Lesson 16: Aircraft Instrument Systems
Classification Of Instruments Flight Instruments Engine Instruments Auxiliary Instruments
Flight Instruments Those that help visualize the attitude, location and speeds 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.
Pitot-static System Dynamic Air Pressure - Pressure caused by moving air. Ambient Static Air Pressure - Pressure of non-moving air just outside the aircraft.
Pitot-static System
Pitot Head
Pitot Head
Flush Static Port
Airspeed Indicator Differential pressure gauge that measures the difference between dynamic and ambient static air pressure.
Airspeed Indicator Indicated airspeed The speed of an aircraft as shown on the airspeed indicator. True airspeed The speed at which an aircraft is moving relative to the surrounding air. Calibrated airspeed Indicated airspeed of an aircraft, corrected for installation and instrument errors.
Altimeter A barometer that measures the absolute pressure of the air.
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.
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.
Vertical Speed Indicator The rate of climb indicator Serves only as a backup for the altimeter and airspeed indicator as a pitch indicating instrument. Helps the pilot establish a rate of climb or descent.
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 hole remains open, the airspeed reading will drop to zero. If both pitot tube and the drain hole clog, the airspeed indicator will react like an altimeter.
Blockage Of The Pitot-Static System Static port The indicated airspeed increases as the airplane descends and decreases when it climbs. The altimeter: air pressure in the system will not change and neither will your indicated altitude. VSI continually indicates Zero.
Gyroscopic Instruments
Gyroscopic Instruments Turn coordinator Attitude indicator Heading indicator
Gyroscopic Instruments Rigidity In Space – Once a gyroscope is spinning, it tends to remain in a fixed position in space and resist external forces applied to it.
Gyroscopic Instruments Precession – The tilting or turning of a gyro in response to pressure. The reaction to this force occurs in the direction of rotation, approximately 90° ahead of the point where the force was applied.
Sources Of Power Gyroscopes may be operated by electrical power or by a vacuum (suction) system.
Sources Of Power
Attitude Indicator Vacuum powered instrument which senses pitching and rolling movements about the airplanes lateral and longitudinal axes.
Attitude Indicator
Attitude Indicator
Directional Gyro Vacuum powered instrument which senses yaw movement of the airplane about the vertical axis. Horizontal card directional gyro
Directional Gyro Vertical card directional gyro
Rate Gyros Turn And Slip Indicator Turn Coordinator Inclinometer
Rate Gyros
Turn Coordinator
Floating Magnet-type Magnetic Compass
Engine Instruments
Engine Instruments