Air Speed Indicator Purpose of Air Speed Indicator Air Speed Indicator is designed to detect dynamic pressure ASI measures dynamic pressure and displays it as air speed Units of measurement are normally Knots or Kilometers per hour Principle of Air Speed Indicator ASI senses Pitot pressure and static pressure Pitot pressure is a combination of dynamic and static Dynamic pressure is obtained by subtracting static pressure Dynamic pressure = Pitot pressure – Static pressure Formula for Dynamic pressure = ½ density x velocity2 Construction of ASI Static pressure is provided…
Category: Flight Instruments
Aircraft are equipped with many instruments which assist pilots in safe and efficient flight operations. In this section, we will learn about the instruments used in modern aircraft.
Pressure Measurement
Pressure Measurement Static Pressure Static pressure is the Atmospheric pressure or Ambient air pressure Due to the weight of air column above the aircraft Reduces with increase in altitude as air column above the aircraft reduce Dynamic Pressure Dynamic pressure is the force exerted when air is brought to rest By a moving body like aircraft Pitot Pressure An aircraft in flight is affected by both static as well as dynamic pressures Combined pressure is called Pitot pressure Pitot pressure is a combination of static and dynamic pressures Sensed by…
Temperature Measurement
Temperature Measurement Outside Air Temperature Measurement Outside Air Temperature (OAT) affects air density which in turn affects Aircraft Performance Engine power Measurement of speed & altitude Temperature measurement is required to avoid icing conditions Flight Safety Hazards of Aircraft Icing Aircraft Icing is quite hazardous to flight safety Loss of lift Increase in weight & drag Freezing and Loss of controls Reduced engine power Engine Flame out Airframe Damage Direct Reading Thermometer Direct reading thermometer is fixed on the wind shield of low-speed aircrafts Measures temperature by unequal expansion of…
Design of Flight Instruments
Flight Instrument Design Introduction to Flight Instruments Cockpit instruments and displays provide aircraft’s vital parameters Parameters could be air speed, altitude, position or attitude Displays range from simple dials to liquid crystal displays (LCD) screens Design of displays is a compromise between measuring range and accuracy A linear scale is preferred in certain instruments like Air Speed Indicator A non-linear scale is preferred in instruments like Vertical Speed Indicator Ergonomics in Cockpit Layout Ergonomics also called human engineering is vital to a well designed layout The layout should be easy…
Flight Instuments – Index
Depending on the vintage and the complexity of the aircraft, and a simple dial can seem very different in appearance and sophistication from a modern cathode ray tube or liquid crystal screen. However, certain problems of range, resolution, accuracy and reliability are general characteristics of all instrumentation systems. We shall discuss the various instrumentation used in aviation under the following headings. Characteristics and General Definitions Pitot and Static Sources Air Temperature Measurement The Airspeed Indicator (ASI) The Pressure Altimeter The Vertical Speed Indicator The Machmeter Air Data Computer Terrestrial Magnetism…