LESSON # 3

Question 1

Fuel from the LP Fuel filter passes to the (?) depending on RPM and FCU in the region of 600-800 psi. This HP fuel is then fed to the fuel control unit (FCU).

Answer 1

HP Pump/ High Pressure Pump

Question 2

The (?) will meter the engines fuel requirements based upon a given set of conditions at any given time.

Answer 2

FUEL CONTROL UNIT (FCU)

Question 3

Engines fuel requirements based upon a given set of conditions at any given time:

Answer 3

A. Throttle position.
B. Ambient Pressure (Pamb)
C. Ambient Temperature (T12)
D. HP Compressor RPM (N2)
E. Compressor Discharge Pressure (CDP)

Question 4

Fuel in excess of that required is returned to the (?) of the HP pump.

Answer 4

inlet side

Question 5

Metered fuel is then fed to the (?) via a throttles and HP cock.

Answer 5

flowmeter

Question 6

The (?) can be a combined throttle and HP cock
lever or separate levers.

Answer 6

Fuel Control Operating Levers

Question 7

The position of the (?) determines the power required.

Answer 7

Throttle Lever

Question 8

The (?) controls the supply of fuel from the FCU to the burners, when closed the engine will be shut down, when open fuel will be available to the burners.

Answer 8

HP Shutoff Cock/ High Pressure Shutoff Cock

Question 9

2 TYPES OF HEAT EXCHANGER

Answer 9

1. FUEL/AIR HEAT EXCHANGER
2. FUEL/OIL HEAT EXCHANGER

Question 10

Similar to the heat exchanger used to heat the fuel, this heat exchanger will use the HP fuel supply to cool the engine oil.

Answer 10

FUEL/OIL HEAT EXCHANGER

Question 11

Prevent fuel flowing to the burners during the starting phase until such time as fuel pressure is sufficient to give good atomisation of the fuel thus ensuring good light-up.

Answer 11

PRESSURISING AND DUMP VALVE

Question 12

Allow sufficient pressure to build up within the Fuel Control Unit (FCU) servo/hydraulic control systems ensuring correct metering of fuel supply is achieved during starting.

Answer 12

PRESSURISING AND DUMP VALVE

Question 13

Enable a rapid dump of fuel remaining in the pipelines to the burners on shutdown.

Answer 13

PRESSURISING AND DUMP VALVE

Question 14

From the fuel/oil heat exchanger HP metered fuel passes to the
pressurising and dump valve. Its function is to:

A. Prevent fuel flowing to the burners during the starting phase
until such time as fuel pressure is sufficient to give good
atomisation of the fuel thus ensuring good light-up.
B. Allow sufficient pressure to build up within the Fuel Control
Unit (FCU) servo/hydraulic control systems ensuring correct
metering of fuel supply is achieved during starting.
C. Enable a rapid dump of fuel remaining in the pipelines to the
burners on shutdown

Answer 14

PRESSURISING AND DUMP VALVE