AAS Flashcards
Important
Function of a starter generator system?
Book 1
- A DC motor is used in a starter generator system to start the aircraft engine
- It can then be used as a generator to supply the aircraft DC bus and recharge the battery.
- Still used in light aircraft’s where weight is a major consideration
What advantages does Bleed Air have over other starting systems?
Book 1
It has many advantages over other starting systems, and is comparatively light, simple and economical to operate
What are the main components of a typical air starting system?
Book 1
The main components of a typical air starting system are a starter motor and a start control valve.
Important
Bleed air sources - the starter motor is rotated by 3 main power sources, these are?
Book 1
- air taken from an external ground supply
- an auxiliary power unit (APU)
- bleed air from a running engine
Important
What is the purpose / function of an APU in an automatic starting system used in modern aircraft’s?
Book 1
- Forms integral part of the engine starting system
- Supply low pressure air
- Commands / controls signals to components in the engine control system
The APU supplies Low Pressure air for the air starting motor
Label the components in the Starter Circuit Diagram
Book 1
- Auxillary Power Supply Control Unit
- APU Starter Motor
- APU
- Air Starter Motor
- Turbofan Engine
What are the components of a Engine Ignition System?
Book 1
The engine ignition system supplies the electrical power necessary to operate the engine igniters during start/relight sequences.
The system includes two
high energy (HE) ignition units, two HE igniter leads and two igniter plugs.
Important
What does the Gas Turbine Start caption (GTS) indicate in the cockpit?
Book 1
The captions come on to indicate that the APU is running and ready to supply Low Pressure air
What is a “ENG START “START-ON-OFF” switch in the cockpit.
Book 1
The switch that controls the main power supply to the APU and engine starting system
What is an “IGNITION “NORMAL-ISOLATE” switch in the cockpit?
Book 1
This switch
controls the power supply to the engine ignition system
What is a “ROT” or Rotation caption in the cockpit.
Book 1
During a start/relight sequence, the captions come on to indicate that the engine low pressure
section rotating assembly is turning at more than 100 RPM (in the correct
direction).
What is the Auxiliary Power System Control Unit (APSCU)?
Book 1
The APSCU is the brains behind the starting system.
It contains components and circuits to control and monitor the APU and engine start sequences.
To control and monitor the APU and engine start sequences
What is the central component of a Jet Engine Ignition System?
Book 1
The central component of the jet engine ignition system is the High Energy
Ignition Unit (HEIU)
Where are the ignition switches located in a Jet Engine ignition system?
Book 1
The ignition and relight switches are located in the aircraft cabin, usually close to the throttles.
They connect bus voltage to the ignition relay and HEIUs
What is the purpose of
High Tension Ignition Leads in a Jet Engine Ignition System?
Book 1
The high tension ignition leads are located on the aircraft engine, connected between the
HEIUs and the igniter plugs.
They conduct the high voltage from HEIUs to the igniters
What occurs if a flame-out happens during flight?
Book 1
The engine continues to rotate due to airflow; ignition source is needed to re-ignite the fuel/air mixture
What are the four main precautions when dealing with High Energy Ignition Units (HEIU)?
Book 1
- do not touch the HEIU when operating
-
allow the recommended amount of time to elapse before
handling the HEIU or disconnecting associated circuitry - when removing the HEIU, disconnect the input plug before the output plug
- when installing the unit, connect the output plug before the input plug
Electrical isolation
Removal - Disconnect input first
Installation - Connect output first
Do not touch when operating
Allow the recommended time to elapse before touching it
A typical magneto ignition system contains what components?
Book 1
- magneto
- auxiliary starting device
- ignition switch
- ignition harness
- spark-plugs
Label the components in the Rotating Magnet Magneto
Book 1
- Secondary Winding
- Primary Winding
- Magneto Switch
- Distrubition
- Rotor
Due to the magneto producing high voltages, without an external power source. What are some safety requirements to ensure electrical safety?
Book 1
Always place the magneto ignition switch in the cockpit to the OFF
position, thus short-circuiting the contact breaker points
What is the purpose of the Auxiliary starting device?
Book 1
A fundamental weakness of all magnetos is that the strength of the spark is proportional
to the rotor speed.
It is therefore necessary to provide auxiliary means for boosting the magneto output during
the engine starting period.
i.e. It boosts the strength of the spark
What is the source of high pressure oil for the controlling the proppeller?
Book 2
In both PGM and Beta mode.
The source of high pressure oil for controlling the propeller is the propeller governor.
What is the purpose of the unfeather pump, in a propeller control system?
Book 2
The unfeather pump provides oil pressure for moving the
blades out of the feather position on the ground and for air starting the engine
What two basic modes of the propeller control system?
Book 2
- Propeller governing mode (alpha range or flight range)
- Beta mode (ground range).
What is the differnece between Propeller governing mode and Beta mode?
Book 2
In the propeller governing mode, the governor itself varies the oil pressure
to in turn vary the pitch of the blades to maintain the pilot
selected RPM.
In the beta mode the propeller governor
provides the oil pressure and the pilot manually varies the
pitch control to change the blade angle.
In which mode does the Power lever (when retarded) controls the propeller blade angle directly?
Book 2
In Beta Mode, the Power Lever, when retarded behind the flight idle gate, controls the propeller blade angle
directly.
How do we know that the propeller is at a pitch that corresponds to ground operations?
Book 2
The corresponding increase in oil pressure also triggers a light on the annunciator panel indicating that the propeller is at a pitch which corresponds to ground operations (BETA MODE)
A Propeller synchrophaser target, where is it installed?
Book 2
A propeller synchrophaser target is installed on the de-icing platter located immediately
adjacent to the back of the propeller
What is the purpose of the Negative Torque System (NTS)?
Book 2
NTS is a system that senses when the air load on the propeller
starts to drive the engine.
The NTS will reduce propeller drag in the event of drag caused by
selection of ‘flight idle’ during descent
What does the NTS light indicate?
Book 2
The NTS light will illuminate when oil pressure in the propeller control system rises above a pre-set value
NTS stands for Negative Torque Sensing.
What does the speed of the slave engine do?
Book 2
Follows changes in the speed of the master engine over a predetermined limited range
This indicates a dependent relationship between the slave and master engines in terms of speed regulation.
Label the components
Book 2
- Beta Switch
- NTS Switch
- Unfeather Pump
- Torque Sensor
- Proppellor Governor
- Feather Valve
- Pitch Control
- Propellor
What voltage is Linear Variable Differential Transformer (LVDT) supplied with?
And what is the output amplitude and phase proportional with?
Book 3
The Linear Variable Differential Transformer (LVDT) is supplied with
an AC input voltage.
The output amplitude and phase is
proportional to the actuator displacement and the direction
of displacement.
The servo unit LVDT sends positional feedback to the flight control computer
Fill in the blanks
(——-) servomotors are usually (———) induction motors
Book 3
AC servomotors are usually two phase induction motors.
Where do you get pressure (air) in a Electro-Pneumatic system?
Book 3
The valves are controlled by electrical command signals from
the autopilot-signal processing element and the pressure
for actuation of the pistons is either from an engine-driven
pump or from a tapping at one of the turbine engine
compressor stages
How is attitude sensed by the aircraft?
Book 3
The aircraft moves in attitude which is sensed by the attitude and rate
sensing elements. This is a form of feedback
Attitude describes the airplane’s orientation relative to the horizon
Label the components
Book 3
- Attitude and Type
- Control Colomn Transduceer
- Flight Control Computer
- Airspeed Attitude
- Servo Unit
- Control Surface
Servo unit LVDT sends positional feedback to the flight control computer
What does this display indicate?
Book 4
A striped display, often termed a barber’s pole (displayed only when
the landing gear is ‘in transit’ or when electrical power is off)
What does this display indicate?
Book 4
A diagram of a miniature wheel (displayed only when the landing
gear is ‘down and locked’)
What are the following terms in anti skid operations?
- Slip
- Skid
- Aquaplane
Book 4
- Slip describes a wheel that has not locked up completely.
- Skid describes a wheel that is locked up completely and not rotating
-
Aquaplane is locking the wheels up on a wet
surface, causing the wheels to ride on a film of water.
What is Fail-Safe Protection in a skid control system?
Book 4
The fail-safe protection circuit inside the skid control box monitors the
operation of the skid control system.
It automatically returns the brake system to full manual operation if the system fails and illuminates a
warning light.
What is the “Unsafe conditon” of the landing warning system in a aircraft?
Book 4
The landing warning system warns the aircrew
if the aircraft is attempting to land without the
undercarriage fully extended and locked.
In the Landing Warning System, what makes the Differential Pressure Switch close?
Book 4
The differential pressure switch will close whenever the airspeed falls below a predetermined level (this speed will vary for different
aircraft types)
What is the “In-Transit
Warning” in a aircraft landing warning system?
Book 4
The warning lights within the handle of the landing gear control lever flash whenever the
undercarriage is not in the same position as selected by the landing gear control lever
An aircraft undercarriage safety circuit is designed to ensure that…
Book 4
Landing-gear control systems usually incorporate some form
of safety circuit to ensure that the landing gear cannot be
retracted when the aircraft is on the ground
In an anti-skid brake system, the ski control valve relaxes the brake application by:
This solenoid’s action lowers the pressure in the line between the metering valve and the brake cylinders. It does
this by dumping fluid into the reservoir return line whenever
the solenoid is energised.
What is the Ground Safety Micro Switch in a Electrically Controlled Landing Gear System
Book 4
A ground safety micro switch is used to prevent accidental retraction of the landing gear while the aircraft is on the ground.
What does the compression of the undercarriage strut do when the weight of the aircraft is on the wheels?
Book 4
Holds the contacts of a Weight on Wheels (WOW) micro switch open
This refers to a safety mechanism in aircraft design that prevents certain systems from being activated when the aircraft is on the ground.
What are the locations of the three following colours with regards to Navigation lights?
- Green
- Red
- White
Book 5
- Green light located on the starboard (right hand) wingtip
- Red light located on the port (left hand) wingtip
- White light located on the rear of the aircraft (tail).
There is Red Port Left
What is the frequency of Anti collision lights on an Aircraft?
Book 5
They are a high intensity red or white light that flashes on and off at a
typical frequency of 80 - 90 cycles per minute
What is the frequency of Strobe lights on an Aircraft?
Book 5
70 times per minute
Label the component
Book 5
- Strobe Power Supply
What type of panel is this?
Book 5
Trans-Illuminated Panel
Trans-illumination (sometimes known as edge lighting) is a
method used to illuminate etched inscriptions on cockpit
panels to make them readable under night conditions.
What is Flood-Lighting used for in a aircraft?
Book 5
Flood-lighting is used for the general illumination of
instruments, control panels, pedestals, side consoles and
areas of the cockpit floor
What are dome lights in a aircraft?
What colour are they?
Book 5
They are a type of flood-light and are usually situated overhead to illuminate an area such as: the cockpit,
passenger, cargo, or galley area.
Dome lights can usually be selected to provide white light.
What type of lighting is in this picture?
Wedge type intergral lighting
What are the Mandatory Requirements of thermocouples (Fire Detection systems)
Book 5
- Require a minimum of electrical power and operate from the aircraft electrical system
without inverters or other special equipment - are durable and resistant to damage from all of the environmental factors which may exist
in the location where it is installed - include an accurate and effective method for testing to ensure the integrity of the system
- are easy to inspect, remove and install
- are designed so the possibility of false indications is unlikely
- accurately indicate that a fire has been extinguished and indicate if a fire re-ignites
Label the component
Book 5
Thermostatic Detectors
How must Gravity fed systems be designed?
Book 6
Gravity-fed systems must be designed with the fuel tank
placed a sufficient distance above the carburettor to provide
150% of the fuel flow required for take-off operation
Label the components in the fuel system
Book 6
- Engine Fuel shutoff valve
- Engine Fuel shutoff valve
- Boost Pump
What is the basic requirement of an aircraft fuel system?
Book 6
Clean fuel under a positive pressure at all aircraft attiudes and altitudes
What are boost pumps used for in a fuel system?
Book 6
Boost pumps are used to move fuel through the fuel system when gravity flow is insufficient.
On a fuel boost system, what is the purpose of the selector valve?
Book 6
Selector Valve
The function of fuel selector valves, sometimes called ‘fuel cocks’, is to:
* provide a means of shutting off the fuel flow
* select the tank in a multiple-tank installation
Fuel pressure must be monitored at various points in the fuel system to inform the flight crew if a problem exists. How do they do this?
Book 6
Fuel low pressure switches will alert the crew via the central warning
system or individual panel lights that a low pressure condition exist
In a Air Condition System in a Aircraft, what are the following air types?
Ram Air
Bleed Air
Conditioned Air
Book 7
-
Ram air is introduced into the aircraft through forward
movement of the aircraft. -
Bleed air can be used for de-ice, anti-ice, cabin
pressurisation, heating and cooling systems -
Conditioned air is air that has been treated so its
temperature, humidity, cleanliness and distribution
have been controlled
Label the components in the Aircraft Conditioning System
Book 7
- Flow Control Valve
- Pressure Regulating Valve
- Temperature Control Valve
- Secondary Heat Exchanger
- Primary Heat Exchanger
- Air Cycle Machine
- Mixing Chamber
- Water Seperator
- Humidifier
Describe the following components of a Aircraft Conditioning System
* Pressure Regulating Valve
* Flow Control Valve
* Primary/Secondary Heat Exchanger
* Air Cycle Machine (ACM)
* Water Separator
* Humidifier
* Mixing Chamber
Book 7
- Pressure Regulating Valve), in conjunction with a pressure ratio limiting unit, maintains a pressure
ratio - Flow control valve is designed to control the quantity of air flowing through the system and in some
applications, controls the distribution of this air - Heat exchangers reduce the temperature of engine bleed
air - The ACM, also known as Cold Air Unit, is divided into two sections: the
compressor section and the turbine section - Water separators remove excessive moisture from the air
- Humidifier increases the moisture content of the air
- The mixing chamber enables cool turbine air and bleed air
to mix together to obtain the required temperature before
entering the cabin and flight deck.
What is the function of a pressure-relief valve in a water separator?
Book 7
They open at a pre-set value and allow the conditioned air to bypass the water separator, or a valve may
open to direct some warm air to the water separator in the case
of icing.
Duct Pressure-Relief Valve
Book 7
A duct pressure-relief valve ensures that a dangerous pressure build-up is avoided in the ducting if a malfunction occurs in the air supply to the air-cycle, air conditioning system.
A duct pressure-relief valve relieves or dumps excess air pressure overboard.
What is the temperature of the air leaving and air entering the A.C Packs
Book 7
The air entering the air-conditiong packs will be about 200°C and the air leaving the packs will be around 5°C
What is the temperature range that cockpit temp can be alterted to by mixing 200°C hot air with 5°C pack air?
Book 7
By mixing 200°C hot air with 5°C pack air, the cockpit/cabin
environment can be altered anywhere from 18°C to 30°C.
What happens to the air from the cabin and cockpit?
Book 7
A portion of the air is filtered and force fed by fans to the mix manifold to be used again.
What is the fuel source for the aircraft’s combustion process?
Book 7
Aircraft fuel using a dedicated fuel line to the combustor
The combustor is a critical component in the aircraft engine where fuel is mixed with air and ignited.
What starts when the aircraft is on the ground?
Book 7
When the aircraft is on
the ground, a ventilating
air blower starts and
delivers air to the heater.
What does the ventilation air do in the chamber?
Book 7
Dissipates the heat from the chamber
Ventilation air plays a crucial role in maintaining optimal temperatures during operation.
What continues throughout the flight while the system is turned on?
Book 7
The cycling of the combustion process
This indicates an ongoing operational cycle that is critical for flight performance.
What do the following three themal switches do in a combustion heater system?
- Blower Overrun Switch
- Thermal Cycling Switch
- Overheat Switch
Book 7
- ‘Blower overrun switch’ allows the fan to continue to run after heater shutdown. This allows the combustion assembly to cool down.
- ‘Thermal cycling switch’ regulates heat output by intermittently interrupting the fuel supply
- ‘Overheat switch’ will cause fuel interruption in case the thermal cycling switch fails
What are the two systems used in an Equipment Cooling System and what is the difference between them?
Book 7
-
Supply System
The supply fan pushes air to and through the components that have a manifold connected to them. -
Exhaust System
The exhaust fan pulls air from the components that have a manifold connected to them. The check valve
isolates the exhaust air from the downstream area
How many fans can each system in a equipment cooling system have?
Book 7
Both a primary fan and an alternative fan, or just one fan each
This indicates flexibility in fan configuration.
Label the following component and explains its use
Book 7
Low-Flow Sensors
The equipment cooling system
uses low-flow sensors to monitor the cooling quality of airthrough the system.
When a low flow occurs, the low flow sensor supplies an alarm signal to the flight deck for notification
What is the purpose of ducting and vents in the cockpit?
Book 7
To provide the pilot with control of the quantity of air entering the cockpit
This control is essential for maintaining comfort and visibility in varying flight conditions.
