electrical & avionic fundamentals 01a

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Electrical & Avionic Electrical & Avionic Fundamentals 01AFundamentals 01A

City & Guilds 2661 Unit 2 City & Guilds 2661 Unit 2

Certificate in Aeronautical EngineeringCertificate in Aeronautical Engineering

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Electrical & Avionic FundamentalsElectrical & Avionic Fundamentals

Aims/Outcomes:Aims/Outcomes:

Explain in simple terms the purpose and operation of Explain in simple terms the purpose and operation of pitot/static and gyroscopic instruments.pitot/static and gyroscopic instruments.

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Blind Flying Panel:Blind Flying Panel:

Air speed indicatorAir speed indicatorArtificial horizonArtificial horizonRate of climb indicatorRate of climb indicatorAltimeterAltimeterDirectional gyroDirectional gyroTurn and slip indicatorTurn and slip indicator

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Blind Blind Flying Panel:Flying Panel:

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Barometric Instruments:Barometric Instruments:

Three instruments operate from Three instruments operate from

the Pitot-static system.the Pitot-static system.

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Pitot-Static System: Pitot-Static System:

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Airspeed Indicator:Airspeed Indicator:

The airspeed indicator shows the The airspeed indicator shows the indicated airspeedindicated airspeed of the air-plane of the air-plane

in nautical miles per hour, commonly in nautical miles per hour, commonly called called knotsknots..

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Altimeter:Altimeter:

The altimeter is the only instrument which shows how high the airplane is The altimeter is the only instrument which shows how high the airplane is above some level. (ex. sea level)above some level. (ex. sea level)

1.1. Pointer 2. Aneroid cell expandedPointer 2. Aneroid cell expanded3. Aneroid cell contracted3. Aneroid cell contracted

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Rate of Climb Indicator orVertical Speed Indicator:

The vertical speed indicator shows The vertical speed indicator shows whether the airplane is flying at a whether the airplane is flying at a

constant altitude, climbing, or constant altitude, climbing, or descending and if climbing or descending and if climbing or

descending, at what rate.descending, at what rate.

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The next three instruments, the attitude indicator, turn coordinatorThe next three instruments, the attitude indicator, turn coordinator

and heading indicator, are gyroscopic instruments.and heading indicator, are gyroscopic instruments.

Each instrument uses a gyroscope to maintain its orientation relative Each instrument uses a gyroscope to maintain its orientation relative

to one or more of the axes of the airplane.to one or more of the axes of the airplane.

Gyroscopic Instruments:Gyroscopic Instruments:

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Attitude Indicator:Attitude Indicator:

The attitude indicator, as its name implies, indicates the attitude of the The attitude indicator, as its name implies, indicates the attitude of the airplane relative to the earth's surface. airplane relative to the earth's surface.

The instrument displays airplane pitch (whether its nose is up or down) The instrument displays airplane pitch (whether its nose is up or down) and airplane bank (the angle the wing forms with the horizon).and airplane bank (the angle the wing forms with the horizon).

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Turn Coordinator or Turn and Slip indictor:Turn Coordinator or Turn and Slip indictor:

The airplane replica in the middle of the instrument rolls proportionally to the roll rate of the airplane.

When the bank angle is maintained, the replica indicates the rate of turn.

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Directional Gyro or Heading Indicator:Directional Gyro or Heading Indicator:

The heading indicator is used because a magnetic compass only works The heading indicator is used because a magnetic compass only works accurately when the airplane is flying straight and level in un-acceleratedaccurately when the airplane is flying straight and level in un-accelerated

flight. flight.

Any time the airplane is banked, pitched, Any time the airplane is banked, pitched, accelerated, or decelerated, the magnetic accelerated, or decelerated, the magnetic

compass gives a wrong reading. compass gives a wrong reading.

The heading indicator solves this problem The heading indicator solves this problem by using a gyroscope instead of a magnet.by using a gyroscope instead of a magnet.

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Air Data Computer:Air Data Computer:

Air Air DataData

ComputerComputer

InputsInputs

Pitot ProbePitot Probe

Static PortStatic Port

Angle of AttackAngle of Attack

Total Air Total Air TemperatureTemperature

OutputsOutputs

AtititudeAtititudeBarometric correctionBarometric correctionComputed AirspeedComputed Airspeed

True AirspeedTrue AirspeedMachMach

Impact PressureImpact PressureTotal PressureTotal Pressure

Static Air TemperatureStatic Air TemperatureTotal Air TemperatureTotal Air Temperature

Angle of AttackAngle of AttackARINCARINC

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AirspeedAirspeed

AltitudeAltitude

TATTATAutopilotAutopilot

INSINS

ECCECC

FMSFMS

Environmental ControlEnvironmental Control

Air Data Computer Outputs:Air Data Computer Outputs:

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Sources of Electrical Power:

Sources from which the Aircraft Engineer Sources from which the Aircraft Engineer can receive an Electrical Shockcan receive an Electrical Shock

Generator (Engine or APU Driven)Generator (Engine or APU Driven)External power supplyExternal power supply

BatteryBatteryStaticStatic

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Electrical Power Isolation:Electrical Power Isolation:

Circuit BreakersCircuit Breakers

FusesFuses

Non-Isolating SwitchNon-Isolating Switch

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Green AVAIL light on the Electrical Green AVAIL light on the Electrical Power Services Panel indicates Power Services Panel indicates

that the electricity being provided that the electricity being provided is the correct FREQUENCY, PHASE, is the correct FREQUENCY, PHASE,

and VOLTAGE, and that it is safe and VOLTAGE, and that it is safe to use.to use.

CRJ200CRJ200

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Electrostatic Discharge:Electrostatic Discharge:

Electrostatic Discharge (ESD) is the transfer of electrical charge Electrostatic Discharge (ESD) is the transfer of electrical charge between any two objects. between any two objects.

A common example of this is the static shock that a person experiences A common example of this is the static shock that a person experiences after walking across a carpet and then touching a metallic object such after walking across a carpet and then touching a metallic object such

as a file cabinet.as a file cabinet.

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Electrostatic Electrostatic

Discharge:Discharge:

Ensure you are at the same Ensure you are at the same

electrical potential as the electrical potential as the

computer with the use of a computer with the use of a

wrist strap.wrist strap.

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Distance Measuring Equipment (DME):Distance Measuring Equipment (DME):

The DME system is composed of a UHF The DME system is composed of a UHF

transmitter/receiver (interrogator) in the transmitter/receiver (interrogator) in the

aircraft and a UHF receiver/transmitter aircraft and a UHF receiver/transmitter

(transponder) on the ground.(transponder) on the ground.

The ground stations are typically co-located The ground stations are typically co-located

with VOR’swith VOR’s.

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Distance Measuring Equipment (DME):

The DME operates by transmitting to and receiving paired pulses from The DME operates by transmitting to and receiving paired pulses from the ground station. the ground station.

The transmitter in the aircraft sends out very narrow pulses at a frequency The transmitter in the aircraft sends out very narrow pulses at a frequency of about 1,000 MHz. of about 1,000 MHz.

These signals are received at the ground station and trigger a second These signals are received at the ground station and trigger a second transmission on a different frequency. transmission on a different frequency.

These reply pulses are sensed by timing circuits in the aircraft's receiver These reply pulses are sensed by timing circuits in the aircraft's receiver that measure the elapsed time between transmission and reception. that measure the elapsed time between transmission and reception.

Electronic circuits within the radio convert this measurement to electrical Electronic circuits within the radio convert this measurement to electrical signals that operate the distance and ground speed indicators.signals that operate the distance and ground speed indicators.

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The transceiver that sends out the The transceiver that sends out the interrogating signal to the ground interrogating signal to the ground

station contains an internal computer station contains an internal computer to measure the time interval that elapsesto measure the time interval that elapses

until the response.until the response.

The distance to the station is a The distance to the station is a slant rangeslant range, ,

expressed in nautical miles. expressed in nautical miles.

For example, if an aircraft were directly For example, if an aircraft were directly

over the DME station at 6,100 ft AGL, over the DME station at 6,100 ft AGL,

the distance indicator would read one mile.the distance indicator would read one mile.


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UHF Antenna

Ground Transmitter

DME Receiver

DMEInstrument

Distance Measuring Equipment (DME):Distance Measuring Equipment (DME):

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VHF Omni-Range (VOR):VHF Omni-Range (VOR):

This navigational method relies on a system This navigational method relies on a system of ground-based transmitters which emit of ground-based transmitters which emit signals that a VOR receiver can interpret. signals that a VOR receiver can interpret.

The VOR receiver can use the signal emitted The VOR receiver can use the signal emitted by a selected ground station to arrive at an by a selected ground station to arrive at an

azimuth reading from the station. azimuth reading from the station.

This azimuth from the station is called a This azimuth from the station is called a radial of the VOR.radial of the VOR.

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VHF Antenna

Ground Transmitter

VOR Receiver

VOR Instrument

VHF Omni-Range (VOR):VHF Omni-Range (VOR):

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Instrument Landing System (ILS):

Modern airports there is auto-land availability using an Modern airports there is auto-land availability using an

Instrument Landing System.Instrument Landing System.

This uses ground beacons to land the aircraft.This uses ground beacons to land the aircraft.

* A localiser beam is really a combination of two ground signals of two * A localiser beam is really a combination of two ground signals of two

different frequencies aimed pointing away from each other at an angle.*different frequencies aimed pointing away from each other at an angle.*

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When you fly the ILS, you're following two signals: When you fly the ILS, you're following two signals: A localizer for lateral guidance (VHF); A localizer for lateral guidance (VHF);

A glide slope for vertical guidance (UHF).A glide slope for vertical guidance (UHF).


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GroundGroundTransmitterTransmitter

AntennaAntenna

AircraftAircraftReceiverReceiver

ControlControlPanelPanel

InstrumentInstrumentDisplayDisplay

Visual GroundVisual Ground

ILS:

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Global Positioning System (GPS):

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Air Traffic Control (ATC) Transponder:Air Traffic Control (ATC) Transponder:

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Traffic Alert and Collision Avoidance System (TCAS):

The system is three dimensional, The system is three dimensional, it measures closure rate in 3D, it measures closure rate in 3D, so the aircraft need not be at so the aircraft need not be at

the same altitude.the same altitude.

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TCAS interrogates proximate aircraft and receives the altitude, bearing TCAS interrogates proximate aircraft and receives the altitude, bearing

(found with its own directional antenna) (found with its own directional antenna)

and other data from the intruder aircraft via ATC system. and other data from the intruder aircraft via ATC system.

The TCAS computer will analyse the data and determine if the intruder The TCAS computer will analyse the data and determine if the intruder

aircraft poses a threat to your aircraft. aircraft poses a threat to your aircraft.

If there is a potential threat, TCAS will issue If there is a potential threat, TCAS will issue visual and aural warnings which which

will instruct the pilot to avoid the conflict. will instruct the pilot to avoid the conflict.

If there is no threat TCAS will track the intruder aircraft’s position.If there is no threat TCAS will track the intruder aircraft’s position.

TCAS:

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Directional Antenna

TCASComputer

ControlPanel

IVSIor

EFISOur AircraftOur Aircraft

IntruderIntruder

TCAS:ATC

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Weather Radar:Weather Radar:

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Weather Radar:Weather Radar:

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Automatic Direction Finding (ADF):Automatic Direction Finding (ADF):