Flight Controls Flashcards
The primary flight control system consists of:
- ailerons and multi-function spoilers
- elevators
- rudder
The secondary flight control system consists of:
- horizontal stabilizer
- flaps and slats
- multi-function spoilers used as speed brakes or ground spoilers
- dedicated ground spoilers
The primary flight control electronics are generally comprised of two parts:
- the Primary Actuator Control Electronics (P-ACE)
- the Flight Control Module (FCM)
Flight Control Mode Button PUSH IN/PUSH OUT
IN - direct mode
OUT - normal mode
Name the nine Actuator Control Electronics (ACEs)
- three primary ACEs (P-ACE)
- two slat/flap ACEs (SF-ACE)
- one horizontal stabilizer ACE (HS-ACE)
- three spoiler ACEs (S-ACE)
How many flight control modules (FCM)?
four
How many channels does each ACE have?
two, one active and one standby
Location of P-ACEs
fwd ebay - 2
aft ebay - 1
Location of SF-ACEs
middle ebay
Location of HS-ACE
aft ebay
What do the FCMs do?
provide software based assistance to the P-ACE by providing higher level function augmentation to pilot inputs
FCM location
FCM 1 and 2 - MAU 1
FCM 3 and 4 - MAU 3
Name the higher level functions that the FCM provides in “normal mode”
- elevator control laws w/ airspeed
- auto thrust compensation with elevator
- mach trim and autopilot trim
- AOA limiting with elevator offset
- rudder airspeed gain scheduling and stroke limiting
- yaw damper and turn coordination via AFCS
- rudder flight authority
- roll spoiler scheduling and speed brake deployment
- automatic spoiler deployment at high mach number
- configuration change compensation with horizontal stabilizer
Describe direct mode
FCM is removed from control loop because of loss of data or multiple failures in both ACEs
What is the CAN BUS
Controller Area Network; communication link between the FCMs and the P-ACE units
The following systems provide data to the flight control system:
- smart probes and Air Data Application modules
- IRS
- Proximity Sensor Electronic Modules (weight on wheels)
- Brake Control Modules
- FADEC provides thrust lever angle
Describe the Fly By Wire Backup system
a dedicated backup battery with internal heater keeps elevator and rudder actuators operating for at least 15 minutes, charged by DC ESS 3
Describe the pitch system components
- electro-hydraulic commanded elevators
- electro-mechanical horizontal stabilizer
How many elevator PCUs
four, operate on active/standby mode alternating every time elevator system is powered up
Which hydraulic system power which elevator PCU
1 - left outboard
2 - left and right inboard
3 - right outboard
What happens during an elevator jam
if jam in one elevator actuator, respective elevator surface remains fixed in position, pilot controls remaining elevator
Elevator/Rudder Flight Control Panel Button
cycles between normal or direct mode and cycles active and standby PCUs
Describe the Elevator Thrust Compensation Function
helps reduce pilot workload by applying elevator commands to reduce pitching moment by increasing or decreasing engine thrust
Describe the elevator Artificial Feel Units
provide the feel and centering force for the control columns, consist of pre-loaded springs