordination and dutch roll damping provided?

A

Yes. Pilot inputs are not required

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6
Q

Normal Law/LFL: Load Factor Limitation limits are: (clean / flaps extended)

A

Clean: 2.5g to - 1g

Flaps extended: 2.0g to 0g

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7
Q

Normal Law/PAP: Pitch attitude protection nose up and down limits?

A

Nose up:
Config 0 to 3: 30deg up
Config full: 20 deg up

Nose down: 15deg

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8
Q

Normal Law/PAP: In pitch attitude protection, when do the flight directors disappear and when do they come back?

A

Flight directors disappear passed 25 deg up and 13 deg down, they return passing 22 deg up and 10 deg down

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9
Q

Normal Law/HAoA: Which protection is the priority among all other protections in Normal Law?

A

High Angle of Attack protection

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10
Q

Normal Law/HAoA: What is the purpose of the high angle of attack protection?

A
  1. Protection from a stall

2. To provide optimum performance during windshear or GPWS recovery

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11
Q

Normal Law/HAoA: On the speed tape, during Normal Law, what are the 3 symbols on the lower part of the speed scale? 2 in amber and 1 in red

A

VLS
Va PROT
Vs MAX

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12
Q

Normal Law/HAoA: What is VLS? Can this be exceeded down to Va PROT?

A
  1. Lowest selectable speed, speed will not go down to Va PROT with the Autothrust engaged
  2. With the auto thrust off, the speed may go down to Va PROT
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13
Q

Normal Law/HAoA: What are Va PROT, Va MAX, Vsw (shown on the lower end of the speed tape)?

A

Va PROT
The AOA protection speed. Angle of attack where AOA protection becomes active. Autothrust not engaged.

Va MAX
Maximum angle of attack speed. Maximum AOA that may be reached under normal law. Reached using max side stick pull back. When the stick is released, speed will go back to Va Prot.

Vsw
Stall warning speed displayed on the PFD when not in normal law

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14
Q

Normal Law/HAoA: With the speed at Va PROT, will the auto pilot engage?

A

No. If it were connected, it will disconnect

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15
Q

Normal Law/HAoA: What are Va PROT, Va FLOOR and Va MAX based on?

A

The AOA

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16
Q

Normal Law/HAoA: In other laws other than Normal Law, what will be left of the lowest speed protections?

A

In alternate, direct law, Va PROT and Va MAX are lost, instead there will be VLS then Vsw. You still get a stall warning

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17
Q

Normal Law/HAoA: When is Va FLOOR activated?

A

When the speed drops between Va PROT and Va MAX

Go around thrust will be automatically set

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18
Q

Normal Law/HAoA: Where is A. FLOOR shown to the pilot when it is activated?

A

On the PFD FMA and the E/WD

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19
Q

Normal Law/HAoA:

Alpha Floor is available from?

A

Lift off until 100ft RA on approach

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20
Q

Normal Law/HAoA: Which computer generates the signal that triggers the alpha floor mode?

A

FAC

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21
Q

Normal Law/HAoA: When is Alpha Floor lost?

A
  1. In either alternate or direct law

2. In an engine out with slats/flaps extended

22
Q

Normal Law/HSP: How are the symbols of the High Speed Protection displayed to the crew?

A

Via the PFD speed scale, the top part. Red and black barber pole tip and an amber equal sign beside it.

23
Q

Normal Law/HSP: How is VMO / MMO high speed protection activated? When does the AP disconnect?

A

On the speed scale, where the red and black barber pole is, the tip is where VMO / MMO is. The green amber equal sign beside it to the left is where the protection is activated (VMO+6).

AP disconnects at VMO + 15 / MMO + 0.04

24
Q

Normal Law/HSP: What happens when the speed is exceeded?

A
  1. Passing the green equal sign, the autopilot will disengage (VMO+15 / Mach+0.04) and the flight control computers will give a pitch up attitude to prevent further increase in speed.
  2. Max THS is limited between and the setting at the point where the aircraft entered this protection and a nose up at 11 deg
  3. With the flight stick released, speed will return to VMO / MMO
  4. The pilot cannot override the automatic pitch up
  5. With the side stick released, the bank angle will return to 0 deg, max bank is down from 67 to 40 deg
25
Q

Normal Law/BAP: How is the bank angle protection in normal law displayed to the pilot?

A

Two green equal signs on both sides of the PFD attitude display

26
Q

Normal Law/BAP: The flight directors will disappear when the pilot exceeds XX deg of bank. They will return when?

A

45 deg and return passing 40 deg

27
Q

Normal Law/BAP: Maximum angle of bank protection is?

A

67 deg bank left or right

28
Q

Normal Law/BAP:
A. What are the limits on bank when:
1. AOA protection is active or
2. High speed protection is active

B. What happens when the side stick is released during a bank with high speed protection is active?

A
  1. AOA: 45 deg
  2. High speed: 40 deg
    B. Aircraft will have a spiral stability where bank will return to 0 deg
29
Q

Normal Law/BAP: What happens to the Automatic Pitch Trim when we exceed 33 deg bank?

A

It is inoperative past 33 degrees and the aircraft will start to sink

30
Q

Normal Law/BAP: What happens to the automatic turn coordinator past a bank 33 deg?

A

Automatic turn coordinator is active until 67 deg. No need to apply manual rudder

31
Q

Normal LAw/BAP: When the side stick is released and banking above “XX” deg, the aircraft will return to this angle of bank

A

33 deg

32
Q

Normal Law/BAP: In normal flight with normal bank, less than 33 deg, what can we expect when we bank?

A
  1. A command for a turn is given and if less than 33 deg, the bank will maintain
  2. No need to adjust for pitch
  3. No need to use the rudder
33
Q

Reconfiguration Laws: What are reconfiguration laws

A

Multiple or dual system failures that degrade the flight control normal laws

34
Q

Reconfiguration Laws:

What are the 3 levels of Reconfiguration Laws?

A
1. Alternate Law
A. With reduced protections
B. Without reduced protections
2. Direct Law
3. Mechanical Back Up
35
Q

Reconfiguration Laws/AL:

How does Alternate Law affect the Normal Law modes?

A
  1. Ground: is the same as normal law
  2. Flight mode:
    A. Pitch control - same as normal law
    B. Roll - conventional
    C. Yaw control - turn coordinator is lost, limited damping
  3. Landing mode: with gear down, goes into direct law
36
Q
Reconfiguration Laws/AL:
What happens to the following in alternate law with reduced protection?
1. Pitch protection?
2. Bank angle protection?
3. Load factor limitation?
4. High angle of attack protection?
5. High speed protection?
A
  1. Pitch limits are lost but auto trim still works, aircraft will keep pitch
  2. Bank angle protection is lost, limited yaw damping, roll is in direct law
  3. Load Factor Limitation is the same as normal law
  4. Replaced by Low Speed Stability
  5. Replaced by High Speed Stability
37
Q

Reconfiguration Laws/AL: What is Low Speed Stability?

A

High angle of attack protection is replaced by Low Speed Stability.
A. Loss of Va Prot and Va Max, Alpha Floor (aircraft can stall)
B. Replaced by a stall warning speed Vsw which introduces a small nose down input to prevent speed loss, can be over ridden by the pilot
C. Aural stall warning

38
Q

Reconfiguration Laws/AL: What is high speed stability?

A

High speed protection is replaced by High Speed Stability.

  1. Reaching MMO / VMO, a slight pitch up is introduced by the aircraft to prevent further speed increase.
  2. This can be over ridden by the pilots. 3. Aural warning with over speed warning chimes
39
Q

Reconfiguration Laws/AL: In summary, what are the reduced protections in Alternate Law?

A

Summary:
Alternate law with reduced protections is:
1. Load Factor Limitation
2. High and Low Speed Stability

40
Q

Reconfiguration Laws/AL:

What is left when you are in Alternate Law without reduced protections?

A
  1. Load Factor Limitation remains.

2. Aural stall and high speed warnings (only the warnings)

41
Q

Difference between alternate law with reduced protections vs alternate law without reduced protection?

What happens when the landing gear is brought down?

A

Alternate Law with reduced protections has high speed and low speed stability (can be overriden by the pilots) and load factor protection

Alternate Law without reduced protections only has load factor protection

When the landing gear is brought down, the aircraft goes into direct law

42
Q

Reconfiguration Laws/DL:

What is Direct Law?

A
  1. Lowest level of computer control
  2. Pilot inputs are sent directly to the control surfaces unmodified
  3. Loss of all protections
43
Q

Reconfiguration Laws/DL:

What if any protections are remaining under direct law?

A

Only aural Stall and Over Speed warnings

44
Q

Reconfiguration Laws/DL:

Is there auto trim in direct law?

A

No. USE MAN PITCH TRIM is displayed on the PFD

45
Q

Reconfiguration Laws/DL:

Does the Auto turn coordination and dutch roll damping still work in direct law?

A

They are lost and all yaw control is done via the rudder pedals only

46
Q

Reconfiguration Laws/MB:

What is Mechanical Backup Mode?

A
  1. Pitch is via the pitch trim wheel, adjusting the THS, provided green or hydraulic system is available
  2. On the PFD, in red, MAN PITCH TRIM ONLY
  3. Roll is through the rudders through a mechanical linkage with the rudder provided at least one hydraulic system is available
47
Q

Can systems be reset to bring the aircraft back to a safer state? Say from Mechanical Back Up Mode back to either alternate or direct law?

A

Yes. Depending on the type of failure, resetting systems can recover into either alternate or direct law. The idea of Mechanical Back Up Mode is to give the crew time to reset systems

48
Q

What is the Abnormal Attitude Law?

A

When the aircraft exceeds the flight envelopes, the abnormal attitude law engages to provide maximum efficiency to the PF to recover the attitude

The idea is to bring back the aircraft back within the normal flight envelope.

The system will revert to alternate law but no direct law transfer when the landing gear is brought down. The aircraft will remain in alternate law

49
Q

When does the abnormal attitude law engage?

A

When one of the following:

  1. Bank is greater than 125 deg
  2. Pitch is nose up 50 deg and nose down 30 deg
  3. Speed is below 70-90kt (depending on attitude)
  4. Mach above .91
  5. AOA is above 40 deg
50
Q

What is the point of mechanical back up law?

A

Buy time, to be able to reset some systems and maybe get back to alternate or direct law?