Fuel Systems Flashcards
What is AVGAS
Aviation gasoline - used for piston engine aircraft
What is AVTUR
Aviation Turbine - Used for gas turbine powered aircraft
What is calorific value
The amount of heat released when a unit mass of fuel is burned
What is volatility
Tendency of a substance to evaporate at normal temperatures
What is specific gravity
The weight/density of a liquid compared to water
What are the 4 approved aviation fuels
AVTUR (kerosene)
AVTAG (kerosene and gasoline)
AVCAT (Similar to AVTUR but has a higher flash point)
AVGAS (gasoline)
What is FSII
Fuel system ice inhibitor
What colour code represents AVTUR
White on black
What colour code represents AVCAT
Yellow on black
What colour code represents AVTAG
Green on black
What 2 aircraft systems contain fuel
Airframe fuel system
Engine fuel system
What are the design objectives of a fuel system
Rapid fuel replenishing
Flexibility of operation (range and endurance)
Tolerance to manoeuvre and damage
Secondary uses of fuel (coolant)
Automatic or semi automatic control of system
What are the 3 types of fuel tank
Rigid
Integral (built in)
Flexible
What is the purpose of a collector tank
Fuel is fed through them from various systems, and they provide an uninterrupted flow of fuel into the engine
What is the purpose of tank pressurisation
Maintain the pressure of air above the fuel at an appropriate level
What is the effect of altitude on the fuel system
Boiling point decreases (risk of fire)
What is the purpose of unpressurised tanks
Open to atmospheric pressure to allow inward venting of air when fuel level is lowering and outward venting of air when fuel level is rising
What is an Air/No fuel valve
A valve fitted to the top of a tank that allows air in, but no fuel out during inverted flight of climbing
What are the advantages of pressurised tanks
Air pressure can be used to transfer air
Prevents excessive fuel vapour
Reduces fire risk
Maintains tank shape
What is the purpose of the LP cock
To separate the airframe fuel system from the engine fuel system
Allow full flow or none at all to the engine
Can be used in emergencies to shut down engine
Where is a booster pump positioned
In a sump to ensure supply no matter the attitude of the aircraft
What is an FCOC
Fuel cooled oil cooler
Cools hot oil as it flows around pipes containing colder fuel
Also prevents ice from forming in fuel lines
What is an ACFC
Air Cooled Fuel Cooler
Fuel is cooled before returning to the tanks and prevents damage to pipelines, sealants and stops vapour forming in the pipelines
How does an ejector work (fuel pump)
Mixes hot oil with cold fuel using pressure to draw both together
What are the 4 methods of transfer
Air pressure
Electric transfer
Fuel ejector
Gravity
What 2 components are used to monitor fuel tank level and control
Float valve
Float switch
How do self sealing coverings work
The rubber between the outer and inner layer of the tank swells on contact with fuel and closes the hole
What are the 2 types of fuel contents transmitter
Float type
Gauging unit
How is fuel quantity measured
Kilograms or pounds
What 3 indications can be given by the fuel gauging system
Total system contents
Contents of individual tanks
Amount of fuel being used at any time
What is the purpose of the fuel flow transmitter
Sense the volume of flow of fuel being consumed by the engine and transmit an electrical signal
What are the 3 manual methods of measuring the fuel level
Dipstick
Drip stick
Drop stick
What are the 5 threats to fuel
Foreign particles
Water
Microbiological organisms
Cross contamination
User responsibilities
What tests care carried out after disturbing the fuel system and the fitting of any component
Leak check
Fuel flow test
How is water collected for a sediment check
Drained from a valve in the bottom of a container, into a transparent container
How is health risk reduced during tank maintenance
Preparation draining
Venting
Inspection lamps
PPE
2nd person
What are the 2 methods of refuelling on the ground
Open line refuelling
Pressure refuelling
What are the 3 types of defuelling
Pressure defuel
Open line
Drain
What are the 4 types of PPE that should be worn during fuelling
Safety boots
Coveralls
Gloves
Goggles
What type of booster pump is used in a fuel supply system and why
Impeller pump
It can rotate constantly with zero flow, still allowing fuel to reach the engine
What 6 rules must be followed when refuelling in a hangar
Authorised
Adequate ventilation
High volume fire fighting vehicle in attendance
Suitable towing vehicles
Fuel bowser outside
Obstruction free escape route
What are the 5 bonding procedures during fuelling
Aircraft and bowser are earthed
Connect aircraft and bowser by bonding lead
Connect hose to bonding point
Connect fuelling hose and refuel
Disconnect bonding in reverse order
