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FCOM NG System Description > 7. Engines, APU > Flashcards

7. Engines, APU Flashcards

1
Q

A/T LIM Indication

A
  • The FMC is not providing the A/T system with N1 Limit values,
  • A/T is using a degraded N1 thrust limit from the related EEC
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2
Q

EGT Start Limit Redlines

A
  • Shown for ground starts and some in-flight starts as determined by EEC,
  • Displayed until the engine achieves Stabilized IDLE (approximately 59% N2)
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3
Q

EEC Abnormal Start Protections

A
  • For ground starts only it has 4 Protections:
    1-) Hot Start (rapid rise in EGT or approaching start limit),
    2-) Compressor Stall,
    3-) EGT Start Limit Exceedences,
    4-) Wet Starts (15s)
  • For all EEC turns off ingnition and shuts off fuel to the engine,
  • For Hot start and Compressor Stall, EGT white box flashes white,
  • If EGT limit exceeded both box and dial turns initially. Turns to white when below limit,
  • After engine shutdown it turns to red again
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4
Q

ENG FAIL Alert

A

Displayed:
- In amber and on the EGT indicator,
- Engine operating below sustainable IDLE (< 50% N2) and,
- Engine Start Lever in IDLE position

Alert remains until:
- Engine recovers or,
- Engine Start Lever moved to CUTOFF or,
- Engine Fire Switch pulled

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5
Q

Upper DU Engine Alerts

A
  • Illuminates amber,
  • All boxes blink for 10s,
  • After 10s related alert remains on steady
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6
Q

Engine Alerts Blinking Inhibit

A
  • During T/O from 80KT to 400FT or 30s after reaching 80KT, whichever occurs first,
  • During landing below 200FT until 30s after touchdown,
  • When blinking inhibited, alerts illuminate steady
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7
Q

Secondary Engine Indications Automatic Pop-up

A
  • Inflight when an Engine Start Lever moved to CUTOFF,
  • Inflight when an engine fails,
  • When a secondary engine parameter exceeds normal operating range,
  • Once displayed they cannot be cleared until the condition is no longer present
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8
Q

Low OIL PRESS Amber Band

A
  • Not displayed below 65% N2,
  • Variable depending on N2 above 65%
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9
Q

OIL QTY Windmilling Value

A

As low as zero is normal if windmilling N2 RPM < 8%

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10
Q

X-BLD

A
  • Location is above N2 dial,
  • Displayed when airspeed is less than required for windmilling start
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11
Q

ENGINE START Switch GRD

A
  • Opens Start Valve (using Battery power),
  • Closes Engine Bleed Valve (using Battery power),
  • For ground starts, arms selected igniter to provide ignition when Engine Start Lever is moved to IDLE,
  • For inflight starts, arms both igniters to provide ignition when Engine Start Lever is moved to IDLE,
  • Releases to OFF at Start Valve Cutout
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12
Q

ENGINE START Switch OFF

A

Ignition is normally OFF but both igniters activated when Engine Start Lever is in IDLE and:
- An uncommanded rapid decrease in N2 occurs or,
- N2 is between 57% and 50% or,
- Inflight, N2 is between idle and 5%

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13
Q

ENGINE START Switch CONT and FLT

A

CONT:
- Provides ignition to selected igniters when engine is operating and Engine Start Lever is in IDLE,
- Inflight, provides ignition to both igniters when N2 is below idle and Engine Start Lever is in IDLE

FLT:
- Provides ignition to both igniters when Engine Start Lever is in IDLE

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14
Q

REVERSER Light

A

Illuminates when:
- Isolation Valve or Thrust Reverser Control Valve is not in commanded position,
- One or more Thrust Reverser sleeves are not in commanded state,
- Auto-restow circuit has been activated,
- A failure has been detected in Synchronizaiton Shaft Lock circuitry

During normal operation:
- Thrust Reverser commanded to stow and extinguishes 10s later when Isolation Valve closes,
- If illuminated more than 12s, MASTER CAUTION and ENG illuminates,

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15
Q

ENGINE CONTROL Lights

A

Illuminates for a Non-dispatchable fault and operates when:
- Engine is operating and,
- Airplane on ground and,
- Below 80KT prior to T/O or,
- Approximately 30s after touchdown

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16
Q

EEC Switches

A

ON:
- If only ON shown, indicates normal control mode is selected,
- When ON is not in view, the EEC has been MANUALLY selected to the Hard Alternate mode

ALTN:
- EEC has AUTOMATICALLY or MANUALLY switched to alternate control mode,
- If both ON and ALTN in view, EEC has automatically switched to alternate mode,
- EEC provides rated thrust or higher

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17
Q

Reverse Thrust Lever Lock

A

Blocked at Reverse Idle position until related Thrust Reverser is > 60% deployed

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18
Q

Engine Start Levers IDLE

A
  • Energizes Ignition system through EEC,
  • Electrically opens Spar Fuel Shutoff Valve in the wing leading edge outboard of the pylon,
  • Electrically opens Engine-Mounted Fuel Shutoff Valve via the EEC
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19
Q

APU OVERSPEED Light

A

Illuminated when:
- APU RPM limit has been exceeded resulting in an automatic shutdown,
- Overspeed Shutdown Protection feature has failed a self-test during a normal APU shutdown,
- If illuminated when APU switch is placed to OFF, light extinguishes after 5 minutes,
- Light is disarmed when APU switch is OFF

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20
Q

APU FAULT Light

A

Illuminated when:
- A malfunction exists causing APU to initiate an automatic shutdown,
- If illuminated when APU switch is placed to OFF, light extinguishes after 5 minutes,
- Light is disarmed when APU switch is OFF

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21
Q

APU LOW OIL PRESSURE Light

A

Illuminated when:
- During start until APU oil pressure is normal,
- Oil pressure is low causing an automatic shutdown (after start cycle complete),
- If illuminated when APU switch is placed to OFF, light extinguishes after 5 minutes,
- Light is disarmed when APU switch is OFF

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22
Q

Engines General

A
  • CFM56-7 axial flow,
  • Dual rotor N1 and N2,
  • N1 consists of: Fan, LP Compressor and LP Turbine,
  • N2 consists of: HP Compressor and HP Turbine,
  • N2 rotor drives Engine Gearboxes,
  • Bleed air powered Starter Motor is connected to N2 rotor
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23
Q

EEC

A
  • Electronic Engine Control,
  • Dual channel EEC regulates each engine,
  • With each engine start or attempt, the EEC alternates between control channels,
  • Monitors A/T and Flight Crew inputs to automatically set engine thrust,
24
Q

EEC and Engine Indications

A
  • When EEC not powered N1, N2, Oil Quantity and Engine Vibration are displayed directly from engine sensors,
  • During Battery Start only N1, N2 and Oil Quantity is shown,
  • Positioning ENGINE START switch to GRD supplies power to the EEC and displays all engine parameters,
  • EEC is not powered until 15% N2
25
EEC Modes
Normal: - Uses sensed flight conditions and bleed air demand to calculate N1 thrust ratings, - EEC compares commanded N1 and actual N1 adn adjusts fuel flow to achieve the commanded N1 Soft Alternate: - If required signals are not available to operate in the normal mode, EEC automatically changes to Soft Alternate mode, - Loss of either DEU results in Soft Alternate Mode, - The ALTN and ON lights shown together, - EEC uses the last valid flight conditions to define engine parameters, - If ambient conditions change, thrust rating shortfalls or exceedances may occur Hard Alternate: - Soft Alternate changes to Hard Alternate by: retarding the thrust levers to IDLE (ON light remains) or, - Manually selecting ALTN with the EEC switch (ON light extinguishes), - Thrust is always equal or greater than normal mode for the same thrust lever position, - EEC limiting is not provided and Maximum Rated Thrust may be reached before the forward stop
26
Full Rated T/O and Maximum Rated Thrust
In normal mode: - Full Rated T/O Thrust is available before the forward stop, - The Maximum Rated Thrust is available at the forward stop
27
EEC Structural Limit Protection
- EEC provides N1 and N2 redline overspeed protection in both normal and alternate modes, - EEC does not provide EGT redline exceedance protection
28
Approach Idle Operation
General: - N1 and N2 RPM is higher than Flight Idle, - This improves engine acceleration time in the event of a go-around, Engages when: - EAI Switch ON for either engine or, - < 19000FT MSL and left or right Main Landing Gear is down and locked or, - < 19000FT MSL and left or right Flaps are 15 or greater or, - If there is a fault preventing EEC to receive Flaps or Gear Signals, engages < 19000FT, - Maintained until after touchdown when Ground Idle is selected
29
Engine Fuel System
- Fuel delivered under pressure from fuel pumps, - Flows through Spar Fuel Shutoff Valve at the engine mounting wing station, - Then passes through 1st stage Engine Fuel Pump where pressure increased, - Then passes through 2 fuel/oil Heat Exchangers (IDG and Main Engine Oil), - After that a Fuel Filter removes contaminants (bypasses it if it becomes saturated), - Then 2nd stage Engine Fuel Pump adds more pressure before fuel reaches HMU, - EEC meters fuel through HMU, After HMU fuel flows through Engine Fuel Shutoff Valve
30
Fuel Flow Measurement Location
After passing Engine Fuel Shutoff Valve
31
Engine Oil System
- System pressurized by the Engine Driven Oil Pump, - From the pump it goes to engine bearings and gearbox, - Sensors for oil temperature and pressure indicators and LOW OIL PRESSURE alert are downstream of pump prior the engine lubrication, - Oil is returned to the tank by Engine Driven Scavenge Pumps, - After the pump oil passes through Scavenge Filter (bypasses it if it becomes saturated), - 2 Pressure sensors before and after Scavenge Pump used to illuminate OIL FILTER BYPASS - Prior returning to the tank, the Oil passes through the Main Engine Oil Cooler
32
Fuel Flow and EGT During Engine Start
- Initial Fuel Flow indications lag actual Fuel Flow by approximately 2s, - During engine start an EGT rise may occur before Fuel Flow indication
33
Engine Ignition System Power Source
- Left Igniters supplied by the associated AC Transfer Busses, - Right Igniters supplied by the AC Standby Bus
34
Auto-Relight
- Provided for Flameout Protection, - Whenever EEC detects an Engine Flameout, both igniters are activated, - Flameout detected when: Uncommanded rapid decrease in N2 occurs or N2 is below idle RPM
35
Inflight Starting EGT Limit
- Can be shown depending on the start logic as determined by the EEC, - If only the EGT limit is shown, this is the inflight start EGT limit, - If both EGT Redline and EGT Start Limit are shown, EGT Start Limit is the start limit
36
Thrust Reverser Basic Operation
- Aft movement of the L & R translating sleeves causes Blocker Doors to deflect Fan Discharge Air forward, - Air deflected through Fixed Cascade Vanes, producing reverse thrust
37
Thrust Reverser Deployment
- Can be deployed when RA senses less than 10FT or Air/Ground Safety Sensor in the ground mode, - When selected: 1-) Electro-mechanical Lock releases, 2-) Isolation Valve opens, 3-) Thrust Reverser Control Valve moves to deploy position, allowing hydraulic pressure to unlock and deploy the Reverser System, 4-) An Interlock mechanism initially restricts movement of the Reverse Thrust Lever movement (Sleeves > 60% open), 5-) After Sleeves are deployed, Reverse Thrust Lever can be raised to Detent 2 or further to Maximum
38
REV Indication
Amber: - When either Reverser Sleeve moves from the stowed position, Green: - Thrust Reverser reaches deployed position
39
Thrust Reverser Stowing
- Downward motion of Reverse Thrust Lever past Detent No. 1 (Reverse Idle) initiates the stow command, - When Reverse Thrust Lever reaches full down position, Control Valve moves to the stow position, - Allowing hydraulic pressure to stow and lock the Reverser Sleeves, - After the Thrust Reverser stowed, the Isolation Valve closes, - Then Electro-mechanical Lock engages
40
Thrust Reverser Stowing Caution
- A pause in movement of the Reverse Thrust Lever past Detent No. 1 toward the stow position, - May cause MASTER CAUTION and ENG lights to illuminate, - A pause of approximately 16s engages Electro-mechanical Lock and prevents Sleeves from further movement, - Cycling the Thrust Reversers may clear the fault
41
Thrust Reverser Stowed Protections
- In stowed position an Electro-mechanical Lock and, - Hydraulically operated Locking Actuator inhibit motion to each Reverser Sleeve until extension is selected, - Also has an Auto-Restow circuit
42
Thrust Reverser Auto-Restow Circuit
- Compares actual and commanded position, - In the event of incomplete stowage or uncommanded movement circuit opens the Isolation Valve, - Commands the Control Valve to the stow position directing hydraulic pressure to stow the sleeves, - Once activated, the Isolation Valve remains open and Control Valve held in stowed position until, - Thrust Reverser is commanded to deploy or corrective maintenance action is taken
43
Airborne Vibration Monitoring System
- Primary function is the display of Low and High Pressure Rotor Synchronous vibration, - Also used to balance the Low Pressure Rotor, - Balancing reduces high vibration or audible noise and tactile vibration
44
APU
- Auxiliary Power Unit is a self-contained gas turbine engine installed within a fireproof compartment
45
APU Fuel Supply
- Comes from left side of the fuel manifold when AC Fuel Pumps are operating, - If AC Fuel Pumps not operating, fuel is suction fed from No. 1 tank, - During APU operation, fuel is automatically heated
46
APU Engine and Cooling Air
- Engine air enters via inlet door on the right side of the fuselage, - APU exhaust gases discharge via Exhaust Muffler on the tail, - APU cooling air enters via Cooling Air Inlet above the Exhaust Outlet, - Cooling air circulates through the APU compartment, oil cooler and vents via Exhaust Outlet
47
Electrical Requirement For APU Operation
- Battery Switch must be ON, - Power to start comes from AC Transfer Bus 1 or the Main Battery if AC power not available, - Moving Battery Switch to OFF automatically shuts down APU due to power loss to the Electronic Control Unit
48
APU Start
- Moving APU switch to START initiates opening of the Air Inlet Door, - When Inlet Door reaches fully open position, the start sequence begins, - After reaching proper speed, ignition and fuel are provided, - When APU is ready to accept a bleed air or electrical load the APU GEN OFF BUS light illuminates
49
APU Indications During Start
- EGT may fluctuate between 0-1100 degrees, - LOW OIL PRESSURE light may cycle on and off several times
50
APU Start With Battery Only
When the AC Meters Selector is set to APU GEN: - CPS FREQ indication will be blank, - AC VOLTS indication will be 0, - When APU GEN OFF BUS light illuminates actual values will be shown
51
Engine Start Cycle Duration
May take as long as 120s
52
Recommended Wait Time for APU Bleed Air
- After start, operate the APU for 2 full minutes before using it as a bleed air source, - Before shutdown, operate APU for 1 full minute with no bleed air, - When the APU switch moved to OFF, this time delay is met automatically
53
APU Shutdown
- Shutdown occurs automatically 60s after APU switch moved to OFF, - When the APU speed decreases sufficiently during shutdown, the Fuel Valve and Inlet Door close, - If the Fuel Valve does not close, the FAULT light illuminates after approximately 30s, - Immediate shutdown can be done by pulling APU Fire Switch
54
ECU
- Electronic Control Unit of the APU, - If detects a fault that may cause damage to the APU or the aircraft, - It will automatically execute a protective shutdown, - Automatically controls APU speed through the Electronic Fuel Control
55
APU Bleed and Electrical Load Shedding
If EGT raises above acceptable levels: - During engine start, electrical load shedding occurs first, - Other times, Inlet Guide Vanes move toward a closed position, reducing bleed air extraction first
56
APU Automatic Load Shedding
If the APU is the only source inflight: - All Galley and Main Busses are automatically shed, - If still not enough both IFE Busses are automatically shed On the ground: - APU attempts to carry a full electrical load, - If overload sensed, APU sheds Galley and Main Busses until the load is within limits Manual restoration of Galley and Main Bus power can be attempted via cycling CAB/UTIL switch

FCOM NG System Description (16 decks)

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