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Aircraft Instrument Systems

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Classification Of Instruments

Flight Instruments

Engine Instruments

Auxiliary Instruments

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Flight Instruments

Those that help visualize the attitude, location andspeeds of the aircraft.

Those which indicate the relationship to the air through which we are flying

Those which relate to our position in space

without considering the air.

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Pitot-static System

Dynamic Air Pressure - Pressure caused by movingair.

Ambient Static Air Pressure - Pressure of non-moving air just outside the aircraft.

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Pitot-static System

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Pitot Head

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Pitot Head

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Flush Static Port

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Airspeed Indicator

Differentialpressuregauge thatmeasures thedifferencebetweendynamic andambient static

air pressure.

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Airspeed Indicator

Indicated airspeed

The speed of an aircraft as shown on the airspeedindicator.

True airspeed

The speed at which an aircraft is moving relative to thesurrounding air.

Calibrated airspeed

Indicated airspeed of an aircraft, corrected for

installation and instrument errors.

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Altimeter

A barometer thatmeasures theabsolute pressure of the air.

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Altimeter

Indicated Altitude The altitude shown by an altimeter set to

current altimeter setting.

Pressure Altitude Height above the standard pressure level of

29.92 in.Hg.

Density Altitude Pressure altitude corrected for nonstandard

temperature variations.

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Altimeter

True Altitude The actual height of an abject above mean sea

level.

Absolute Altitude Actual height above the surface of the earth,

either land or water.

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Vertical Speed Indicator

The rate of climb indicator

Serves only asa backup for thealtimeter andairspeedindicator as apitch indicatinginstrument.

Helps the pilotestablish a rateof climb or descent.

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Blockage Of The Pitot-Static System

Pitot Tube Affects only the airspeed indicator, but a

clogged static system affects all three pitot-static instruments.

If the pitot tube is blocked and its drain holeremains open, the airspeed reading will drop tozero.

If both pitot tube and the drain hole clog, theairspeed indicator will react like an altimeter.

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Blockage Of The Pitot-Static System

Static port The indicated airspeed increases as the

airplane descends and decreases when itclimbs.

The altimeter: air pressure in the system willnot change and neither will your indicatedaltitude.

VSI continually indicates Zero.

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Gyroscopic Instruments

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Gyroscopic Instruments Turn coordinator

Attitude indicator

Heading indicator

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Gyroscopic Instruments Rigidity In Space Once a gyroscope is spinning, it

tends to remain in a fixed position in space andresist external forces applied to it.

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Gyroscopic Instruments Precession The

tilting or turning of agyro in response topressure.

The reaction to thisforce occurs in thedirection of rotation,approximately 90 ahead of the pointwhere the force wasapplied.

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Sources Of Power

Gyroscopes may be operated by electrical power or by a vacuum (suction) system.

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Sources Of Power

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Attitude Indicator

Vacuum powered instrument which senses pitchingand rolling movements about the airplanes lateraland longitudinal axes.

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Attitude Indicator

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Attitude Indicator

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Directional Gyro

Vacuum poweredinstrument whichsenses yawmovement of theairplane about thevertical axis.

Horizontal carddirectional gyro

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Directional Gyro

Verticalcarddirectionalgyro

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Rate Gyros

Turn And Slip Indicator

Turn Coordinator

Inclinometer

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Rate Gyros

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Floating Magnet-type Magnetic Compass

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Engine Instruments

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Engine Instruments