Flight Control Laws

Question 1

What does the mnemonic BYPALS stand for, and what does it describe?

Answer 1

It describes the basic flight envelope:

• Bank
• Yaw
• Pitch
• AoA
• Load
• Speed

Question 2

What does the mnemonic BASAP stand for, and what does it describe?

Answer 2

It describes the Alpha Prot (which are the low speed) protections:

• Bank 45°
• Autopilot disconnect
• Speedbrakes retract
• AoA instead of load
• Pitch up trim inhibit

Question 3

What does the mnemonic BASN stand for, and what does it describe?

Answer 3

It describes the high speed protections:

• Bank 40°
• Autopilot disconnect
• Seeks wings level
• Nose up movement

Question 4

What does the mnemonic PAR AAA stand for, and what does it describe?

Answer 4

It describes the functions of the ELAC (Elevator Aileron Computer):

• Pitch
• Abnormal Attitudes
• Roll
• Aileron droop
• Autopilot acquisition
• Activates the protections

Question 5

What does the mnemonic PAR SS stand for, and what does it describe?

Answer 5

It descibes the functions of the SEC (Spoiler Elevator Computer):

• Pitch
• Abnormal attitudes
• Roll
• Speed brakes
• Spoilers

Question 6

What does the mnemonic B SWFT & RATTY stand for, and what does it describe?

Answer 6

It describes the functions of the FAC:

• Beta target
  
  • Flaps 1, 2, 3
  • One engine > 80% N₁ and the difference between N₁s exceeds 35%.
  • FAC controls the side slip indication to give best single engine performance
• ”Speed, speed, speed!”
  
  • Given by Low Energy Warning
  • Flaps 2-F, below 2000 feet to 100 feet
  • Forewarns you what is coming?
  • Alpha Floor — available from liftoff, up to cruise, and back down to to 100 feet on approach
• Windshear
  
  • Reactive
  • 3-5 seconds = 50-1300 ft / 1300-50 ft
  • Windshear on PFDs
• Flight Envelope Protections
  
  • Left side PFD
• Tail — controls the following functions
  
  • Rudder limiting
  • Alternate Law yaw
  • Turn coordination
  • Trim
  • Yaw damping

Question 7

What are the ELACs, and what do they do?

Answer 7

ELAC = Elevator Aileron Computer

“PAR AAA”

• Pitch
• Abnormal attitudes
• Roll
• Aileron droop
• Autopilot acquisition
• Activates the protections

Question 8

What are the SECs, and what do they do?

Answer 8

SEC = Spoilers Elevator Computer

“PAR SS”

• Pitch
• Abnormal attitudes
• Roll
• Speed brakes
• Spoilers

Question 9

What do the FACs do?

Answer 9

It describes the functions of the FAC:

• Beta target
  
  • Flaps 1, 2, 3
  • One engine > 80% N1 and the difference between N1s exceeds 35%.
  • FAC controls the entire side slip indication
• ”Speed, speed, speed!”
  
  • Given by Low Energy Warning
  • Flaps 2-F, below 2000 feet to 100 feet
  • Forewarns you what is coming?
  • Alpha Floor — liftoff to 100 feet on approach
• Windshear
  
  • Reactive
  • 3-5 seconds = 50-1300 ft / 1300-50 ft
  • Windshear on PFDs
• Flight Envelope Protections
  
  • Speed tape symbology
• Tail — controls the following functions
  
  • Rudder limiting
  • Alternate Law yaw
  • Turn coordination
  • Trim
  • Yaw damping

Question 10

NORMAL LAW

Describe the various BANK ANGLE PROTECTIONS

Answer 10

When handflying:

• Any bank angle up to 33°, the airplane will stay there if you release the stick.
• Bank angles in excess of 33°, the airplane will return to 33° if the stick is released.
• At 45°, the flight directors will disappear.
• At 40°, flight directors will come back.
• 67° is the max bank angle, which roughly corresponds with our 2.7g load factor limit.

Question 11

What yaw protections do we have in Normal Law?

Answer 11

• Yaw damping
• Turn coordinating

Question 12

What pitch protections do we have in Normal Law?

Answer 12

Nose up:

• Flaps 0-3: 30° decreasing to 25° as aircraft slows
• Flaps full: 25° decreasing to 20° as aircraft slows
• Flight director disappears at 25°, comes back at 22°

Nose down:

• 15° in all configurations
• Flight director disappears at 13°, comes back at 10°

Question 13

What AoA protections do we have in Normal Law?

Answer 13

• V_MAX, V_LS, α_PROT, α_MAX

Question 14

What load factor protections do we have in Normal Law?

Answer 14

• Clean: -1.0g to +2.5g
• “dirty”: -0g to +2.0g
• ALPHA FLOOR* “on FMA and EWD.”

Question 15

What speed protections do we have in Normal Law? (Vmax)

Answer 15

“BASN”

• Speed protection becomes active at V_MO+6
  
  • Bank 40° (reduced from 67°)
  • A/P disconnect
  • Seeks wings level
  • Nose up movement
• Speed will be limited to V_MO+16

Question 16

What bank protections do we have in Alternate Law?

Answer 16

None

Question 17

What yaw protections do we have in Alternate Law?

Answer 17

Yaw Damping only

Question 18

What pitch protections do we have in Alternate Law?

Answer 18

None

Question 19

What AoA protections do we have in Alternate Law?

Answer 19

Indicates V_LS and V_SW.

Question 20

What load protections do we have in Alternate Law?

Answer 20

Same as Normal Law:

• -1 to +2.5 g clean
• 0 to 2.0 g dirty

Question 21

What speed protections do we have in Alternate Law?

Answer 21

Varies - depends on what’s broken.

Question 22

What bank protections do we have in Direct Law?

Answer 22

None

Question 23

What yaw protections do we have in Direct Law?

Answer 23

Mechanical rudder

Question 24

What pitch protections do we have in Direct Law?

Answer 24

None

Question 25

What AoA protections do we have in Direct Law?

Answer 25

Indicates V_LS and V_SW.

Question 26

What load protections do we have in Direct Law?

Answer 26

None

Question 27

What speed protections do we have in Direct Law?

Answer 27

Aural overspeed