Hydraulic Systems and Autopilot Quiz

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Questions and Answers

Which Hydraulic System(s) normally power the primary flight controls? [FCOM 9.20.1]

Hydraulic System A

Hydraulic System A and B (correct)

Hydraulic System B

What powers each primary flight control surface with the loss of both Hydraulic Systems A and B (manual reversion)? [FCTM 8.46]

Ailerons: Mechanically through cables (correct)

Elevator: Mechanically through cables (correct)

Rudder: Standby Hydraulic System (correct)

None of the Above

With the loss of Hydraulic System B, how are the Leading Edge (LE) Flaps and Slats and the Trailing Edge (TE) Flaps operated? [FCOM 9.20.1]

Trailing Edge (TE) Flaps: Electrically (correct)

Leading Edge (LE) Flaps and Slats: Standby Hydraulic System (correct)

With a jammed or restricted Aileron System, how is roll controlled? [FCOM 9.20.3]

Force applied to the First Officer's control wheel provides roll control from the spoilers. Signup and view all the answers

Why is aileron trim prohibited with the autopilot engaged? [FCOM 9.20.3]

With the autopilot engaged, aileron trim is not reflected in the control wheel position Signup and view all the answers

How many degrees of control wheel displacement initiates Flight Spoiler deflection? [FCOM 9.20.4]

More than 10° (approximately) Signup and view all the answers

What does an illuminated FEEL DIFF PRESS light indicate? [FCOM 9.10.3, 9.20.7]

Caused by either Hydraulic System A or B loss or the Elevator Feel Pitot System failure Signup and view all the answers

If either the Captain's or First Officer's control column is jammed, how would you regain elevator control? [FCOM 9.20.6]

Applying force against the jam will breakout either the Captain's or First Officer's control column Signup and view all the answers

When would you use the Elevator Jam Landing Assist system? [FCOM 9.20.6]

When there is a jam in the aft elevator control mechanism Signup and view all the answers

How does the Elevator Jam Landing Assist system aid when a landing is made with a jammed elevator? [FCOM 9.20.6, 9.20.7]

A push on the control column causes the spoilers to extend farther, increasing the descent rate Signup and view all the answers

How do you activate the Elevator Jam Landing Assist system? [FCOM 9.20.6]

Actual flap position must be 1 or greater and Signup and view all the answers

How is stabilizer trim accomplished? [FCOM 9.20.8, 9.20.9]

With the autopilot engaged, stabilizer trim is accomplished through the autopilot stabilizer trim circuit Signup and view all the answers

When is the Autopilot Trim or Main Electric Stabilizer Trim active in the high speed mode and low speed mode? [FCOM 9.20.8]

High Speed when Flaps are extended Signup and view all the answers

What is the purpose of the STAB TRIM Cutout (PRI and B/U) switches on the Control Stand? [FCOM 9.20.8]

Autopilot Trim Signup and view all the answers

If the STAB TRIM Cutout switches have been set to CUTOUT, how would you trim the stabilizer? [FCOM 9.20.9]

Manually trim by rotating the stabilizer trim wheel. Signup and view all the answers

What is the purpose of the Control Column Actuated Stabilizer Trim Cutout switches? [FCOM 9.20.8]

Aft control column movement does not affect MCAS nose down trim commands Signup and view all the answers

What is the purpose of the Flight Control Computer (FCC) software column cutout function? [FCOM 9.20.8]

Adds a layer of redundancy to mitigate a latent failure of the Control Column Actuated Stabilizer Trim Cutout switches Signup and view all the answers

What is the purpose of the STAB TRIM switch on the aft electronics panel? [FCOM 9.20.8]

When positioned to OVRD, allows operation of the Main Electric Stabilizer Trim regardless of control column position Signup and view all the answers

What will occur if you attempt to takeoff with the stabilizer trim out of the green band? [FCOM 9.20.9]

An intermittent horn sounds (Takeoff Warning horn) Signup and view all the answers

What does the Speed Trim System (STS) provide? [FCOM 9.20.9]

Speed and pitch stability augmentation Signup and view all the answers

Will the Speed Trim System (STS) operate when the autopilot is engaged? [FCOM 9.20.9]

False Signup and view all the answers

What does Speed Trim function accomplish? [FCOM 9.20.10]

Return the airplane to a trimmed speed by commanding the stabilizer in a direction opposite the speed change Signup and view all the answers

What are the conditions for Speed Trim function to operate? [FCOM 9.20.10]

10 seconds after takeoff Signup and view all the answers

What speed does the Speed Trim function control the stabilizer trim motor? [FCOM 9.20.10]

High rate with Flaps extended Signup and view all the answers

What does the Maneuvering Characteristics Augmentation System (MCAS) function accomplish? [FCOM 9.20.11]

MCAS is a pitch stability augmentation function designed to operate at elevated Angles Of Attack (AOAS) Signup and view all the answers

What are the conditions for Maneuvering Characteristics Augmentation System (MCAS) function to operate? [FCOM 9.20.11]

AOA above threshold Signup and view all the answers

Will MCAS activate with an autopilot engaged?

False Signup and view all the answers

What speed does the Maneuvering Characteristics Augmentation System (MCAS) function control the stabilizer trim motor? [FCOM 9.20.11]

High rate Signup and view all the answers

Where does the Flight Control Computer (FCC) get its data to activate MCAS? [FCOM 9.20.11]

Both AOA vanes Signup and view all the answers

How can MCAS stabilizer operation be inhibited and reversed? [FCOM 9.20.11]

By using pilot Main Electric Stabilizer Trim switches Signup and view all the answers

After Main Electric Stabilizer Trim is used to inhibit Speed Trim or MCAS, how long is the delay before Speed Trim or MCAS will operate if needed again? [FCOM 9.20.10, 9.20.11]

Inhibited for 5 seconds Signup and view all the answers

Why does the MCAS function contain logic that limits the amount of nose down stabilizer trim movement? [FCOM 9.20.11]

To preserve elevator authority for pitch control Signup and view all the answers

What occurs when MCAS has reached its command limit logic nose down stabilizer trim limit? [FCOM 9.20.11]

Speed Trim System (Speed Trim function and MCAS function) is inhibited for the remainder of the flight Signup and view all the answers

What causes the SPEED TRIM FAIL light to illuminate and remain illuminated after a FLT CONT Master Caution is reset? [FCOM 9.10.3, 9.20.10]

Failure in the Speed Trim System (Speed Trim function or MCAS function) Signup and view all the answers

What if you only get the FLT CONTROL Master Caution on RECALL and see this light, and the light extinguishes when the Master Caution system is reset? Would you perform the QRH Non-Normal Checklist in this scenario? [FCOM 9.10.3]

No Signup and view all the answers

Can the pilot override the Speed Trim System (Speed Trim function and MCAS function) nose up or nose down stabilizer trim commands?

Exception: does not interrupt MCAS nose down stab trim commands Signup and view all the answers

What is the purpose of the Elevator Feel Shift (EFS) module? [FCOM 9.20.13]

Increases Hydraulic System A pressure to the Elevator Feel and Centering Unit during a stall Signup and view all the answers

What protection do the Flight Control Computers (FCCs) provide with regards to stall identification? [FCOM 9.20.13]

The FCCs continuously monitor each other's stabilizer trim commands, autopilot trim commands, and Control Wheel Steering (CWS) trim commands are stopped and inhibited for the remainder of the flight for that FCC. Signup and view all the answers

What does the Autopilot Elevator Monitor protect against? [FCOM 9.20.13]

Erroneous elevator commands that can result in erroneous autopilot stabilizer trim commands Signup and view all the answers

What does the Stabilizer Cross-FCC Trim Monitor protect against? [FCOM 9.20.14]

Erroneous stabilizer trim commands Signup and view all the answers

What does illumination of a STAB OUT OF TRIM light indicate? [FCOM 4.10.20]

In-flight Signup and view all the answers

What does illumination of a FLT CONTROL LOW PRESSURE light indicate? [FCOM 9.10.2]

Low Hydraulic System (A or B) pressure to ailerons, rudder and elevator Signup and view all the answers

How can the standby rudder system be pressurized? [FCOM 9.10.1, 9.20.16]

By either Flight Control switch in the STBY RUD position or Signup and view all the answers

What does the illumination of the STBY RUD ON light indicate? [FCOM 9.10.2]

Standby rudder system is commanded on to pressurize the standby rudder power control unit Signup and view all the answers

What is the purpose of the Force Fight Monitor (FFM) on the Main Rudder PCU? [FCOM 9.20.15]

This may occur if either Hydraulic System A or B input is jammed or disconnected Signup and view all the answers

How would you know that the Force Fight Monitor (FFM) has sensed a jammed rudder? [FCOM 9.20.15]

The FFM output is used to automatically turn on the Standby Hydraulic pump and open the standby rudder shutoff valve to pressurize the standby rudder PCU Signup and view all the answers

What does the Rudder Trim control switch do? [FCOM 9.20.16]

Electrically repositions the Rudder Feel and Centering Unit and displaces the Rudder pedals Signup and view all the answers

Will the rudder trim operate with the autopilot engaged?

True Signup and view all the answers

How many yaw dampers does the yaw damper system consist of? [FCOM 9.20.16]

Main Yaw Damper Signup and view all the answers

What protections does the yaw damper provide? [FCOM 9.20.16]

Gust damping Signup and view all the answers

When will the Yaw Damper switch automatically move to the OFF position? [FCOM 9.20.16]

SMYD senses that the yaw damper does not respond to a command or Signup and view all the answers

When is the Standby Yaw Damper available? [FCOM 9.20.16]

and the YAW DAMPER switch is reset to ON Signup and view all the answers

The loss of Hydraulic Systems A and B will render which spoiler panels inoperative? [FCOM 9.20.21]

All Spoiler panels (Flight and Ground spoilers) Signup and view all the answers

What happens when electrical power is lost to the Spoilers Control Electronics (SCE) Unit? [FCOM 9.20.18]

All spoilers are inoperative and will retract if extended Signup and view all the answers

Which Flight Control switch(es) are used for maintenance purposes only? [FCOM 9.10.1, 9.10.2]

SPOILER A and B Signup and view all the answers

During landing or rejected takeoff, when would the auto speedbrake system operate if the speedbrake lever was in the down position? [FCOM 9.20.20]

Both thrust levers are retarded to IDLE Signup and view all the answers

What does illumination of a SPEED BRAKE DO NOT ARM light indicate? [FCOM 9.10.9]

Fault within the auto speedbrake system Signup and view all the answers

When does the SPEED BRAKES EXTENDED light illuminate? [FCOM 9.20.18]

In-flight, the light illuminates to warn the crew that the speedbrakes are extended while in the landing configuration or below 800 feet AGL Signup and view all the answers

Study Notes

Hydraulic Systems and Flight Controls

Hydraulic System A and B power primary flight controls
Manual reversion available for ailerons, elevators, and rudder if both hydraulic systems fail
Leading Edge (LE) Flaps and Slats use Standby Hydraulic System, Trailing Edge (TE) Flaps use electrical system when system B fails
Jammed aileron system: roll is controlled by applying force to the First Officer's control wheel through spoilers
Jammed spoiler system: roll is controlled by applying force to the Captain's control wheel using the ailerons

Autopilot and Trim

Aileron trim is prohibited when autopilot is engaged
Autopilot overpowers trim, maintaining control wheel position for heading/track
More than 10 degrees of control wheel displacement initiates spoiler deflection
Illuminated FEEL DIFF PRESS light indicates excessive differential pressure likely caused by hydraulic system A or B failure, or an Elevator Feel Pitot System failure

Elevator Jam Landing Assist

Used when aft elevator control mechanism is jammed
During approach and landing, the Elevator Jam Landing Assist system uses spoilers for descent rate changes

Autopilot

Stabilizer trim is accomplished through autopilot stabilizer trim circuit during autopilot operation, and main electric stabilizer trim circuits for manual operation.
Autopilot trim or main electric stabilizer trim active: high speed (flaps extended), low speed (flaps retracted)
Stabilizer trim cutoff: disables autopilot trim and main electric stabilizer trim for manual trim
The control column actuated stabilizer trim cutout: interrupts operation of main electric stabilizer trim, autopilot trim and speed trim function
The FCC software column cutout: redundancy for cutout of control column activated stabilizer trim cutout
STAB TRIM switch: enables operation of main electric stabilizer regardless of control column position

Speed Trim System

Provides speed and pitch stability augmentation, the function is aided by MCAS.
It operates when the autopilot is disengaged.

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Description

Test your knowledge on hydraulic systems and flight controls, including how hydraulic failures affect primary flight controls and the operation of manual reversion systems. This quiz also covers autopilot functions, trim issues, and how to manage control displacement during flight. Perfect for aviation enthusiasts and professionals alike!