Week 2 Day 1 Flashcards
When will the BFCU take charge of the fly by wire system?
If you have a failure of all 4 FCC channels
How many REU’s are there? What is unique about them?
- 16 REU’s. One for each flying control surface
- All same part number and software revision status
How many MCE’s are there?
7 MCE’s. One for each EBHA install
How many EHSA assemblies are there? What does EHSA stand for, and what is an assembly comprised of?
- 9 total
- Electro hydraulic servo actuator
- REU, EHSA manifold and actuator
How many EBHA assemblies are there? What does EBHA stand for, and what is an assembly comprised of?
- 9 EBHA assemblies
- Electrical backup hydraulic actuator
- REU, MCE, EB, HA manifold and actuator
In what order do you turn on the UPS and EBHA batteries and why?
EBHA prior to UPS so that MCE’s pass SPOST
How long does the SPOST take?
Approx 45 seconds
What aircraft mode is needed for EB (electrical backup) operation to occur?
Aircraft must be in air mode
Why would a flying control surface be in EBHA operation? (3 reasons)
- total aircraft hydraulic failure
- loss of all hydraulics at an individual service
- loss of all REU functionality at an individual surface
Where does the BFCU not receive inputs from? These will result in no speed brake or ground spoiler in BFCU mode. Aircraft will still have spoiler roll assist
- Speed brake handle
- aground spoiler system
For normal FCC operation, what parameters are required? (3 things)
- at least 2 smart probes operating, providing data and heated
- at least 1 IRU operating and providing data
- must have an operational HSC system (HSCU) and communicating with the FCC’s
When is FCC alternate mode in operation?
- Normal mode parameters not met
- can revert back to normal through FCC reset switch (if parameters now met). Also can happen automatically
When is FCC direct mode in operation?
- FCC channels in disagreement
- cannot FCC reset without downing power
What is the other function of the FCC reset switch?
Prior to electrical rigging, it tells all REU’s to be ready for rig
In the alternate and direct FCC modes, what are the two control laws?
- high speed gain (340 knots)
- low speed gain (250 knots)
What type of inputs are there into the FCS system?
Conventional (stick and pedals) input by pilot, copilot or autopilot
How is the FCS system controlled and actuated?
Electrically controlled and hydraulically actuated
Hi is the FCC system displayed?
- 2/3 synoptic - detailed or standard
How many cables are there in the flight control system? What are they for, and are they interchangeable?
- 4 total not interchangeable
- all for aileron control
- from control wheels to control modules (under cockpit floor)
What type of bus are the FCS command data buses?
Arinc 429
During normal FCC operation, what status are the EHSA and EBHA assemblies in?
Both active
What distinguishes B modules from A modules in the FCC’s?
B have additional lobes
In the FCC, each channel has two channels, which are they?
Control and monitor
What powers the FCC? (Two power sources)
- UPS battery
- Essential DC bus
What could a blue FCS maintenance required CAS message indicate?
FCC channel module software not identical
What position are the monitor modules placed in the FCC?
Monitor are nearest the fan (inboard)
On even calendar days, which FCC channels are in command of the fly by wire systems?
1A and 2B (UPS powered systems)
On odd calendar days, which FCC channels are in command of the fly by wire systems?
1B and 2A (ESS powered systems)
To dispatch with a failed FCC channel, where must the modules be placed?
In a UPS powered position (fly for 3 days)
When you pull a module from an FCC, what do you need to perform an inspection of module and back plane?
Torch and 6x magnifying glass
When changing an FCC module (or both modules in one channel), what follow ons are required?
SPOST only
When changing modules in both channels of an FCC, how do you do it?
Change one at a time, do the SPOST
When changing FCC modules from three channels, how do you do it?
Change one at a time, then SPOST, then electric rig
Where does the flight data recorder get flight data from?
- MAU’s
- not directly from the FCC’s
How do we know SPOST has finished?
Stick shaker (8 shakes)
Is there a stick pusher on the aircraft?
No, FCC’s won’t allow aircraft to stall in normal mode
In the RVDT clusters, why do we have 5 individual RVDT’s?
- 1 for each FCC channel 4
- 1 backup
What does the BFCU communicate with? And how?
- EBHA assemblies only
- commands only
BFCU reports to which channel modules of the FCC?
B channels
Can you repair a fly by wire harness?
No, replacement only
What are the four FCC normal mode sub modes?
- ground
- takeoff/landing
- cruise
- angle of attack
What do you lose in FCC alternate mode?
- Stall protection
- Autopilot
What do you lose in FCC direct mode?
- speed brake
- spoilers
- autopilot
- stall protection
When is low speed gain CLAWS in effect?
When flaps and landing gear handles are down
When is high speed gain CLAWS in effect?
When flaps and landing gear handles are up
When is FCC maintenance mode available? (Used for rigging and maintenance)
- On ground
- left and right wheel speed low
- flight control maint switch on
Ok aircraft 6165 and subsequent, or aircraft with ASC 37, what do ailerons also work as on touchdown?
Ground spoilers
Where is the BFCU located?
Underfloor behind the TRU’s
To disengage the BFCU, what has to happen?
- power cycle
- at least one FCC channel available
Which side are the pitch and roll RVDT clusters located?
- pitch left
- roll right
What is in the input shaft of the RVDT clusters, and in each RVDT, to insure against the negative effects of a mechanical jam in the cluster?
Shear point
What ensures correct RVDT installation on to the control module?
Splined shaft and alignment pin
On the EHSA actuator, how many position LVDT’s are there?
One
On the EBHA actuator, how many position LVDT’s are there?
Two
What prevents the EB manifold actuator, and the HA manifold actuator from fighting each other if minute differences occur?
Force equalisation loop
EBHA manifolds and MCE’s are located where on primary flight controls? (Inboard or outboard)
Inboard
EBHA manifolds and MCE’s are located where on spoilers? (Inboard or outboard)
Outboard
What prevents total loss of pressure in the EB and HA manifolds in event of hydraulic failure?
Check valves
When total hydraulic system failure happens, and the check valves in the manifolds operate, what happens to circulate fluid in the EBHA closed system?
MCE energises in built resolver and pump to move fluid. MCE ports fluid as per normal
If you lose an REU, what happens to the associated actuator?
Goes into damping mode
What if you lose both REU’s on a single flight control surface?
MCE takes over, flight control goes into EB mode. HA actuators go into dampen mode
How far do you have to pull and REU or MCE from the manifold before rotating?
1/4 inch
What part of the EBHA/EHSA manifold provides gust lock protection?
Compensator
How do you depressurise the EBHA/EHSA manifolds for maintenance?
Relief valve plunger and pin
When are suite A checks performed?
- every 600 hours
- whenever fly by wire components are changed
During the suite A check, how often are each of the components checked?
Twice
Where do right system hydraulic lines run?
Along front of the wing then through to the rear spar
Where do left wing hydraulic lines run?
Along the trailing edge
When removing a flight control actuator, where do you remove the toggle link?
From the control surface, not the actuator
What is the only flight control surface with a stand alone RVDT and why is it there?
- Elevator
- redundancy for pitch control
How many control module assemblies are there?
- 3
- 1 rudder (pilot and copilot)
- 2 pitch and roll
If you had to replace an RVDT cluster, how would you check the binding?
Low resistance ohmeter
How do you relieve manifold pressure in outboard spoiler EHSA manifolds?
Compensator pins and power retract spanner
How do you relieve manifold pressure in an aileron EHSA manifold?
Compensator pin
How do you relieve manifold pressures in mid and inboard spoiler EHSA manifolds?
Power retract spanner
