ATPL BOOK Flashcards
What is a surge line?
Defines the minimum value of stable airflow that can be obtained at various engine speeds.
Running line occurs before as a buffer
What are the three variables that affect the angle of attack in the compressor?
- Speed of the intake airflow
- Compressor RPM
- Direction of the intake airflow
What prevents compressor surge and stalls?
Variable inlet guide vanes/stators
Blow off or bleed valves
Multi spool engines
What is a safety coupling?
Back up device for the negative torque system, in the event of NTS failure the safety uncouples the reduction gear from the power section.
Leads to reduce drag
How to reduce blade tip flutter?
Lower speed or by reducing RPM
What are the methods that gas generators use to control the propeller-driven by their own turbine?
Prop controller
- Integrated control of both fuel flow and rpm
- Direct control of gas generator fuel flow
- Direct control of propeller blade angle.
How does the CSU work?
The cockpit power lever selects a required blade angle for the thrust demanded. Automatic functions then adjust fuel flow to achieve the required propeller RPM
WHat determines the appropriate torque setting?
Ambient Conditions
Prop RPM
Airspeed
Turbo prop performance at low speeds?
- Performs best at low speeds before the effects of high prop tip speeds reduce propeller effenciency
- Extremely capable of producing thrust at low speeds
- Propulsive force by impairing a lesser acceleration to a larger mass of air.
What type of fuel does all jets use?
kerosene
liquid hydrocarbons
Refinery fuel qualities?
- Ease of flow
- Ability to start
- complete and rapid combustion under all conditions
- Highest possible calorific value
- non-corrosiveness
- lubrication
- minimal fire hazard
What would fuel with a high specific gravity mean?
The fuel will have more mass per unit.
What is a fuel shut-off valve?
Allows fuel supply to the engine to be terminated in the event of a engine malfunction.
What do boost pumps do?
Draw fuel to the delivery lines for the engine.
Is there a bypass valve in the centre tank?
No this means if the pump fails in the cenztre tank the fuel is unusable.
What does the fuel control unit do?
Meters appropriate amount of fuel in response to thrust levers setting, measured engine speed.
What is the purpose of the fuel heater unit?
Ensures high pressure fuel is free from ice crystals, which can form in cold fuel.
What are different engine-associated instruments available to a jet engine? To represent a gas turbine engine
- N1 and N2 RPM
- Oil pressure and temperature
- Fuel Flow in high pressure delivery line
- EGT
- Engine vibrations
What are two indicators for engine power and thrust?
Engine pressure ratio gauge
Torque Gauge
Why are fuel flow gauges important?
Verify the supply of fuel to the engines on start and shutdown.
Can work with the FMS to identify expected arrival fuel.
What is the turbine engine basic starting procedure?
- Rotate the engine core with a starter untill a specified engine speed is reached
- Activate igniters
- Open the high pressure fuel supply
How is a hot start indicated?
Engine temperature rising rapidly to set limit.
How does a hung start occur?
High temperature accompanied by low RPM
Normally due to the excessive back pressure through the compressor stages.
What is the remedy for a hot and hung start?
Terminate ignition and fuel and continue cranking the starter to clear the fuel.
How can a flameout occur?
When idle rpm is set below self-sustaining rpm, and the throttle is closed in flight.
How is the air turbine starter rotated?
Compressed air is delivered normally by an auxiliary power unit.
Compressed air for the other engines start is normally tapped from a bleed air supply from the first engine.
How is reverse thrust restricted from deployed
Squat switches or wheel speed transducers, there are high-speed limitations of reverse thrust as well.
What is an artificial feel?
Power control systems have an artificial feel to prevent overstress of the aircraft, usually done by a centering spring and additional resistance to control movement.
What is q feel?
A hydraulic system that prevents over corrections provides resistance to the hydraullic operated control collums, through pitot and static pressures.
In the event of a power control failure what redundancy systems are in place.
Multiple hydraulic jacks driven from separate hydraulic systems. each hydraulic system will have its own power source.
Manual revision is also available
What is lift augmentation devices’ purpose?
To give an additional lift to the wing.
What are the types of lift augmentation devices fitted to jet transport aircraft?
Trailing edge flaps, leading-edge flaps, and slats
Explain trailing edge flaps?
- Increases camber of the wing
- Increase total wing area
- Hydraulically actuated
- Move CP rearward which therefore nose-down moment giving steeper approaches
- Lift increase
- Drage increases
- Slots can be involved to further energize airflow
Purpose of the rudder ratio changer?
Receives inputs from the air data computer and provides control signals to the actuator, then the actuator then dampens the inputs to the rudder.
Explain yaw dampeners?
There are two yaw dampeners operating continuously inflight (left and right). They are powered by the centre and left the hydraulic system, if one of the hydraulic systems is failed the yaw dampening is halfed.
What are three stabilizer trim controls?
Electric
Alternate
automatic
How is electric trim operated?
Each pilot has dual electric trim switches mounted on each control wheel., they must be pressed simultaneously to operate.
How is alternate trim operated?
Provides back up to pitch trim, alternate stabilizer trim switches are provided, and similar to the electric trim must be pressed at the same time.
Explain automatic trim?
Trim controlled by the autopilot
What is the purpose of an alerion lockout (inhibit system) ?
Permits full travel of the outboard alerions at low speeds, but at high speeds they are locked and controls for roll are off inboard alerions.