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Fuel One Flashcards

(98 cards)

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1
Q

Aviation fuels divided into network categories

A

Aviation gasoline - used for piston engine aircraft

Aviation turbine fuel - used for gas turbine powered aircraft

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2
Q

Calorific values

A

Amount of heat released when a unit mass of fuel is burned and measured in heat units KJ is called the calorific value of fuel

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3
Q

Calorific values what’s better heat or not much heat

A

More heat is better = more power

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4
Q

How is Volatility measured

A

Volatility is measured by the ability of fuel to mix readily with warm or cold air to form a combustible gas

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5
Q

What is volatility

A

Tendency of substance to evaporate at normal temperatures

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6
Q

Specific gravity

A

Used to define the weight or density of a liquid ( usually compared against water )

Water has sg od 1.0
AVgas has sg of 0.69 so would float on top

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7
Q

Approved aviation fuel

A

AVTUR - aviation kerosene type fuel
AVTAG - Wide cut ( mix of gasoline and kerosene )
AVCAT - kerosene type fuel but with a higher flashpoint. Usually used in carriers
AVGAS - gasoline type designed for piston engines

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8
Q

What is used for anti icing additives

A

Fuel system ice inhibitor ( FSII )

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9
Q

Fuel identification

A

-Marlings painted upon the fuel containers and refuelling vehicles
( Colour bands letters and figures )

Code number

F - identifies its a fuel

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10
Q

F34
F35
F40
F44

A
  1. White on black
  2. White on black
  3. Green on black
  4. Yellow on black
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11
Q

Two types of fuel systems

A

The airframe fuel system -
responsible for the storage of fuel
Delivers fuel in quantities appropriate to the power demand
Sets pressure and quality

The engine fuel system -
Adapts the fuel supplied from the airframe fuel system into the form sutaible for ignition within the engine

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12
Q

Design and disposition

A

Are dependent on the aircraft type and role and therefore the priority for space

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13
Q

Desgin needs to take into account the following in design :

A

Rapid and safe fuel replenishment
Flexibility to provide for extensions in range and endurance
Automatic or semi automatic control and management
Tolerance to flight manoeuvre and damage
Secondary use of fuel eg as a coolent

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14
Q

Fuel is stored in tanks what are the 3 types

A

Integral - part of the aircrafts structure
Metal - rigid
Flexible fabric membrane - bag tanks

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15
Q

Where is the Transport fuel tanks

A

Generally situated in the wings

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16
Q

Where is the Combat aircraft fuel tanks

A

Are in the wings and centre fuselage

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17
Q

To extend range of the aircraft

A

Two auxiliary tanks can be installed

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18
Q

They need to maximise amount of fuel in flight
Where can they store fuel

A

So they basically have fuel everywhere in the plane

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19
Q

Rigid fuel tanks

A

Metal Lightweight structure which is strengthened by internal stiffener and baffles

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20
Q

Integral fuel tanks

A

Formed by the aircrafts structure
Care must be taken during construction so there’s no corrosion

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21
Q

Flexible fuel tanks (bag tanks)

A

Needs access ports

The walls of the bag are usually fitted to the compartment walls by a stud

The bag expands when filled and WEIGHT IS CARRIED BY THE AIRCRAFT STRUCTURE

Can withstand a large amount of distortion or shock loading

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22
Q

Self sealing coverings

A

Reduce leak

They are made from layers of cellular rubber with an overall protective cover

Immediately affected by contact - swells on contact with the fuel and forces its way into the puncture to block the hole and reduce the leak

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23
Q

For ease of control and system integrity what is usually done

A

Arranged in groups

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24
Q

On multi engine aircraft

A

Fuel from each group feeds specific engine
Facility to transfer fuel to other engines or tank groups is provided ( covered later )

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25
Collector tank
Each tank in a group feeds fuel through pipes or galleries into a collecotr tank which is always full of fuel Collector tank feeds engine directly Ensures an uninterrupted supply of fuel to each engine
26
Fuel tank pressurisation and venting system Fuel tanks can be :
Unpressurised ( open to atmosphere ) Pressurised with air
27
What must be done when fuel level in a tank reduces
Space above the fuel must be replaced with air otherwise a vacuum will be created slowing the flow of fuel and possibly causing tank damage
28
Effects of altitude as it increases
Atmospheric air pressure decreases Boiling point of all liquids decrease Excessive fuel vapours would be produced increasing the risk of fire and loss of fuel due to evaporation
29
Aircraft designed to fly at high altitude
Needs to be pressurised
30
Aircraft that fly at low altitudes will not be affected so only needs unpressurised
31
Unpressurised tanks and components
- Are open to atmospheric pressure via pipework ALLOWS: - inward venting of air when fuel level is lowering Outward venting of air when the fuel level rises in the tank
32
What does a air/no fuel vlave do
Allows plane to fly upside down It's fitted to the top of the tank and allows air into and out of the tank during normal flight Prevents loss of fuel during inverted flight and aircraft climb Consists of a plastic float above a weighted ball Can be fitted to both pressurised and unpressurised tanks
33
Air/no fuel valve how does it work
During inverted flight the weighted ball is affected by the gravity and pushes the plastic float into a position to seal the tank and stop fuel escaping
34
Pressurised tanks and components advantages
Transfer - air pressure can be used as a method of transferring fuel between tanks Prevents excessive fuel vapour - pressuring the tanks increases the boiling point of the fuel and reduces the amount of vapour Reduces fire risk - reducing fuel vapour lowers the risk of fire Maintains the shape of the flexible tanks
35
Disadvantage of pressurised tanks and components
Added weight and routing complexity of additional components and pipework
36
What does a Ram and/or bleed air do
Provides air to pressurise the tanks
37
What does the non return valve do
Fitted so air is directed to the tanks and not lost overboard
38
Pressure reducing vlave
Senses changes in atmospheric pressure Opens to allow air from the engine to pressurise the tanks if they are below the lowest required system pressure Closes when pressure is reached Reopens if pressure fails
39
Outward relief valve
Spring loaded valve that opens if tank pressure reaches the highest system pressure Allows air to be relieved overboard Prevents damage from excessively high pressures in comparison to atmospheric pressure
40
Inward relief valve
Prevents cavitation (imploding like the submarine) of pressurised tanks Cavitation is more likely during steep descents when atmospheric pressure will increase rapidly
41
Fuel/No air valve
Only fitted if the pressurised tank transfers its fuel to an unpressurised tank Next tank must recieve fuel but if air was to follow after the tank was empty it would be continuisly vented to atmosphere
42
What does a Vent valve do
Depressurise the tanks Necessary before and during refueling Sometimes known as a depressurisation valve
43
Pressure switch
Provides an electrical signal to the cockpit warning indicator of low tank pressure
44
Booster pumps
Positioned in a sump (lowest part of the system) to ensure positive supply regardless of the attitude of the aircraft Can be integral or external Required before the engines have started and therefore must be power
45
Non return vlave
One direction only Towards the engine Marked with an arrow Mandatory flow check must be carried out after disturbing NRV
46
Low pressure fuel filter
Removes any foreign particles from the fuel before reaching the engine Also has a by pass because dirt fuel is better than no fuel
47
LP fuel cock
Separates airframe fuel system from the engine fuel system. It's purpose is to allow full flow or no flow at all to the engine Can be electrical or mechanical Only used to shut down engine in event of emergency Close it for engine change aswell
48
Fuel recirculation system how do we cool things
Fuel cooled oil cooler
49
Fuel cooled oil cooler
Hot oil is cooled as it flows around a series of small pipes carrying cool fuel Purpose is to maintain a sufficient flow of cool fuel through the FCOS
50
Air cooled fuel cooler
Ram air may be used Surface heat exchanger similar to a car radiator
51
Ejector (jet pump)
Will cool the hot fuel by mixing it with cold fuel prior to its return to a fuel tank. Cooled fuel then exits the ejector and flows along a connected pipe to be returned to storage
52
Temperature sensor
Fitted in the supply lines to monitor the fuel temperature The electrical signal it generates as it heats up can be used for gauges in the cockpit and automatically generate cooling air through the ACFC
53
Methods of transfer and control of fuel
Air pressure - moving fuel from tank Electric transfer - using pumps to move fuel from tank Fuel ejectors - moving fuel from tank Gravity - moving fuel from tank
54
Components for fuel tank level and transfer control
Mechanical float valve - stops the flow when a certain level is reached ( same system as your toilet ) Electrical float switches - float moves up and down. when it gets to the top a magnetic flips the switch
55
Fuel management and control
To maintain the c of g managing the transfer sequence To provide indications of various parameters and warnings of malfunctions To give the crew various options in the movement of fuel and to counter any system malfunctions
56
What's done nowadays with management and control? It's automatic. Methods of control are:
System design/layout Electrical components Mechanical components
57
Fuel flow proportioners
Mechanical device that is used to maintain balance by taking a specific amount of fuel from two or more sources and passing it to a common outlet. This is mainly automatic but can be manual but just puts more stress on the crew
58
Fuel dump ( jettison )
Because of undercarriage and structural stress constraints reaches more maximum weight and struggle For emergency you dump fuel into the ocean
59
Pipelines
Join various components in aircraft systems to permit fluid flow between them
60
Fuel identification symbols
Marked to identify the fluid they carry and where applicable the system to which they belong Direction
61
Electrical bonding
Prevents build up of static charge
62
P clips
In a run of hoses or pipes. They support along the airframe and they keep them apart from other adjacent pipework or components.
63
Flexirac couplings
Installed with AMM and must ensure that the couplings clamp does not rub against adjacent cables
64
Fuel content purpose
Provide a continuous and accurate indication to the crew of the quantity of usable on board fuel at all times
65
Fuel quantity indicating
Mass in kg or lb is indicated in preference to volume (gallons or litres) As each unit of mass contains the same amount of energy refaress of its temperature or volume Enables them to calculate the range or flight duration accuraltey
66
Fuel gauging system can provide the following indications
Total fuel system contents Contents of individual tanks or group of tanks Amount of fuel being used at any given time
67
Contents gauges
Continuous cockpit indication of total fuel quantity
68
Flaot type Fuel contents transmitter
Float actuator variable resistors are used to sense fuel levels
69
Capacitance gauging units
Made of inner and outer conductive plates Electrical capacitance of these units varies as the fuel level between the plates changes
70
Engine fuel flow
Estimates the range of flight If higher than normal may indicate a problem in engine performance
71
Fuel flow transmitter
Sense volume flow rate of fuel being consumed by the engine and transmits a electronic signal
72
Low fuel level warning
Tells you when its to low
73
Manual level measurement
Dipstick - like a car Drip stick - until it leaks Drop stick- magnet and a float
74
Fuel contamination
Fuels should only be used if they are authorised Aviation fuel should be clear and bright and contain no detectable free water or significant visible solid matter
75
Principle contamination threats are :
Foreign particulates Water -suspended water -free water
76
Microbiological organisms
Develop presenting a further risk of element clogging
77
Cross contamination
Main cause is a result of bad housekeeping
78
Water sediment checks
Water will precipitate out of the fuel when temperature drops. Water collects on aircraft fuel tanks Micro organisms form in water and causes sludges
79
Water sediment check procedure
I sample is drained from a valve located at the bottom of a tank into a transparent container Visual check can be done Cloudy sample may be evidence of water ( slimy deposits ) indicates microorganism A syringe is used to draw some of the liquid through a detection capsule. The tablet contains a yellow coloured detection paper, which will turn blue if the sample contains too much water
80
What do you do with affected tanks
Will have to be drained and the contamination investigated and removed
81
Fuel system testing
Leak checks Fuel flow test - by authorised person
82
Fuel tank maintance
Fuel tank leaks and repairs Rigid tanks - would normally require removal and specialist repair Flexible tanks- repair by the manufacturer or replaced Integral tanks - a full repair but costs alot A subsequent repair
83
Flexible tanks may be affected by
Cavity drain blockage The tank being plugged by contact with the aircraft structure Self sealing layer activation Fuel tank level Aircraft attitude Tank pressurisation
84
Fuel tank maintenance To reduce risks :
Preparation draining Venting Use of inspection lamps PPE - avoid breathing, protect the skin
85
Entering a fuel tank
1. Person must be medically examined 2. Wear a breathing apparatus 3. The intake ( free ) end of the respirator tube is positioned clear and upwind 4. The correct protective clothing is warn 5. Fire extinguishers of the correct type must be ready for use 6. A second person must act as an observer and is responsible for the safety of the operator inside the tank 7. Time in the tank must be controlled and supervised to ensure it adheres to current guidelines
86
What must you wear when going into a tank
Rubber overalls, rubber boots, rubber gloves, special head gear
87
Ground refueling operations
Open line refueling Pressure refueling
88
Open line refueling
Nozzle - gravity or overwing fueling ( like how you fill your car)
89
Pressure refuelling
Normal method used Through hoses and quick release couplings
90
Defuelling
During servicing Reduce fuel load
91
Pressure defuelling
Same as refuelling but pressure is just not as powerful. It also uses suction
92
Open line defuel
A nozzle like a car thing which sucks into the nozzle need to be careful for damage
93
Drain defuel
Drain points at the bottom of each tank
94
Liquid oxygen systems should not
be replenished during refueling operations
95
PPE whilst refuelling
Safety boots Coveralls Gloves Goggles or visor
96
Bonding requirements
Ensure that aircraft and fuel bowser are both correctly earthed
97
Rotors turning refuelling
All personnel must be authorised
98
Refueling in a hangar
It has to be authorised Ventilation and egress ( exit ) High volume fire fighting vehicle Towing vehicles and trained personnel to remove aircraft Fuel bowser located outside the aircraft Must be an obstruction-free escape route

Systems (6 decks)

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