Flight controls Flashcards
What flight controls does the FBW system control?
All primary and secondary flight controls with exceptions from flaps and slats.
What are the two FBW modes?
Normal or direct mode
How many channels does the FBW system consist of?
Three.
What is the primary source of power for the FBW system?
The three different channels are powered by the DC busses.
What is the secondary source of power for the FBW system?
The PMAG.
What are
IIM
PFCC
REU
AFCU
?
IMM = Inceptor Interface Module
PFCC = Primary Flight Control Computer
REU = Remote Electronic Unit
AFCU = Alternate Flight Control Unit
What is the function of the IIM’s?
Receives inputs from flight deck and transmits to PFCC’s.
What is the function of he PFCC’s?
They are responsible for the operation of the FBW system and associated functions. hey receive signals from the IIM’sor AFCS/FDS och commands movement of the flight control surfaces.
They also provide flight envelope and structural protection.
How many PFCC’s controls the FBW system?
One at a time.
PFCC’s receive data input from?
IRS’s and ADSP’s
What is the function of the REU’s?
They transmit commands to the PCU’s from the PFCC.
Two REU’s transmit commands to the horizontal stabilizer’s electric trim motors.
What happens if a PFCC fails?
The REU’s receive signals directly from the IIM’s.
This is called REU direct mode.
What happens if the FBW system i severly degraded?
The AFCU bypasses the REU’s.
There will be direct interface between flight deck controls and stabilizer, and ne PCU in each aileron, elevator and rudder. This is AFCU direct mode.
How does speed stability use pitch in normal mode?
It uses pitch to maintain selected trim speed.
What system controls the auto stabilizer trim mode?
The FBW system.
At what bank angle does the crew need to compensate with pitch during a turn?
Above 33 degree bank.
Describe the Nose Landing Gear Loading function.
On ground, when TL above 24 deg, causes elevetor to deflect to a nose down position.
It’s active up to 80 KTS and inactive at 90 KTS.
When does ground mode occur?
It’s dictated by a combination of RA, weight on wheels and wheel speed.
When is ground to air transition complete?
3 seconds after aircraft is airborne.
How are airspeed and rudder travel related?
Higher airspeed, less rudder travel.
Lower airspeed, more rudder travel.
At what altitude does the half bank limit become visible?
31 500’
What does the wing maneuver load alleviation function do?
Reduces wing root bending and structural weight by deflecting the ailerons upward during positive load factor maneuvers.
What is the engine out compensation function?
Provides partial automatic yaw compensation in flight engine failure.
What are the three types of direct mode?
PFCC
REU
AFCU
What visual indications would you receive if the aircraft reverts to direct mode?
Amber FLT CTRL DIRECT message on the EICAS
DIRECT displays in amber in the upper left hand corner of PFD
When does the aircraft revert to REU direct mode?
When all PFCC’s have failed or all signals to the REU’s are lost.
What do you lose functionality wise between PFCC direct and REU direct?
Sidestick priority
Ground spoilers
Multifunction spoilers must be deployed manually
Pitch trim rate is slower
When does the the FBW system revert to AFCU direct mode?
When control requirement is lost due to multiple REU failures.
What visual messages display in case of reversion to AFCU direct mode?
Red DIRECT message in upper left corner of PFD.
FLT CTRL DIRECT warning message on EICAS
What control functions are available during AFCU Direct mode?
Manual HSTAB Trim
Rudder trim
Manual aileron trim
What hydraulic systems power the ailerons?
The #2 and #3 hydraulic systems power a PCU each per aileron.
If FBW is operating in AFCU direct mode, how are ailerons powered?
Via AFCU using hydraulic system #3
