Fuel / Hydraulics / Ice and Rain Flashcards
What subsystems does the fuel system usually consist of?
Storage and Fuel Ventilation Fuel feed Refueling / Defueling FQIS Fuel Jettison Longitudinal Trim
Where are fuel tanks located?
Wings, Fuselage and Horizontal Stabilizer
Where in a tank would you find fuel sumps and drains?
At the lowest point
What are tanks fitted with to prevent fuel surges due to altitude change and turns?
Baffles
What is the most commonly used type of fuel tank on large transport aircraft?
Integral
What are the most common methods of sealing fuel tank panels?
O-Rings and Gaskets
Why are fuel tanks ventilated?
To prevent structural damage
How large must the expansion space of a fuel tank be?
Not less than 2% of the tank capacity
Why is tank draining carried out?
To remove sediment and fuel residue from the tank. Also to remove water from the tanks to prevent freezing.
Why is it sometimes necessary to use vacuum apparatus in tank draining?
When the drain valve is not located at the tanks lowest point.
Why are drain valves fitted with a check valve?
It means the assembly can be replaced if leaking without the need of draining the fuel tanks.
What is a rule to properly drain any existing water from a fuel tank?
The tanks must be left to settle for a certain period of time
What sis the main advantage of a ‘fuel pump canister’
It can be removed without the need to drain the tanks
Which component isolates the engines in the case of engine failure?
Low pressure shut off valves
In what tanks would you find jet pumps?
In vent surge tanks or Centre tanks where no direct fuel feed to the engine takes place.
What is the purpose of an Air Release Valve?
It releases air trapped in the fuel feed line. Installed at the highest point of the fuel line
It is a requirement that fuel can be transferred between tanks. In which cases does this become necessary?
If the fuel supply of a main tank to its engine stagnates
What is a meant by the term ‘Probe’?
A measuring device that consists of 2 concentrically mounted tubes in open connection to the tank. These tubes form the plates of a capacitor.
What is the variable in the tank that affects the dielectric constant?
The ratio of fuel to air
In what case would you use the dipstick method to measure fuel level?
When there is no electrical power available
The fuel dump system is also called the?
Fuel Jettison System
What is fuel dump used for in aviation?
To bring the aircraft to a safe landing weight or go around weight.
What are some warning provided by the fuel system?
Tank Level (High and Low), System Components Inop, Fuel Imbalance, Impossible Fuel Transfer.
What is the most common type of hydraulic fluid?
Skydrol
What are the most important systems that Hydraulics supplies?
Flight Controls and Landing Gear
Why are Hydraulic tanks pressurized?
To prevent frothing and ensure there is a supply always available.
What are the two types of hydraulic accumulators?
Spherical and Piston
Main hydraulic pumps are usually of the ………………………. type?
Variable Piston Pump
What is the purpose of a hydraulic fluid reservoir?
- Have a supply of fluid available
- Absorb differences in level when in use
- Let fluid cool off, settle and release vapor bubbles
In depressurized mode the wobble plate is in the ……………. position?
Angled
What is another name for a maintaining valve?
A priority valve
3000psi is equivalent to …….. Bar?
210
What is the first component in the pressure line from the EDP?
A switch to warn if pressure is too low
Never operate a hydraulic system with pressure released in the …………. ?
reservoir
What type of pumps are hydraulic electrical pumps?
Gear type or Variable Piston
What two parts does a PTU consist of?
Motor and a Pump
How much fluid is transferred when the PTU is in operation?
None
When is a PTU is automatic mode?
In flight and on the ground
At what percentage roughly are hydraulic pressure relief valves operated?
10-20%
What are the two types of hydraulic fluids?
Mineral and Synthetic
What fluid is skydrol?
Phosphate ester
How is the fluid filter element monitored?
A differential indicator
what Colour is the band on a hydraulic seal?
Green
At what pressure will a check valve operate?
15-20 PSI
What hydraulic parameters are usually indicated in the cockpit?
Temp, Pressure, Output pressure and Quantity
What are the effect of ice on the forces of an aircraft?
Drag and Weight increases while Lift and Thrust reduces
Frost is removed from an aircraft by spraying it with a mixture of?
Ethylene Glycol + Isopropanol Alcohol
What is the purpose of an ice detection spotlight?
To illuminate parts of the aircraft that are prone to icing so the crew can visually monitor it
When is it allowed to apply chemical rain repellent to the windshield?
Only when then windshield is wet otherwise it will smear
Ice will only form on an aircraft when?
flying through cloud or precipitation where the water droplets are super cooled
What type of ice freezes immediately on impact and has a rough and generally opaque formation?
Rime Ice
what type of ice takes a while to freeze so contains air bubbles and has time to run back?
Gleam Ice
What type of ice forms in the air in small crystals and can cause blocking of intakes in sufficient volume?
Dry Ice
What type of ice is cooled slowly and so runs back in a clear smooth fashion?
Clear or Glaze Ice
Where is the ‘Wheel Base’ measured from?
From the centre of the boogie beam from NLG to MLG
Where is the ‘Wheel Track’ measured from?
From the centre of the boogie beam from left to right main landing gear
During landing kinetic energy is transferred into?
Heat energy
When 4-6 wheels are connected to a landing gear they are connected to?
Boogie beams and gear trucks
What is the function of the fluid inside the strut?
Slows down the strut movement during the extension od the shock absorber
In what part of the gear would you find fluid and nitrogen?
In the strut combined within the shock absorber
What other sub-systems are in the landing gear system?
- The brake system- The NWS system- The flight/ground switching system
Is it possible to move the landing gear handle on the ground?
yes
How does the emergency landing gear extension system work?
From a handle in the flight deck the gear can be manually unlocked via control cables. Gravity allows the gear to fall and bungee springs hold it in the locked position.
What is the purpose of the brake control valve?
The brake control valves control the pressure on the brakes and make sure there is sufficient braking force.
For what purpose are flow limiter or fuses responsible in a brake system?
They are used to prevent all brakes from becoming powerless if one of the brakes or brake lines leak. They will shut off further pressure so not all pressure is lost.
What is the function of the anti-skid system?
The anti-skid measures the deceleration of the wheels, if the wheels de-accelerate too much then the brake pressure will decrease.
Explain how a parking brake works on a typical airliner?
It is done either by pressing pedals all the way down with the help of the parking brake leaver or electrically by opening a valve supporting hyd pressure direct to the brakes.
What does shimmy mean?
the undesirable unsteadiness of the gears.
What is used to prevent shimmy?
A spring operated accumulator is installed between the torque link assembly.
What is the purpose of a ground shift mechanism?
It is a mechanical system to indicate when the aircraft is on the ground or the gear is under pressure
What kind of wheel rims are used on an aircraft?
Aluminium alloy rims in the split hub style with an o-ring between to prevent nitrogen leakages.
What is meant by re-treading?
Method of restoring a used retreadable tire by renewing the tread alone or by renewing the tread plus the reinforcing ply
Where does the centre of gravity lie when the aircraft is on the ground?
Always between the landing gears
What is being developed to keep the pressure on the runway as low as possible?
Landing gears are being developed with more and more wheels.
Down lock springs are also called?
Bungee Springs
What will a brake adjuster do?
Adjust the brakes according to wear
What is the advantage of carbon brakes?
They have a constant output whether hot or cold and are not susceptible to thermal shock
What is installed to move the rotor vanes of brakes when the wheels are turning?
Splines
What mechanism locks the gear when extended?
Over centre links
What should be used when inflating a newly fitted tyre?
A safety cage
What are the two types of tyres?
Radial and Bias
What type of bearings are used in aircraft wheels?
Conical roller bearings
What does the amber light on a landing gear panel indicate?
Wheel well doors are not closed
What does a light out on the Landing Gear panel mean?
Gear and doors are up and locked closed
What does a green light on the Landing Gear panel in the flight deck indicate?
Landing gear is down and locked
A valve that allows the Gear Up or Gear Down movement to happen in the right order is?
Sequence Valve
When is the nose wheel steerable?
When the nose gear shock absorber is compressed (on the ground)
What is the pressure called inside a strut?
Pre-Charge
What is the percentage of oxygen in the air?
21%
What is the normal way to prevent hypoxia in an aircraft?
Pressurise the cabin
Chemical oxygen generator systems are normally provided for?
Passengers in failure of the pressurisation system or insufficient cabin air flow
What is the function of the LP supply valve in the crew oxygen system?
To allow of shut off the oxygen control to the distribution manifold
How is the crew oxygen cylinder protected from over pressure?
By a rupturing pressure relief valve that releases oxygen overboard through a discharge line
The amount of time during which a pilot is able to effectivley or adiquatly fly is aircraft with insufficient oxygen is?
Effective Time Performance
Oxygen cylinders can be made from?
Steel, Aluminium or Composites
What is the purpose of the crew oxygen pressure regulator?
To step the bottle pressure down from 2200 PSI to around 20-75 PSI
The cabin altitude at which masks will be automatically released is?
14000 Feet
What is the purpose of a pneumatic isolation valve?
To split OR connect different pneumatic systems
Which component is responsible for pneumatic temperature control?
Fan Air Valve - this supplies cool engine air.
Where is air taken from to cool the pneumatic air in the heat exchanger?
Fan Cooled Air
The over pressure valve protects the users if air is provided from?
The engine HP or LP compressor stage.
What is the purpose of the HP control valve?
It is used to determine the source of engine compressor stage
Why is important to energise the aircraft prior to pressurising a pneumatic system from external?
Pneumatic systems may start unwanted or unprotected
What are pneumatic sources in flight?
Engine and APU
Pneumatic operated systems should not be supplied with cold pneumatic air from external, why?
Otherwise icing of valves or turbines may occur
In what ways can pneumatic leak detection be carried out?
- Thermal Switches- Manifold failure loops- Pressure switches.
Where is the ‘Wheel Base’ measured from?
From the centre of the boogie beam from NLG to MLG
Where is the ‘Wheel Track’ measured from?
From the centre of the boogie beam from left to right main landing gear
During landing kinetic energy is transferred into?
Heat energy
When 4-6 wheels are connected to a landing gear they are connected to?
Boogie beams and gear trucks
What is the function of the fluid inside the strut?
Slows down the strut movement during the extension od the shock absorber
In what part of the gear would you find fluid and nitrogen?
In the strut combined within the shock absorber
What other sub-systems are in the landing gear system?
- The brake system- The NWS system- The flight/ground switching system
Is it possible to move the landing gear handle on the ground?
yes
How does the emergency landing gear extension system work?
From a handle in the flight deck the gear can be manually unlocked via control cables. Gravity allows the gear to fall and bungee springs hold it in the locked position.
What is the purpose of the brake control valve?
The brake control valves control the pressure on the brakes and make sure there is sufficient braking force.
For what purpose are flow limiter or fuses responsible in a brake system?
They are used to prevent all brakes from becoming powerless if one of the brakes or brake lines leak. They will shut off further pressure so not all pressure is lost.
What is the function of the anti-skid system?
The anti-skid measures the deceleration of the wheels, if the wheels de-accelerate too much then the brake pressure will decrease.
Explain how a parking brake works on a typical airliner?
It is done either by pressing pedals all the way down with the help of the parking brake leaver or electrically by opening a valve supporting hyd pressure direct to the brakes.
What does shimmy mean?
the undesirable unsteadiness of the gears.
What is used to prevent shimmy?
A spring operated accumulator is installed between the torque link assembly.
What is the purpose of a ground shift mechanism?
It is a mechanical system to indicate when the aircraft is on the ground or the gear is under pressure
What kind of wheel rims are used on an aircraft?
Aluminium alloy rims in the split hub style with an o-ring between to prevent nitrogen leakages.
What is meant by re-treading?
Method of restoring a used retreadable tire by renewing the tread alone or by renewing the tread plus the reinforcing ply
Where does the centre of gravity lie when the aircraft is on the ground?
Always between the landing gears
What is being developed to keep the pressure on the runway as low as possible?
Landing gears are being developed with more and more wheels.
Down lock springs are also called?
Bungee Springs
What will a brake adjuster do?
Adjust the brakes according to wear
What is the advantage of carbon brakes?
They have a constant output whether hot or cold and are not susceptible to thermal shock
What is installed to move the rotor vanes of brakes when the wheels are turning?
Splines
What mechanism locks the gear when extended?
Over centre links
What should be used when inflating a newly fitted tyre?
A safety cage
What are the two types of tyres?
Radial and Bias
What type of bearings are used in aircraft wheels?
Conical roller bearings
What does the amber light on a landing gear panel indicate?
Wheel well doors are not closed
What does a light out on the Landing Gear panel mean?
Gear and doors are up and locked closed
What does a green light on the Landing Gear panel in the flight deck indicate?
Landing gear is down and locked
A valve that allows the Gear Up or Gear Down movement to happen in the right order is?
Sequence Valve
When is the nose wheel steerable?
When the nose gear shock absorber is compressed (on the ground)
What is the pressure called inside a strut?
Pre-Charge
What is the percentage of oxygen in the air?
21%
What is the normal way to prevent hypoxia in an aircraft?
Pressurise the cabin
Chemical oxygen generator systems are normally provided for?
Passengers in failure of the pressurisation system or insufficient cabin air flow
What is the function of the LP supply valve in the crew oxygen system?
To allow of shut off the oxygen control to the distribution manifold
How is the crew oxygen cylinder protected from over pressure?
By a rupturing pressure relief valve that releases oxygen overboard through a discharge line
The amount of time during which a pilot is able to effectivley or adiquatly fly is aircraft with insufficient oxygen is?
Effective Time Performance
Oxygen cylinders can be made from?
Steel, Aluminium or Composites
What is the purpose of the crew oxygen pressure regulator?
To step the bottle pressure down from 2200 PSI to around 20-75 PSI
The cabin altitude at which masks will be automatically released is?
14000 Feet
What is the purpose of a pneumatic isolation valve?
To split OR connect different pneumatic systems
Which component is responsible for pneumatic temperature control?
Fan Air Valve - this supplies cool engine air.
Where is air taken from to cool the pneumatic air in the heat exchanger?
Fan Cooled Air
The over pressure valve protects the users if air is provided from?
The engine HP or LP compressor stage.
What is the purpose of the HP control valve?
It is used to determine the source of engine compressor stage
Why is important to energise the aircraft prior to pressurising a pneumatic system from external?
Pneumatic systems may start unwanted or unprotected
What are pneumatic sources in flight?
Engine and APU
Pneumatic operated systems should not be supplied with cold pneumatic air from external, why?
Otherwise icing of valves or turbines may occur
In what ways can pneumatic leak detection be carried out?
- Thermal Switches- Manifold failure loops- Pressure switches.
