CFM56-5B Engine Systems Quiz: Test Your Knowledge

Posted on May 6, 2024 in Technology

CFM56-5B Engine Systems Quiz

Fuel System

Question 1

The fuel bypassed from the Hydro-Mechanical Unit (HMU) is used to:

  1. Actuates the Variable Stator Vanes (VSVs) and Variable Bleed Valves (VBVs)
  2. Provides Fuel Flow meter information
  3. Cool the Integrated Drive Generator (IDG) Oil (IDG Oil Cooler)

Question 2

What controls the Fuel Return Valve (FRV)?

  1. The HMU
  2. The Generator Control Unit (GCU) depending on IDG temperature
  3. The Electronic Control Unit (ECU)

Question 3

The Variable Bleed Valve (VBV) system provides:

  1. Proper operation of the Low-Pressure Compressor (LPC) in some speeds
  2. Proper operation of the Low-Pressure Turbine (LPT) in all speeds
  3. Proper operation of the LPC in all speeds

Question 19

The oil/fuel heat exchanger has:

  1. One bypass valve only for the fuel system
  2. One bypass valve only for the oil system
  3. Two bypass valves for oil and fuel respectively

Question 20

Fuel flow primary discharge in the combustion chamber is reached by:

  1. Burner Staging Valve (BSV)
  2. HMU
  3. Internal component inside of the fuel nozzle

Question 27

The bypass fuel from the HMU goes to:

  1. The fuel tank directly
  2. The IDG Oil Cooler
  3. The main pump directly

Question 29

The fuel bypassed from the HMU is used to:

  1. Provide Fuel Flow meter information
  2. Cool the IDG Oil (IDG Oil Cooler)
  3. Actuates the VSVs and VBV

Question 30

What happens if the FRV is commanded by the V1 solenoid?

  1. No Fuel Return Flow (NRFF)
  2. High Fuel Return Flow (HRFF)
  3. Low Fuel Return Flow (LRFF)

Question 31

What is the purpose of the V1 and V2 Solenoids inside of the FRV?

  1. They are designed to select No Fuel Return by the EIU
  2. To permit the GCU to control the IDG oil temperature (Low Flow Return, High Flow Return)
  3. They reconfigure internal valves under ECU control to select rates of flow return

Question 61

If the wash filter in the main pump is clogged, what happens with the burned fuel?

  1. Fuel burned is stopped and the engine shuts down
  2. Bypass inside the filter is activated
  3. Nothing, because the fuel burned is free flow

Question 64

Which are the operation modes of the Fuel Return Valve (FRV)?

  1. Zero flow, low flow, high flow
  2. Zero flow, secondary flow, high flow
  3. Primary flow, secondary flow, tertiary flow

Oil System

Question 4

The breather of the oil system is vented to ambient through:

  1. Accessory Gearbox (AGB) direct to the ambient
  2. Shaft and center body tube
  3. Transfer Gearbox (TGB) direct to the ambient

Question 16

The air/oil separator in the forward sump provides:

  1. A decrease of the oil temperature
  2. An increase of the oil consumption
  3. A decrease of the oil consumption

Question 28

What does “OIL FILTER CLOG” indication mean?

  1. Backup filter is clogged
  2. Any scavenge filter is clogged
  3. Main oil filter is clogged

Question 39

When the engine is running, the oil quantity decreases due to:

  1. Fuel leaks into the accessory gearbox
  2. Gulping effect of the engine
  3. Oil leaks controlled by FADEC

Question 75

The anti-siphon device prevents:

  1. Oil from the system gallery draining by gravity to the tank
  2. Oil from the aft sump draining by pressure to the oil pump
  3. Oil from the tank draining by gravity to the oil pump

Question 77

The breather of the oil system is vented to ambient through:

  1. AGB direct to the ambient
  2. Shaft and center body tube
  3. TGB direct to the ambient

Engine Control and Indication Systems

Question 6

In Full Authority Digital Engine Control (FADEC), when the ECU sends an order, the electrical signal goes to:

  1. The Engine Interface Unit (EIU) then to the component
  2. The HMU
  3. The component that is necessary to move/actuate

Question 7

The purpose of the thermocouple T5 (sensor) is:

  1. To be used just for trend monitoring, optional sensor
  2. To control the operation of the High-Pressure Turbine Case Cooling (HPTCC) system
  3. To show on the Electronic Centralized Aircraft Monitor (ECAM) the Exhaust Gas Temperature (EGT) of the engine

Question 8

The manual start push button controls:

  1. The Start valve
  2. The igniters in manual
  3. The Starter

Question 9

The engine oil system clog switch sends a signal to:

  1. ECU
  2. EIU
  3. Engine Vibration Monitoring Unit (EVMU)

Question 12

The N1 speed sensor sends a signal to:

  1. ECU and EIU
  2. ECU and FADEC
  3. ECU and EVMU

Question 14

The temperature sensor in the lubrication units is for:

  1. ECU calculations
  2. Indication on ECAM
  3. Condition monitoring

Question 15

What station identifies the temperature obtained at the exit of the LPT?

  1. T 4.9
  2. T3
  3. T5

Question 21

What happens in case of missing or invalid ID plug information to the ECU?

  1. The ECU is degraded on both channels
  2. The ECU uses the Flight Management Guidance and Envelope Computer (FMGEC) information
  3. The ECU uses the value stored for the previous plug configuration

Question 22

The start valve is:

  1. Electrically actuated by the ECU
  2. Pneumatically controlled by the EIU
  3. Pneumatically operated

Question 23

The frozen Fuel Flow value at Engine Shut down is reset:

  1. At the new Start (master switch ON)
  2. When the post-flight report is printed
  3. At airplane power down

Question 25

The EIU data bus is not available:

  1. The ECU uses an alternate start ignition
  2. When the ECU cannot start the engine
  3. The EIU goes to trial mode

Question 26

During MAN START, the start valve is opened:

  1. When the master control switch goes to ON
  2. Automatically at 50% of N2 speed
  3. When the manual push button is pressed

Question 33

The N1 rating limit is computed by:

  1. Flight Warning Computer (FWC)
  2. FADEC
  3. EIU

Question 35

An “AB” indication as start parameters on the System Display (SD) means:

  1. Both ignition systems are inoperative
  2. Auto start condition
  3. Manual start condition

Question 37

The big connector of the N1 speed sensor is to:

  1. Take speed information to the EIU
  2. Send speed information to ECAM
  3. Take angular phase of the N1 shaft to the EVMU

Question 38

The Fuel Return Valve is electrically controlled by:

  1. EIU
  2. EVMU
  3. ECU

Question 40

What is the LPTACC system fail-safe position?

  1. Closed
  2. It does not have a fail-safe
  3. Open

Question 44

N1 Exceedance will disappear after:

  1. A new start on the ground or ECU self-test
  2. Engine re-light
  3. A new start on the ground or maintenance action via the Multifunction Control and Display Unit (MCDU)

Question 46

The normal FADEC power comes from:

  1. Aircraft A/C bus
  2. Control alternator
  3. IDG

Question 48

The “CHECK” amber message is displayed when:

  1. There is a discrepancy between values on the ECU and Zone Controller
  2. There is a discrepancy between values on the ECU and DMC
  3. There is a discrepancy between values on the ECU and EIU

Question 52

The oil quantity transmitter sends a signal to:

  1. FWC and SDAC
  2. EIU and SDAC
  3. ECU and FWC

Question 57

What controls the Fuel Return Valve?

  1. The ECU
  2. The GCU depending on IDG temperature
  3. The HMU

Question 60

During normal operations, the ECU power comes from:

  1. Control alternator
  2. Directly from the IDG to ensure proper operation during flight
  3. Aircraft A/C bus

Question 70

The low oil pressure switch (LOP) sends a signal to:

  1. EIU and FWC
  2. FWC and SDAC
  3. ECU and FWC

Question 78

The oil pressure transmitter sends a signal to:

  1. ECU and SDAC
  2. EIU and ECU
  3. EIU and SDAC

Question 81

In the FADEC architecture, what signals go directly from the ECU to the DMCs ECAM?

  1. N1 – N2 – Oil Pressure (OIP) – Fuel Flow (F/F)
  2. N1 – N2 – T5 – EGT
  3. N1 – N2 – EGT – F/F

Question 82

The amber crosses in the F/F will indicate information:

  1. Degraded
  2. Exceeded
  3. Lost

Question 88

The Burner Staging Valve (BSV) is controlled by:

  1. EIU
  2. FADEC
  3. EVMU

Question 89

In normal operation, what reference does the ECU use to control the FRV?

  1. The IDG temperature
  2. The engine oil temperature
  3. The two FRV solenoids

Question 90

A red cross adjacent to the N2 digital information will indicate:

  1. Ideal value to put the Master Control switch ON
  2. Value was exceeded
  3. A reference thrust

Question 91

The master power indication used is:

  1. N1 Speed
  2. Engine Pressure Ratio (EPR)
  3. N2 Speed

Question 92

The engine oil temperature is used as a reference by:

  1. EIU
  2. ECU
  3. FWC

Engine Components and Airflow

Question 3

The Variable Bleed Valve (VBV) system provides:

  1. Proper operation of the Low-Pressure Compressor (LPC) in some speeds
  2. Proper operation of the Low-Pressure Turbine (LPT) in all speeds
  3. Proper operation of the LPC in all speeds

Question 5

The engine Anti-Ice system warms the nose cowl lip with:

  1. 9th stage source
  2. 4th stage source
  3. 5th stage source

Question 11

Where are the balancing screws installed?

  1. On the fan disk
  2. On the spinner front cone
  3. On the spinner rear cone

Question 17

The HPT rotor disk is cooled by:

  1. Compressor Discharge Pressure (CDP) through internal passages
  2. LPT Clearance Control System
  3. HPT Clearance Control system

Question 32

The engine Anti-Ice system uses compressor 5th stage air to warm the nose cowl lip. What stage provides the motive (muscle) pressure to the valve?

  1. 5th stage source
  2. 9th stage source
  3. 4th stage source

Question 34

The forward bearing for the N2 shaft is:

  1. 3B-3R
  2. 5R
  3. 1B

Question 36

The efficiency of the HP compressor is reached by:

  1. HPTACC
  2. LPTACC
  3. VSV

Question 41

The LPTACC system uses:

  1. LPC bleed air
  2. HPC bleed air
  3. Fan air

Question 47

The diffuser between the HPC and the Combustion chamber:

  1. Converts pressure (Ps) energy into velocity energy
  2. Converts axial flow into radial flow
  3. Converts velocity energy into pressure (Ps) energy

Question 49

The lubrication unit provides:

  1. Oil under pressure for lubrication, scavenge after lubrication, and return to the oil tank
  2. Oil under pressure only
  3. Scavenge before lubrication and oil under pressure after the scavenge

Question 50

What provides passage for the Vibration Sensor, N1 sensor, TGB, and Oil drain line?

  1. Fan Case Struts
  2. Outer Guide Vanes (OGBs)
  3. Fan Frame

Question 53

The forward bearing for the N2 shaft is:

  1. 3B-3R
  2. 5R
  3. 1B

Question 56

The HPT rotor disk is cooled by:

  1. CDP
  2. LPTCC
  3. HPTCC

Question 58

What airflow station identifies the HP compressor discharge position?

  1. Station 4.9
  2. Station 3
  3. Station 5

Question 65

The purpose of the VSV system is:

  1. To optimize LPC efficiency and improve stall margin
  2. To optimize HPT efficiency
  3. To optimize HPC efficiency and improve stall margin

Question 66

The EGT (T49,5) thermocouples are installed:

  1. At the LPT stage 2 nozzle assembly
  2. At the LPT exit
  3. Between the LPT and HPT

Question 68

What system limits the N2 to a maximum of 106%?

  1. The Fuel nozzles reducing the fuel to the combustion chamber
  2. The governor inside of the HMU
  3. The ECU by moving the VSV

Question 69

The Fuel Nozzles contain both primary and secondary fuel flow passages. How are they activated?

  1. They are activated because pressure rises in the flow divider valve
  2. They are activated by ECU control
  3. They are activated at the same time during engine start

Question 79

The efficiency of the compressor is reached by:

  1. LPTACC
  2. HPTACC
  3. VSV

Question 80

The VSV system is actuated by:

  1. Two actuators and two bellcranks
  2. One actuator
  3. One actuator and two bellcranks

Question 83

How are the fan blades designed?

  1. Inconel alloy; shroudless
  2. Titanium alloy; shroudless
  3. Titanium alloy; mid-span shrouded

Question 84

The forward sump in the Fan frame is the location of:

  1. Bearing Nr 4 to Nr 5
  2. Bearing Nr 1, Nr 2, and Nr 3
  3. Bearings Nr 1 and Nr 2 only

Question 86

What provides proper operation of the low-pressure compressor in all speeds?

  1. The HPT Nozzle Guide Vane
  2. The VSVs and Inlet Guide Vane (IGV)
  3. VBVs (12)

Starting and Ignition Systems

Question 8

The manual start push button controls:

  1. The Start valve
  2. The igniters in manual
  3. The Starter

Question 18

Among others, after which action does the FADEC power supply remain supplied for five minutes?

  1. Engine shutdown
  2. AUTO start procedure performed
  3. FADEC ground power push button pressed

Question 22

The start valve is:

  1. Electrically actuated by the ECU
  2. Pneumatically controlled by the EIU
  3. Pneumatically operated

Question 25

The EIU data bus is not available:

  1. The ECU uses an alternate start ignition
  2. When the ECU cannot start the engine
  3. The EIU goes to trial mode

Question 26

During MAN START, the start valve is opened:

  1. When the master control switch goes to ON
  2. Automatically at 50% of N2 speed
  3. When the manual push button is pressed

Question 35

An “AB” indication as start parameters on the System Display (SD) means:

  1. Both ignition systems are inoperative
  2. Auto start condition
  3. Manual start condition

Question 42

Which ENG. mode selector position must be set in order to perform a wet motoring?

  1. Normal
  2. CRANK
  3. IGN/START

Question 43

Which condition will activate manually the continuous ignition?

  1. Master control switch to ON during auto start
  2. Flame out detected by the ECU
  3. ENG. Mode selector to ING/START after the engine is running

Question 51

Which position of the ENG. Mode selector cannot activate the ignition system?

  1. ON
  2. CRANK
  3. IGN/START

Question 54

After ATO/MAN start, the IGN selection is back to the NORM position:

  1. Automatically
  2. Or it must remain on the IGN/START position
  3. Manually

Question 87

In the Engine mode selector, the CRANK position allows:

  1. Dry & Wet motoring without ignition
  2. Motoring and Ignition
  3. Crank ignition and no fuel

Thrust Reverser System

Question 10

The reverse pivoting doors are deployed in order to obstruct:

  1. Both fan flow and primary flow
  2. The engine primary duct and flow
  3. The fan duct and the fan flow

Question 13

The reverse system is operated with:

  1. A proper pneumatic source
  2. Independent hydraulic source
  3. The same hydraulic source

Question 24

The thrust reversers are maintained in the stowed position by means of:

  1. The isolation valve located in the Hydraulic Control Unit (HCU)
  2. Four primary locks and internal mechanical locks in the actuators
  3. Hydraulic pressure controlled by the isolation and directional valves, located in the HCU

Question 63

About the reverser system. What happens if at least one pivoting door is detected unlocked?

  1. The engine power cannot be increased
  2. The auto restow mechanism will close the pivoting door
  3. An amber REV indication appears above the N1 digital indication

Question 67

The HCU is located:

  1. In the right reverse cowl, upper side
  2. In the left reverse cowl, lower side
  3. In the pylon

Question 72

If an amber REV indication appears above the N1 digital indication:

  1. The HCU pressure switch did not detect hydraulic pressure
  2. At least one pivoting door is unlocked
  3. All stow switches detect reverse unlocked

Additional Systems and Components

Question 59

The CFM56-5B engine can obtain the maximum thrust up to:

  1. 30ºC
  2. 20ºC
  3. 15ºC

Question 62

The ECU is cooled by:

  1. Dedicated cooling blower
  2. Ram airflow
  3. Intermediate airflow

Question 71

Which of the following conditions is not an inhibit to FRV operation:

  1. Anti-Ice (A/I) selected
  2. Take-Off Go-Around (TOGA)
  3. IDLE

Question 73

The servo fuel heater unit:

  1. Has a bypass valve
  2. Does not have a bypass valve
  3. Has a bypass and relief valve

Question 74

The HPT ACC system uses HPC bleed from:

  1. Stages 4 and 9
  2. Stages 5 and 9
  3. Stages 3 and 8

Question 76

The scavenge oil to the servo fuel heater is monitored by:

  1. An electric Master Chip Detector and must be monitored locally
  2. An electric Master Chip Detector that sends its signal to ECAM
  3. A clogging indicator

Question 85

The ECU is cooled by:

  1. Fan airflow
  2. Dedicated cooling blower
  3. Intermediate airflow

Question 93

The purpose of the HPTACC is:

  1. To warm the four rotor disks of the lower pressure compressor
  2. To cool each rotor disk blade of the high turbine
  3. To cool the external case of the high-pressure turbine

Question 94

The forward sump is the location of:

  1. Bearing 1-2-3b and 3r
  2. Bearing 1-2-3 and 4
  3. Bearing 1-2-3b