Engine Fuel Systems

Question 1

During what period does the fuel pump bypass valve open and remain open?

Answer 1

When the boost pump pressure is greater than fuel pump pressure.

Question 2

Which of the following statements concerning a centrifugal-type fuel boost pump located in a fuel supply tank is NOT true?

Answer 2

The centrifugal-type pump is classified as a positive displacement pump.

Question 3

Where is the engine fuel shutoff valve usually located?

Answer 3

Aft of the firewall.

Question 4

Boost pumps in a fuel system…

Answer 4

provide a positive flow of fuel to the engine pump.

Question 5

(Refer to Figure 7.) What is the purpose of the fuel transfer ejectors?

Answer 5

To assist in the transfer of fuel from the main tank to the boost pump sump.

Question 6

What is the purpose of an engine-driven fuel pump bypass valve?

Answer 6

To prevent a damaged or inoperative pump from blocking the fuel flow of another pump in series with it.

Question 7

Most large aircraft reciprocating engines are equipped with which of the following types of engine-driven pumps?

Answer 7

Rotary vane-type fuel pump.

Question 8

When an electric primer is used, fuel pressure is built up by the what?

Answer 8

booster pump.

Question 9

The fuel pump relief valve directs excess fuel to the what?

Answer 9

inlet side of the fuel pump.

Question 10

Which type of pump is commonly used as a fuel pump on reciprocating engines?

Answer 10

Vane.

Question 11

The purpose of the diaphragm in most vane-type fuel pumps is to what?

Answer 11

compensate fuel pressures to altitude changes.

Question 12

The primary condition(s) that allow(s) microorganisms to grow in the fuel in aircraft fuel tanks is (are) what?

Answer 12

the presence of water.

Question 13

It is desirable that fuel lines have a gentle slope upward or downward and not have sharp curves or sharp rises and/or falls in order to what?

Answer 13

prevent vapor lock.

Question 14

The fuel systems of aircraft certificated in the standard classification must include which of the following?

Answer 14

A positive means of shutting off the fuel to all engines.

Question 15

Where is the main fuel strainer located in the aircraft fuel system?

Answer 15

At the lowest point in the fuel system.

Question 16

Where physical separation of the fuel lines from electrical wiring or conduit is impracticable, located the fuel line…

Answer 16

below the wiring and clamp the line securely to the airframe structure.

Question 17

What is a characteristic of a centrifugal-type fuel boost pump?

Answer 17

It separates air and vapor from the fuel.

Question 18

The Federal Aviation Regulations require the fuel flow rate for gravity systems (main and reserve) to be what?

Answer 18

150 percent of the takeoff fuel consumption of the engine.

Question 19

Fuel boost pumps are operated…

Answer 19

to provide a positive flow of fuel to the engine.

Question 20

A pilot reports that the fuel pressure fluctuates and exceeds the upper limits whenever the throttle is advanced. The most likely cause of the trouble is what?

Answer 20

a sticking fuel pump relief valve.

Question 21

A fuel strainer or filter must be located between the what?

Answer 21

tank outlet and the fuel metering device.

Question 22

Fuel pump relief valves designed to compensate for atmospheric pressure variations are known as what?

Answer 22

balanced-type relief valves.

Question 23

Fuel lines are kept away from sources of heat, and sharp bends and steep rises are avoided to reduce the possibility of what?

Answer 23

vapor lock.

Question 24

Fuel crossfeed systems are used in aircraft to what?

Answer 24

maintain aircraft stability.

Question 25

In an engine equipped with a float-type carburetor backfires or misses when the throttle is advanced, a likely cause is that the what?

Answer 25

accelerating pump is not operating properly.

Question 26

A fuel pressure relief valve is required on what?

Answer 26

engine-driven vane-type fuel pumps.

Question 27

A rotary-vane pump is best described as a what?

Answer 27

positive-displacement pump.

Question 28

Fuel pressure produced by the engine-driven fuel pump is adjusted by the what?

Answer 28

relief valve adjusting screw.

Question 29

Kerosene is used as turbine engine fuel because what?

Answer 29

kerosene has more heat energy per gallon and lubricates fuel system components.

Question 30

What are the principal advantages of the duplex fuel nozzle used in many turbine engines?

Answer 30

Provides better atomization and uniform flow pattern.

Question 31

It is necessary to control acceleration and deceleration rates in turbine engines in order to what?

Answer 31

prevent blowout or die-out.

Question 32

Which of the following turbine fuel filters has the greatest filtering action of any present-day filter type?

Answer 32

Micron filter.

Question 33

What is the purpose of the flow divider in a turbine engine duplex fuel nozzle?

Answer 33

Creates the primary and secondary fuel supplies.

Question 34

What causes the fuel divider valve to open in a turbine engine duplex fuel nozzle?

Answer 34

Fuel pressure.

Question 35

How often should float carburetors be overhauled?

Answer 35

At engine overhaul.

Question 36

What is the final authority for the details of carburetor overhaul?

Answer 36

The manufacturer’s recommendations.

Question 37

Excessively rich of lean idle mixtures result in what?

Answer 37

incomplete combustion.

Question 38

Which statement is true regarding proper throttle rigging of an airplane?

Answer 38

the throttle stop on the carburetor must be contacted before the stop in the cockpit.

Question 39

What precaution should be taken when putting thread lubricant on a tapered pipe plug in a carburetor float bowl?

Answer 39

Engage the first thread of the plug, then put a small amount of lubricant on the second thread and screw the plug in.

Question 40

Maximum power is normally considered to be developed in a reciprocating engine with a fuel/air mixture ratio of approximately what?

Answer 40

12:1