Author: Wg Cdr Rajagopal

Earth’s Magnetism Magnetism Magnetism is the property of certain materials to create a magnetic force Magnetic force attracts or repels similar materials Ferrous metals like steel, nickel or cobalt can be magnetised Non-ferrous metals like aluminium cannot be magnetised Magnetic Field Magnetic field is the space around magnet where magnetic influence is felt Magnetic lines of force is pattern in a magnetic field Varies with shape and strength of magnet Red end is the north seeking end which points to magnetic north Blue end is south seeking end which points…

Angle of Attack Indicator Angle of Attack Angle of attack is the angle between the wing chord line and the direction of air flow Increase in angle of attack provides increased lift until a certain point Beyond a point drag increases abruptly Can cause aircraft to stall Angle of Attack Indicator Angle of Attack indicator, provides visual indication of angle of attack Used in stall warning system Sensors mounted on the side of front fuselage Types of Angle of Attack Sensors Angle of Attack sensors are of two types Slotted…

Air Data Computer Requirement of Air Data Computer Avoid multiple Pitot and Static lines Provide centralized source of static and pitot pressure Convert pressure data in an electric or electronic format Advantage of Air Data Computer Provide pressure data to other equipments Flight data recorder Navigation computer Auto Pilot Equipments dependent on Air Data Computer ADC provides pressure data to Flight Data Recorder Electronic Flight Information System Warning Systems ATC Transponder Inertial Reference System Flight Control Computer Flight Management System Analogue ADC Analogue ADC E-I bar to convert pressure data…

Machmeter Local Speed of Sound Speed of sound is not constant but varies with temperature Sound travels slower in colder air and faster in warm air Speed of sound decreases with increase in altitude Local speed of sound (LSS) at sea level, in ISA (+ 15 deg C) is 661 knots Local speed of sound (LSS) at 30,000 ft, in ISA (-45 deg C) is 589 knots Calculation of Local Speed of Sound Formula for Local speed of sound in knots = 38.95 x Square root of Absolute Temperature In…

Vertical Speed Indicator Principle of Vertical Speed Indicator VSI is also called Rate of climb or descent indicator (RCDI) Indicates rate of climb or descent by rate of change of static pressure Compares the present static pressure to that of 4 – 6 sec earlier Construction of Vertical Speed Indicator Air tight container with a metering unit retains past static pressure Pressure sensing capsule senses the current static pressure Static pressure differential between the capsule and container gives an indication of vertical speed Metering Unit of VSI Metering unit is…

Errors in Altimeter Position and Instrument Errors in Altimeter Position or Pressure error is caused due to location of pitot head Instrument Error is caused due to mechanical imperfections Position and Instrument error are corrected on ground Residual errors are listed on a correction card Manoeuvre and Time lag Errors in Altimeter Manoeuvre Induced Error causes temporary fluctuations in attitude indications Time Lag Error is caused due to sluggish response of capsule to pressure Servo assisted altimeter avoids time lag error Barometric Error Barometric error is caused due to change…