General systems Flashcards
What does SG 2 provide?
Provides info to PFD2 and MFD2
What does SG 1 provide?
Provides info to PFD1, MFD 1, and EICAS
IC 600 computers under cockpit floor
When is the stick pusher inhibited?
- On the ground
- Below .5 G
- If the quick disconnect button is pressed
- If either SPS cutout button has been pressed
- Above 200 KIAS
- If either SPS channel is inoperative
- Below 200’ (or, if RA is inoperative, less than 10 seconds after takeoff)
What is a pack overheat?
Air leaving the pack is too hot
What is a pack overload?
- Excessive pressure entering pack.
2. Excessive temperature downstream of compressor.
When will pack(s) automatically shut down?
- One engine inoperative below 9,700’ (unless APU is used)
- Go-around or non-ALT TO takeoff
a. Less than 1,700’ AGL RA
b. Engine bleeds on, and
c. TO1 - Pack 1 off with anti-ice below 24,600’ (if pack 2 is on)
- Pack overload
- Pack overheat
- Engine start
- Essential power
- Loss of bleed source
What is provided by the cross-channel data link?
Same-side FADECs 1. Fault protection Active FADEC fails, standby takes over 2. Engine start FADECs take turns starting engines 3. Ignition Each FADEC controls its own ignition
What is provided by the inter-nacelle data bus?
Links cross-side active FADECs
- Thrust reverse arming
Both thrusts must be at idle - ATTCS
Automatic Takeoff Thrust Control System
What is in the aft avionics bay?
PRESSURIZED
- FADECs
- DFDR
- CVR
- HSCU
What functions are provided by the hydraulic system manifold?
- Fluid filtering (Pressure and return lines)
- Overpressure relief (Main and electrical pumps)
- Pressure indications (Main and electrical pumps)
What happens upon detection of smoke or fire inside the baggage compartment?
Smoke detector sends a signal to:
- Deactivate the baggage compartment fan
- Illuminate baggage fire extinguisher button
- Generate BAGG SMOKE EICAS warning
What does pressing the APU EXTG button do?
- Commands FADEC shut down of APU
- Closes fuel at APU AND APU Fuel 1 SOV
- Discharges the fire extinguisher bottle into the APU compartment
Describe the shutoff valve for the engine-driven pump
Location: Between reservoir and engine-driven pump
It will close through:
1. Engine fire extinguishing handle
2. Dedicated button on overhead panel
(Engine pump shutoff value– Guarded)
Hot Bus 2
- Courtesy/ Stair Lights 1
- Engine 1 Fire Extinguishing
- Engine 2 Fire Extinguishing
- Fuel Shutoff Valve 2
- Hydraulic Shutoff Valve 2
Either on ground or in flight, abort engine start immediately when:
- No lightoff (ITT does not rise) within 10 seconds after first fuel flow indications (on ground only)
- ITT approaches start limit
- N2 decreases or remains steady for more than 30 seconds
(hung start) - N2 indicates no rotation up to 10 seconds after the start
command - Any unusual noise or vibration occurs
- Engine instruments indicate abnormal conditions
- Flames are visible from the exhaust pipe
- Oil pressure does not reach at least 34 psi after the engine
reaches stabilized idle
What is installed in the forward avionics compartment?
- ADC
- Transponder mode S
- Integrated communication unit C Aural warning computer
- FMS
- AHRS
- Passenger address
- Integrated navigation unit
- Inverter
- Dimmers
- Backup battery
What is included in the Integrated Navigation Unit?
- VOR
- Localizer
- Glideslope
- Marker Beacon
- ADF
- DME (6-channel)
- Audio digitizers
What happens when you place the gear lever down?
It signals the LGEU to command:
1. Landing gear electrovalve 2. Nose gear doors solenoid valve
Hydraulic system 1 supplies pressure to:
1. Landing gear doors 2. Actuators 3. Uplock devices
How many uplock/downlock sensors are there?
What is the power source?
Essential power
Each gear has 2 uplock sensors and 2 downlock sensors
3rd uplock sensor may be installed for nose gear doors
What is the power source for the air/ground sensors?
Each main gear:
1 Essential
1 DC
Nose gear
1 DC
What malfunctions could cause the Landing Gear air/ground fail message?
- 2 or more air/ground sensors fail
- There is a lack of signal majority among sensors
- The LGEU fails
What comprises the braking system?
- Normal braking system
- Emergency/ parking brake system
- Gear- retracting in-flight braking system
What is the normal brake system control/command/supply?
- Control– pedals
- Command
Electronically commanded and monitored by ESSENTIALLY POWERED Brake Control Unit (BCU) - Supplied by Hydraulic Systems 1 and 2
What controls the emergency/ parking brake system?
Parking brake handle
What controls gear-retracting in-flight braking?
- Both hydraulic systems
2. Mechanical stop in nose gear wheel well
What are BCV’s?
What do they control?
Brake Control Valves
The BCU receives signals from pedal position transducers and commands 4 BCV’s to modulate required pressure to wheel brakes
Outboard wheels– BCV 1 and 4
Inboard wheels– BCV 2 and 3
What protection is provided with normal braking?
- Touchdown protection
- Anti-skid protection
- Locked wheel protection
What does touchdown protection provide?
Brake actuation is allowed:
1. After 3 seconds from the last touchdown, OR 2. After the wheels have spun up to 50 knots
If it is a bounced landing, countdown resets after each runway contact.
When does the SPS test button illuminate?
- Initial power-up
- If SPS has not been tested
- If SPS has failed
When do the rudder systems automatically shut off?
All conditions are met simultaneously:
- Rudder deflected above 5 degrees +/- 1 degree
- Force above 130 lb on the pedal to counteract rudder deflection
- Both engines running above 56% N2
What drives each rudder?
- Forward rudder is driven by the control system
2. Aft rudder is linked to forward rudder and deflected as a result of forward rudder deflection.
What commands and actuates the rudders?
Power Control Unit (PCU) is Commanded through
1. Cables from the pedals to the rear fuselage, or 2. Autopilot
However, it may revert to mechanical mode.
No artificial feel or trim available
If there is a loss of electric power, how long will the attitude indicator remain erect?
- Original 40 minutes (Essential power), then
2. 9 additional minutes
Describe the FDRS location and recording?
Location: Rear avionics compartment
Records past 25 hours of information
Begins:
1. Beacon is turned on 2. Airborne
Ends:
1. 5G Impact 2. Submersion in water
What is on Hot Bus 1?
- ELT Control Panel
- Engine 1 Fire Extinguisher
- Engine 2 Fire Extinguisher
- Pressure Refueling 3
- Fuel Shutoff Valve 1
- Hydraulic Shutoff Valve 1
- APU Control
What is the takeoff inhibition logic for messages?
Begins at V1-15 knots Deactivated when: 1. RA>400' 2. Calibrated airspeed less than 60 knots 3. 1 minut
What is the landing inhibition logic for messages?
Activates below 200 feet RA
Deactivated when:
1. Airplane is on the ground 3 seconds or more, OR 2. After 1 minute
What is the power source for RMUs?
RMU1 Power/Control: Essential DC Bus 1
RMU2 Power/Control: Essential DC Bus 2
How are landing gear, steering, and braking commanded and actuated?
Gear extension/retraction, steering, and braking functions are:
- Electronically controlled
- Hydraulically assisted
- Electronically monitored
Describe the air/ground sensor operation.
Detects landing gear shock absorber compression and relays the information to the LGEU
Describe air/ground sensor locations
5 total weight on wheels proximity switches
2 on each main landing gear
1 on the nose landing gear leg
What is the logic used by the LGEU for air/ground signals?
If all proximity switch signals are valid:
4 signals processed to assure that at least 3 indicate identical status
If 1 proximity switch signal is invalid:
3 signals processed to assure that at least 2 indicate identical status
If 2 proximity switch signals are invalid:
The two remaining signals are processed only if both send the same signal; otherwise, channels are de-energized.
Where is the nose landing gear proximity switch signal sent?
- Thrust reverser logic
2. Steering control
How can you turn on the RMUs?
There is NO master switch for the RMUs; when the airplane is energized, both RMUs (and the EICAS) are automatically turned ON
However, only COM 1 radio is available until AVIONICS MASTER is switched ON (Dashes will show on the remaining RMU fields)
What do you do for a jammed aileron?
What is the result?
Pull the red disconnect handle
This separates the free aileron from its jammed counterpart at the torque tube assembly
CA- Left Aileron
FO- Right Aileron
What do you do for a jammed elevator? What is the result?
Pull the red, vertical disconnect handle
This separates the elevator controls at the torque tube
Controls will operate independently
1. CA has left elevator
2. FO has right elevator
How is pitch trim powered?
A dual-channel system is installed
Main channel: DC
Operated via either control column trim switch
Backup channel: Essential
Operated via trim switch on control pedestal
What prevents excessive pitch trim actuation?
- Automatic cutout at 3 seconds
- Quick disconnect button
Cutout trim commands from HSCU
Will then select pitch trim cutouts on control pedestal
What is the procedure if there is no pitch trim indication on the EICAS?
Position the horizontal stabilizer to the takeoff setting by using the markings on the vertical stabilizer
Ailerons:
If all hydraulic assistance is lost…
The mechanical linkage is fully capable of positioning the ailerons, although control forces will vary according to aircraft speed
Describe Aileron Shutoff Sys 1 and Sys 2
Both hydraulic systems supply pressure to each aileron PCA
Buttons allow pilots to cut off hydraulic assistance by closing the DC power shutoff valves
Use if hydraulic malfunction is suspected
If normal DC power is lost, aileron shutoff valves will…
fail OPEN
How are ailerons controlled?
- Control yoke actuation
- Mechanical linkage
- Power Control Actuator (PCA)
Provides hydraulic assistance from both systems
What are the secondary flight controls?
What actuates each?
- Speed brakes : Hydraulically assisted
- Ground spoilers: Hydraulically assisted
- Flaps: Electrical
- Trim systems: Electrical
What are the primary flight controls?
What actuates each?
- Elevators: Purely mechanical
- Ailerons: Hydraulically actuated
- Rudder: Hydraulically actuated
Passenger Oxygen indicators
- Oxygen ON indicator light
Indicates that electric latches are energized - No smoking and Fasten Seat Belts signs illuminate in passenger cabin
Cabin altitude indication color
Normal mode operation
Green: -1500 to 8,300
Amber: 8,400 to 9,900
Red: 10,000 to 37,000
Differential pressure indications: Colors
Green: 0.0 to 7.9 psi Amber: -.3 to -.1 psi 8.0-8.3 psi Red: -.5 to -.4 psi 8.4 to 10 psi
What does the aural warning “CABIN” mean?
Alerts the crew that the cabin altitude is above 9,900’ +/- 100’
What happens if there is a negative differential pressure?
Outflow valves go to full open
Allows outside air to enter the outflow valves
What will the “DUMP” button do?
It will dump the cabin pressure to 14,500’
It will not work if CPCS (DC power) is not working
What 2 pilot actions are needed for automatic pressurization?
- Set landing elevation in the digital controller
- Manual control knob in full down position
This slaves pneumatic outflow valve to electropnuematic outflow valve
Describe the electro-pneumatic outflow valve
Suction is controlled by the Cabin Pressure Control System
CPCS is DC powered
Describe the CPAM
Cabin Pressure Acquisition Module
Essential power
Provides:
1. Cabin pressure 2. Cabin differential pressure 3. Cabin climb rate, up to 2000' or 4000' a minute
Acquires outside pressure from pitot-static 3
What is the power source for windshield heat?
Captain: DC
FO: Shed
When are most probes heated?
Anytime 1 engine is running, except:
- TAT sensors: OFF on the ground unless engine A/I is ON
- Ice detectors: Not heated unless ice is detected
- Pitot heat #3 also always heats in flight
- Pressurization static port will always heat in flight
What is 14th stage air used for?
- Anti Ice
- Cross-bleed engine start
- Low engine thrust
How does the High Stage Valve work?
Locks out 14th stage air until needed
Colocated with pressure sensor
If pressure drops enough, it opens
What is the heat exchange between?
Fan air (from engine--cold) and Bleed air
If air leaving the pre-cooler is hot…
Fan air valves will modulate more open
What are the 3 positions of the cross bleed valve switch?
- Closed: Closed
- AUTO: Normally closed; will open automatically for engine start
- OPEN: APU air is available for Pack 2
APU is on
#2 Engine started
If XBLEED is…
CLOSED, it is 2 separate systems
If you open XBLEED, APU Bleed Air Valve will close per system logic; engines have priority
Bleed Leak message
WARNING
Also, Bleed Button will display “LEAK” for engine leaks
Duct leakage in a bleed line
System logic will command the associated bleed valve to close
What will close in response to a massive bleed leak?
Occurs in aft avionics
- Affected Engine bleed valve
- Affected high stage valve
- Crossbleed valve
- APU bleed valve
What bleed valves are essentially powered?
Engine Bleed Valve 1 and 2
Crossbleed Valve
APU Bleed
What is the power source for packs, gasper, and recirculation fans?
Packs: DC
Gasper: DC
Recirculation fan: Shed Bus 2
Describe Air Cycle Machine functioning
- Turbine spins a compressor that spins a fan.
Cooling occurs here - Air flows into a scoop and through the primary/secondary heat exchanger
- Dual temperature control valves allow some air to bypass the ACM and some to enter, thus it sets the end temperature
What does the recirculation fan do?
Collects air from the cabin and sends it back to the pack
What do the gaspers supply?
- Passenger outlets
- Rear avionics bay (cannot be shut off on the ground)
- Oxygen cylinder
Describe the forward avionics bay recirculation fans and exhaust
DC
Fans are always on when aircraft is powered
If temperature > 75 degreesF, NACA inlets open and exhaust fans turn on.
They operate until <66 degrees F
Describe the Ram Air Valves
Emergency ram air lines allow ram air to go to cockpit and cabin
Should only be in emergency position if in flight with both packs off
Always in normal position on ground, ie, ram air is not flowing to the cabin
What does BATT 1 (2) OVTEMP mean?
WARNING
Associated battery temperature is above 70 degrees C
What does ELEC ESS XFER FAIL mean?
WARNING
Automatic transfer to the electrical emergency EDL configuration has failed
What does APU GEN OVLD mean?
CAUTION
APU generator current is above 400 Amps