Flight Controls Flashcards
Components
- 3 computers: 2 Flight Control Computers (FCCs) and Backup Flight Control Unit (BFCU) - - 16 actuators: 9 Hydraulic Actuators (HAs) and 7 Electric Backup Hydraulic Actuators (EBHAs) - 16 Remote Electronics Units (REUs)
- Horizontal Stab Control Unit (HSCU)
- Horizontal Stab Trim Actuator (HSTA)
- 2 Flight Control System (FCS) batteries: Electric Backup Hydraulic Actuator (EBHA) battery and Uninterruptable Power Supply (UPS) battery
- Flap Electronic Control Unit (FECU)
- GVIII uses fly-by-wire technology. How does this work?
Pilot inputs are read by a computer that in turn decides how to move control surfaces to best achieve what the pilot wants.
- How is trim accomplished?
Pitch and roll trim is accomplished by actuating switch mounted on sidestick; pedestal mounted PITCH TRIM switch is also used to control pitch.
- What’s the purpose of A/P DISC switch?
It disengages autopilot and stops runaway trim in all three axes.
- What’s the function of FLT CTRL RESET switch?
Used to reset flight control computers, sidesticks, and control surface actuators when directed by checklist.
- What effect does loss of one hydraulic system have on flight controls?
Loss of one spoiler pair.
- What are control laws?
Software in FCCs that translate electrical commands from cockpit control sensors and aircraft motion sensors (inertial/air data) into flight control surface commands.
- How many computers control the fly-by-wire flight control system?
Three (3) computers: two (2) flight control computers for normal operation and Backup Flight Control Unit in case both flight control computers fail.
- What’s the minimum number of FCC channels that can command all flight control surfaces on the aircraft.
One
- What’s the purpose of Backup Flight Control Unit (BFCU)?
It’s designed to provide what Gulfstream calls “get home capability” if both primary FCCs fail.
- What happens once the BFCU becomes active?
It communicates directly with EBHA remote electronics units (REUs) on separate backup data buses, and is active for duration of flight.
- Describe Electric Backup Hydraulic Actuator (EBHA).
It’s a special actuator with self-contained electric motor/pump and hydraulic reservoir.
- What type of sensor input is provided to FCCs?
Input from IRSs, AHRS, ADSs and radio altimeters.
- Describe AOA limiting feature.
In this mode, full stick input commands maximum nose angle-of-attack of 0.95.
- Which mode protects from surface flutter and separation that would occur greater than Vdive speed?
High speed protection
- What’s the auto-retract feature?
It retracts speed brakes at high power settings.
- What enhanced rudder feature occurs automatically following engine failure?
Application of rudder counters uncommanded thrust asymmetry.
- Name the four (4) flight control modes.
Normal, alternate, direct, and backup.
- When would flight control mode change from normal to alternate?
Loss of multiple air data or inertial sensors; may also revert to alternate mode if FCCs lose communication with HSCU.
- What happens if all four (4) FCC channels are invalid?
Flight control system reverts to direct mode.