Construction And Operation Flashcards
What are the 3 types of fuel tank
Integral
Auxiliary
Flexible (bladder)
Define integral fuel tank
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.
Advantages of integral fuel tank
Uses the maximum amount of space whilst having minimum amount of weight
Less drag compared to aux tanks
Define Aux tank
External fuel tank mounted under pylons or fitted inside the fuselage of an aircraft
Constructed using typical aircraft design methods
Advantages of aux tank
Can be fitted or removed to increase the aircrafts fuel load/range
Can be jettisoned in flight in for emergency
Define flexible/bladder tanks
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
Advantage of flexible/bladder tank
Removable to allow for ease of inspection
What is a tank cap
Fuel tank filler cap
Must be fitted with a locking device and a chain to ensure the cap in not left unattached
What considerations are there when removing/refitting a tank cap
GVIN/ Careful examination for damage/serviceability
Progressive inspection required before it is fitted
What is a surge box
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
What is a baffle plate
Sit internally inside fuel tanks
Prevent fuel surges between tanks during aircraft manoeuvres
Why is ventilation required in a fuel system
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
Outline fuel ventilation
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
What is drain point?
A point to drain fuel from the aircraft in order to take a fuel sample
usually located on the lowest point on the tank
What is a fuel dump
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
What is the purpose of fuel quantity indicators
To provide information to the pilot on the fuel quantity
What are the three types of fuel quantity indicators
Float type
Capacitance type
Measuring sticks
Outline the operation of a float type quantity indicator
shows the fuel level by converting the position of a float into resistance via a transmitter unit.
Outline the operation of capacitance type quantity indicator
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.
Outline the operation of a measuring stick quantity indicator
Used like a dipstick for oil in your car
What are common features of a fuel tank
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
What is fuel
A liquid containing chemical energy that through combustion is released as heat energy and constructed into mechanical energy by the engine
