Chapter 3 - Engine Fuel and Control

Question 1

What does the fuel distribution system do?

Answer 1

Takes the fuel supplied by the aircraft systems and delivers the right amount of fuel to the correct injectors at the right time.

Question 2

What are the 3 main components of the FDS? (5)

Answer 2

Hydro-mechanical metering unit
Fuel valve assembly
Fuel injection system
(Combustion chamber drain, Drain collector)

Question 3

What does the HMU do and location?

Answer 3

Ensures fuel supply and fuel flow metering. It is located on the front right of module 1.

Question 4

What do the 2 fuel pumps do (as part of the HMU)?

Answer 4

High and low pressure pumps. Supply fuel at a required pressure and flow. Located on the common drive shaft.

Question 5

What type of pump is the high pressure pump HMU?

Answer 5

Gear type pump with a pressure relief valve (which can return fuel to the pump inlet).

Question 6

What type of pump is the low pressure pump HMU?

Answer 6

Centrifugal pump with a injector (supplied by fuel from the outlet to improve suction efficiency).

Question 7

What does transparent mean in regards to the low pressure pump?

Answer 7

Fuel can flow through the pump eve though it is not turning, it is also capable of sucking fuel from the tanks in case of booster pump failure.