Hydraulic Systems and Autopilot Controls

Hydraulic System A and B normally power the primary flight controls, including the ailerons, elevator, and rudder. This ensures smooth and reliable control of these surfaces during flight.

With the loss of both System A and B, the ailerons and elevator revert to mechanical control through cables, while the rudder is powered by the Standby Hydraulic System. This provides a backup mechanism for controlling the aircraft in case of hydraulic failure.

With only System B lost, the Leading Edge Flaps and Slats are controlled by the Standby Hydraulic System, while the Trailing Edge Flaps are controlled electrically. This ensures that the aircraft still has some control over its lift and drag even with a damaged hydraulic system.

Force applied to the First Officer's control wheel provides roll control through the spoilers, allowing the aircraft to maintain its wing level despite a jammed or restricted aileron system. This is a backup method to control roll when the ailerons are malfunctioning.

Force applied to the Captain's control wheel provides roll control through the ailerons, providing a backup method when the spoilers are jammed or restricted. This allows the pilot to maintain roll control even with a malfunctioning spoiler system.

Aileron trim should be avoided when the autopilot is engaged because it can cause a rolling movement when the autopilot is disengaged. This is because the autopilot overrides the trim setting, leading to a discrepancy between the control wheel position and the actual trim setting.

Flight Spoilers deflect when the control wheel displacement exceeds approximately 10 degrees. This provides a safety mechanism by reducing lift and increasing drag, aiding in deceleration and preventing excessive speed during a descent or landing.

A function designed to enhance pitch stability during flight at high angles of attack (AOA). It increases control column forces by commanding the stabilizer to move in the nose-down direction, thereby preventing excessive pitch-up during takeoff and climb.

When positioned to OVRD, allows the pilot to adjust the stabilizer trim manually, independent of the control column position.

A system that enhances both speed and pitch stability during flight. It operates via two functions: Speed Trim and MCAS.

A feature that improves flight characteristics during low gross weight, aft center of gravity, and high thrust conditions. It helps maintain trimmed speed by commanding the stabilizer opposite the speed change.

Provides speed and pitch stability augmentation during flight.

Will sound an intermittent horn and illuminate the TAKEOFF CONFIG light if you attempt to take off with the stabilizer trim out of the green band.

Conditions where the Speed Trim function is active: up to Mach 0.68, 10 seconds after takeoff, 5 seconds after releasing the main electric stabilizer trim switches, autopilot is not engaged, and a trim requirement is sensed.

A built-in redundancy feature that mitigates failure of the Control Column Actuated Stabilizer Trim Cutout switches.

The Speed Trim function controls the stabilizer trim motor at a high rate with flaps extended and a low rate with flaps retracted.

The Flight Control Computers (FCCs) constantly monitor each other's stabilizer trim commands. If a discrepancy is detected, the faulty FCC is immediately disabled, preventing unintentional stabilizer movements.

The Autopilot Elevator Monitor detects and prevents erroneous elevator commands from reaching the autopilot system, which could cause incorrect stabilizer trim adjustments and destabilize the aircraft.

The Stabilizer Cross-FCC Trim Monitor safeguards against incorrect stabilizer trim commands from the Flight Control Computers ensuring the stabilizer works correctly.

The STAB OUT OF TRIM light alerts the crew when the autopilot is not adjusting the stabilizer correctly. It indicates an issue with either the autopilot or one of the Flight Control Computers. The light also illuminates on the ground after landing if a Flight Control Computer is malfunctioning.

The FLT CONTROL LOW PRESSURE light signals low hydraulic pressure in either system A or B affecting the ailerons, rudder, and elevator.

The standby rudder system can be activated manually by setting the Flight Control switch to STBY RUD. It can also activate automatically during takeoff, landing, or when the Force Fight Monitor senses a jammed rudder.

The STBY RUD ON light indicates that the standby rudder system is powered up, ready to take over the rudder's control.

The Force Fight Monitor (FFM) on the Main Rudder PCU detects when there's a conflict between the hydraulic systems controlling the rudder, signaling a potential jam.

The FFM will detect a jammed rudder by sensing opposing forces from the hydraulic actuators, indicating a potential jam. This signals the need to investigate and manage the issue.

The Standby Rudder system is automatically engaged when the FFM output is used.

It electrically repositions the Rudder Feel and Centering Unit, which in turn displaces the Rudder pedals.

Yes, rudder trim can be controlled with the autopilot engaged.

The yaw damper system consists of both a main yaw damper and a standby yaw damper.

The Yaw Damper system provides protection against Dutch roll, gust damping, and turn coordination.

The yaw damper switch will automatically move to OFF when SMYD detects a yaw damper system fault, lack of response to commands, or when the B FLT CONTROL switch is moved to OFF or STBY RUD.

The Standby Yaw Damper is available during manual reversion (loss of both Hydraulic System A and B) with both FLT CONTROL switches set to STBY RUD and the YAW DAMPER switch reset to ON.

All spoiler panels, both flight and ground spoilers, become inoperative with a loss of Hydraulic Systems A and B.

All spoilers become inoperative and retract if extended when electrical power to the Spoilers Control Electronics (SCE) Unit is lost.

The SPOILER A and B switches are used for maintenance purposes only, not for normal flight operations.

The flap load relief function protects the trailing edge flaps from excessive air loads by automatically retracting and re-extending the flaps one setting lower than the selected flap setting. This prevents damage to the flaps during high load conditions.

The Leading Edge (LE) FLAPS TRANSIT (amber) light indicates that one or more LE devices (flaps or slats) are in transition or not in their programmed position relative to the trailing edge flaps. It could also be triggered by two or more LE devices moving from their commanded position.

Normal landing flap settings are Flaps 15, 30, and 40. Flap 15 is normally limited to airports where approach climb performance is a factor, as it provides a balance between lift and drag.

The AUTO SLAT FAIL light, illuminated during the Master Caution RECALL, indicates a failure of a single Stall Management Yaw Damper (SMYD). This failure does not warrant the execution of the QRH Non-normal checklist, as the system is redundant, and the remaining SMYD can still operate effectively.

With Hydraulic System B failure, the Leading Edge (LE) Flaps & Slats can only extend (using the Standby Hydraulic system), while the Trailing Edge (TE) Flaps extend and retract using an electric motor. This provides a backup system for flap control.