Flight Controls

Question 1

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

Answer 1

Aileron, elevator, and rudder are powered by system A and B. Either system can operate all of the primary flight controls

Question 2

What are the secondary flight controls?

Answer 2

High lift devices
-Trailing Edge (TE) flaps
-Leading Edge Devices (LEDs)
—inboard LED flaps, outboard LED slats
-Hyd Sys B
-backup: TE elec motor, LED Stby Hyd sys

Dragdevices and Roll augmentation
-Flight spoilers
—symmetric deploy for drag
—A-symmetric for roll
-Hyd Sys A and B
-Ground spoilers
—Hyd Sys A

Question 3

Trailing edge flaps and leading edge devices are normally powered by which system?

Answer 3

system B

Question 4

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

Answer 4

LOW PRESSURE (Amber) (Sys A or B)
Light extinguishes.

Standby Hyd LOW PRESSURE (Amber) light armed

STBY RUD ON (Amber) illuminated cuz Stby elec Hyd pump on.

Activates standby Hyd system

Opens standby rudder SOV allowing Standby Hudraulic System pressure to the Standby Rudder PCU

• placing system B to Stby rud will release yaw damper to off

Question 5

How are the rudder, ailerons, and elevators operated in manual reversion?

Answer 5

(Loss of both A and B systems)

Ailerons/Elevator Operated manually
Mechanical throughput in PCU via cable

Rudder operated by standby Hyd sustem

Question 6

How is roll controlled with jammed ailerons?

Answer 6

Aileron transfer mechanism
-Aileron system jammed, FO control wheel actuates flight spoilers. Ailerons and Captain control wheel inop
-Spoiler system jammed, Captain control wheel actuates ailerons. Spoilers and FO control wheel inop

*using this system requires approx 117 lbs control force on operative control wheel

Question 7

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

Answer 7

MACH TRIM FAIL (amber) light
-Master Caution Recall (single channel)

Question 8

How is the horizontal stabilizer trim normally operated? Is there an alternative way?

Answer 8

Single motor via either control wheel Stab Trim Switch or autopilot trim

Manually by Stabilizer Trim Wheels

Question 9

Can the speed trim system be overridden? If so, how?

Answer 9

System returns aircraft to trimmed speed. Mostly operates on takeoff, climb, and go-around

Yes, by control wheel electric trim switches (inhibits for 5 sec). And manual rotation of trim wheel

Does not operate with autopilot engaged.

Question 10

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

Answer 10

Yaw damper
Elevator Feel Shift (EFS) Module
Speed Trim System
Auto slats

SMYD (stall management yaw damper) reduces yaw damper command rudder movement

SMYDs command EFS to increase control forces up to 2x normal

Speed Trim nose down as needed. Active until trim greater than 9 units

Question 11

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

Answer 11

AOA sensor outputs
ADIRU outputs
Anti-ice controls
Wing configurations
Air/ground sensing
Thrust
FMC outputs
Mach compensation

2 independent SMYDs

Question 12

What is required to activate the Main Yaw Damper?

Answer 12

-Hydraulic system B pressure
-B FLT CONTROL switch to ON (guarded)
-at least one IRS switch on
-the SMYDs to provide continuous monitoring

SMYD 1 main yaw damp/turn coordination
SMYD 2 WTRIS (wheel to rudder interconnect system) and Stby operations

SMYD 2 monitors 1. If don’t agree, yaw damp disengages. If one SMYD fails, other takes over.

Yaw damp moves to OFF
-SMYD Sys fault
-SMYD senses yaw damp not respond
-B FLT CONTROL switch to OFF or STBY RUD
—both FLT CONTROL switches to STBY RUD, yaw damp can be reset ON

Question 13

When will the the SPEEDBRAKES EXTENDED (amber) light illuminate?

Answer 13

In flight
-speed brake lever beyond armed position, and
—TE Flaps more than 10, or
—RA less than 800 ft

On ground with speed brake lever in DOWN detent and hydraulic pressure sensed by pressure switch (750 psi) in Ground Spoiler Interlock Valve (ground spoilers may not be stowed)

*does not illuminate on ground when Hyd A less than 750 psi

Question 14

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

Answer 14

Either thrust lever is advanced

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

-LE uncommanded motion (2 or more LE flaps or slats moved)

-During alternate flap extension until LE are fully extended and TE reach 15

Question 16

What is the flap load relief system?

Answer 16

Protects TE flaps from excessive air loads.
-left Captains ADIRU (airspeed)

Retracts TE flaps to next lower setting of airspeed too high.

Operative at flaps 10, 15, 25, 30, and 40

*flap handle doesn’t move but position indicator shows flap retraction and re-extension.

*selecting flaps 40 ensures at least flap 30 for landing.

Question 17

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

Answer 17

If Hydraulic system B fails, alternate method of extending LE devices and extending/retracting TE Flaps
-TE operated by electric motor
-LED can fully extend (only) Stby Hyd system

ALTERNATE FLAPS master switch to ARM
ALTERNATE FLAPS position switch to up or down

Question 18

Are there any protections during Alternate Flap extension?

Answer 18

No, the following protective systems not available:
-flap load relief
-asymmetry protection
-skew protection
-autoslat operation
-LED depressurization valve
-PTU operation
-Leading Edge Uncommanded motion