Flight Controls Flashcards
Describe roll control under normal conditions:
- Capt’s control wheel connected by cables to aileron PCUs
- F/O’s control wheel connected by cable to spoiler PCUs
- Capt & F/O control wheels linked by cable drive system
- Flight spoilers supplement ailerons at > 1.7 units control wheel movement
What happens if ailerons are jammed?
- Ailerons and Capt’s control wheel inop
- F/O uses spoilers for roll control
(If spoilers jammed, opposite occurs – Capt uses ailerons for roll control and F/O’s control wheel is inop – either way, a transfer mechanism allows use of unjammed controls by separating them from jammed controls)
What happens if a control column is jammed?
An override mechanism allows separation of columns to “break out” the unjammed control column
How are roll and pitch controlled with loss of both hydraulic systems?
Manual reversion (control cables assisted by balance tabs)
Describe the Mach Trim System:
Above Mach .615, the system automatically repositions the elevator feel + centering unit, which adjusts control column neutral position. This provides speed stability at higher Mach numbers.
What speed modes are available for main electric and autopilot stab trim?
- Flaps retracted Low speed trim
* Flaps extended High speed trim
If the stabilizer is trimmed to the end of its electrical trim limits, is additional trim available?
Yes – use manual trim
What speed modes are available for main electric and autopilot stab trim?
- Flaps retracted Low speed trim
* Flaps extended High speed trim
If the stabilizer is trimmed to the end of its electrical trim limits, is additional trim available?
Yes – use manual trim
What is the function of the control column actuated stabilizer trim cutout switches (not to be confused with pedestal-mounted STAB TRIM CUTOUT Switches or the STAB TRIM Override Switch)?
To stop stab trim operation when control column movement is opposite direction of trim movement
How can control column stab cutout trim switches be overridden (i.e. if trim stopped out of range)?
Place STAB TRIM Override Switch in OVRD
What is the function of the pedestal-mounted STAB TRIM CUTOUT Switches (MAIN ELECT and AUTOPILOT)?
To allow autopilot or main electric trim inputs to be disconnected from the stabilizer trim motor
Describe rudder control:
- Rudder pedals connected by cable to main + standby rudder PCUs
- Main rudder PCU powered by System A & B, but each system has its own input rod, control valve, and actuator.
- Force Fight Monitor (FFM) detects opposing pressure (force fight) between A & B actuators. If a force fight occurs, the FFM automatically opens the Standby Rudder S/O Valve and turns on the Standby Pump. This illuminates the STBY RUD ON Light, M/C and FLT CONT System Annun Lights.
- Standby rudder PCU powered by Standby Hydraulic System
- Above 135K, System A and B pressure within rudder PCU reduced by 25% each
Describe rudder control:
- Rudder pedals connected by cable to main + standby rudder PCUs
- Main rudder PCU powered by System A & B, but each system has its own input rod, control valve, and actuator.
- Force Fight Monitor (FFM) detects opposing pressure (force fight) between A & B actuators. If a force fight occurs, the FFM automatically opens the Standby Rudder S/O Valve and turns on the Standby Pump. This illuminates the STBY RUD ON Light, M/C and FLT CONT System Annun Lights.
- Standby rudder PCU powered by Standby Hydraulic System
- Above 135K, System A and B pressure within rudder PCU reduced by 25% each
When is hydraulic pressure to the rudder reduced?
Above 135K
When the YAW DAMPER Switch is placed ON, what happens?
- Main YD engaged to main rudder PCU if FLT CONTROL B Switch ON.
- Stby YD engaged to stby rudder PCU if FLT CONTROL A and B Switches in STBY RUD.
What is displayed by the YAW DAMPER Indicator on the main panel (installed only on 3AA-3FK)?
Main yaw damper movement of the rudder
What happens to the yaw damper if System B (its normal power source) fails?
YAW DAMPER Switch remains ON (w/ YAW DAMPER Light not illuminated), but no yaw damper is available (main or stby). However, if both System A and B lost, Standby System can power standby yaw damper (if YAW DAMPER Switch ON).