01/18/23 Flight Controls

Question 1

Which hydraulic system(s) can power all primary flight controls?

Answer 1

Systems A and B.

Primary Flight Controls are powered by redundant hydraulic sources, System A and System B. Either hydraulic system can operate all of the Primary Flight Controls.

Question 2

What are the secondary flight controls?

Answer 2

include high lift devices, drag devices, and roll augmentation.

High lift devices
-Trailing Edge (TE) Flaps
-Leading Edge Flaps and Leading Edge Slats.

Drag - Spoilers symmetrically (speed brakes)

Roll augmentation - Spoilers

Question 3

The Trailing Edge Flaps and Leading Edge Devices are normally powered by which system?

Answer 3

Hydraulic System B

Question 4

What happens when placing a FLT CONTROL switch to STBY RUD?

Answer 4

• activates the Standby Hydraulic System
• opens the Standby Rudder Shutoff Valve (allowing Standby Hydraulic System pressure to the Standby Rudder PCU)

Question 5

How are the Rudder, Ailerons, and Elevators operated in manual reversion?

Answer 5

Ailerons, Elevators operated manually. The rudder may be operated with the Standby Hydraulic System

During Manual Reversion (loss of both Hydraulic Systems A and B), the ailerons and elevators are operated manually. When hydraulic pressure is not provided to the Aileron or Elevator PCUs, mechanical throughput is provided in the PCU out to the normal mechanical path to the Ailerons and/or Elevators. The rudder may be operated by the Standby Hydraulic System if System A and System B pressure is not available.

NOTE: There are no provisions for manual operation of the rudder.

Question 6

How is roll controlled with jammed ailerons?

Answer 6

Flight Spoilers, through the First Officers control wheel.

If the Aileron Control System is jammed, force applied to the First Officer’s control wheel actuates the Aileron Transfer Mechanism and provides roll control using the Flight Spoilers. The ailerons and the Captain’s control wheel are inoperative.

Question 7

How would a single channel failure of the Mach Trim systems be indicated?

Answer 7

During Master Caution Recall the MACH TRIM FAIL light illuminates and extinguishes when the Master Caution System is reset.

Question 8

How is the horizontal Stabilizer Trim normally operated? Is there an alternative way?

Answer 8

Either by the autopilot or the Stabilizer Trim Switches.

It may also be positioned by manually rotating the Stabilizer Trim Wheels.

Question 9

Can the Speed Trim System be overridden? If so, how?

Answer 9

Yes,

• actuation of the Control Wheel Trim Switches (inhibits further Speed Trim operation for 5 seconds)
• manual rotation of either Stabilizer Trim Wheel

Question 10

Which system(s) help in identifying and controlling stalls?

Answer 10

Yaw Damper, the Elevator Feel Shift (EFS) Module and the Speed Trim System

Question 11

What factors are used by the Stall Management Yaw Damper computers to determine when a stall warning is required?

Answer 11

• Angle of Attack Sensor outputs
• ADIRU outputs
• anti-ice controls
• wing configurations
• air/ground sensing
• thrust
• FMC outputs
• Mach compensation

Question 12

What is required to activate the Main Yaw Damper?

Answer 12

• Hydraulic System B pressure
• the B FLT CONTROL switch in the ON (guarded) position, and
• the SMYD computers to provide continuous system monitoring

Question 13

When will the SPEEDBRAKES EXTENDED (amber) light illuminate?

Answer 13

• in flight, with the SPEED BRAKE lever beyond the ARMED position, and:
  • TE Flaps extended more than Flaps 10, or
  • radio altitude less than 800 ft
• on the ground, with the SPEED BRAKE lever in the DOWN detent and hydraulic pressure is sensed by a pressure switch (750 psi) in the Ground Spoiler Interlock
  Valve (ground spoilers may not be stowed)

NOTE: On the ground, the SPEEDBRAKES EXTENDED light does not illuminate when Hydraulic System A pressure is less than 750 psi.

Question 14

What would cause the Speed Brake lever to automatically stow after deployment on landing or RTO?

Answer 14

if either thrust lever is advanced, the SPEED BRAKE lever automatically moves to the DOWN detent and all spoiler panels retract.

NOTE: The spoiler panels may also be retracted by manually moving the SPEED BRAKE lever to the DOWN detent.

Question 15

What does the LE FLAPS TRANSIT (amber) light below the Trailing Edge Flaps indicate?

Answer 15

• any LE device in transit
• any LE device not in programmed position with respect to TE flaps
• a LE uncommanded motion condition exists (2 or more LE flaps or slats have moved away from their commanded position)
• during alternate flap extension until LE devices are fully extended and TE Flaps reach Flaps 15

NOTE: The LE FLAPS TRANSIT light is inhibited during autoslat operation in flight.

Question 16

What is the Flap Load Relief system?

Answer 16

It protects the trailing edge flaps from excessive air loads.

Captain’s indicated airspeed is too high for the selected flap setting, flap load relief activates and retracts the TE flaps to the next lower setting below the selected Flap Lever position. (Flap lever doesn’t move)

Question 17

When using the Alternate Flaps UP/DOWN switch, how can the Leading Edge Devices and Trailing Edge Flaps be operated?

Answer 17

LE devices are fully extended when the switch is selected down. They cannot be retracted.

TE Flaps controls an electric motor that extends or retracts the TE Flaps. The switch must be held DOWN until the flaps reach the desired position. The UP position is detected and will retract the TE Flaps

Question 18

Are there any protections during an Alternate Flaps extension?

Answer 18

No,

During alternate extension, the following protective systems are not available:
• flap load relief
• asymmetry protection
• skew protection
• autoslat operation
• LED depressurization valve
• PTU operation
• Leading Edge Uncommanded Motion Protection