Construction And Operation

Question 1

What are the 3 types of fuel tank

Answer 1

Integral
Auxiliary
Flexible (bladder)

Question 2

Define integral fuel tank

Answer 2

primary aircraft structure usually a wing or fuselage, that is sealed to contain fuel internally.

Integral fuel tanks are the most efficient way to carry fuel

nearly all modern aircraft use this type of tank.

Question 3

Advantages of integral fuel tank

Answer 3

Uses the maximum amount of space whilst having minimum amount of weight

Less drag compared to aux tanks

Question 4

Define Aux tank

Answer 4

External fuel tank mounted under pylons or fitted inside the fuselage of an aircraft

Constructed using typical aircraft design methods

Question 5

Advantages of aux tank

Answer 5

Can be fitted or removed to increase the aircrafts fuel load/range

Can be jettisoned in flight in for emergency

Question 6

Define flexible/bladder tanks

Answer 6

Substitute for a welded tank used in both small an large aircraft

Made of neoprene rubber and stuffed into cavities inside the aircraft structure

Can be removed

Question 7

Advantage of flexible/bladder tank

Answer 7

Removable to allow for ease of inspection

Question 8

What is a tank cap

Answer 8

Fuel tank filler cap

Must be fitted with a locking device and a chain to ensure the cap in not left unattached

Question 9

What considerations are there when removing/refitting a tank cap

Answer 9

GVIN/ Careful examination for damage/serviceability

Progressive inspection required before it is fitted

Question 10

What is a surge box

Answer 10

Built around the fuel pump to prevent movement of the fuel away from the pump during flight

C130 surge boxes have one way flapper valves

Question 11

What is a baffle plate

Answer 11

Sit internally inside fuel tanks

Prevent fuel surges between tanks during aircraft manoeuvres

Question 12

Why is ventilation required in a fuel system

Answer 12

To prevent a pressure buildup or vacuum during refuelling/ de-fueling

Allows trapped air to escape to prevent pressure buildup that would otherwise result in catastrophic failure

Question 13

Outline fuel ventilation

Answer 13

When an aircraft is refuelled or defuelled a positive pressure or a vacuum would be created in the fuel tank.

To avoid catastrophic failure of the tank a vent system to atmosphere is required.

The Vent system must be checked by the maintainer during refuelling to ensure there is a steady release of air

Question 14

What is drain point?

Answer 14

A point to drain fuel from the aircraft in order to take a fuel sample

usually located on the lowest point on the tank

Question 15

What is a fuel dump

Answer 15

Dumps all the fuel in an emergency in order to reduce landing weight

Achieved using an electrically powered boost pump in each of the fuel tanks

outlet in each wing

Question 16

What is the purpose of fuel quantity indicators

Answer 16

To provide information to the pilot on the fuel quantity

Question 17

What are the three types of fuel quantity indicators

Answer 17

Float type

Capacitance type

Measuring sticks

Question 18

Outline the operation of a float type quantity indicator

Answer 18

shows the fuel level by converting the position of a float into resistance via a transmitter unit.

Question 19

Outline the operation of capacitance type quantity indicator

Answer 19

A Capacitor is a device that stores electrical energy in an electrical field.

A capacitance type indication system is generally used on larger (turbine) aircraft

used when it is necessary to know the mass of fuel rather than just its level.

Concentric metal tubes serve as capacitors and extend across the fuel tanks from top to bottom. As the
quantity in fuel changes the portion of the probe immersed in air and fuel varies. The difference in dialetric
values change the electrical capacitance of the probes and a capacitance bridge measures this quantity.

Question 20

Outline the operation of a measuring stick quantity indicator

Answer 20

Used like a dipstick for oil in your car

Question 21

What are common features of a fuel tank

Answer 21

A sump or drain at the bottom of the tank

A vent system at the high point to open to the atmosphere

Baffles fitted to prevent fuel surges and restrict movement in flight

Dump valves to jettison in emergency

Question 22

What is fuel

Answer 22

A liquid containing chemical energy that through combustion is released as heat energy and constructed into mechanical energy by the engine