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Flight Instrument Systems

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Presentation on theme: "Flight Instrument Systems"— Presentation transcript:

1 Flight Instrument Systems

2 Gyroscopic Flight Instruments
Attitude Indicator Heading Indicator Turn Coordinator Gyros are mounted on gimbals which allow the plane to move about the gyro which remains fixed in space


4 Fundamental Concepts Rigidity in Space - a wheel with a heavily weighted rim spun rapidly tends to remain fixed in the plane in which it is spinning Precession - when an outside force is applied the gyro responds as if the force had been applied at a point 900 further around in the direction of rotation

5 Pendulous Vanes Open and close to help keep the gyro parallel to the ground Act on the attitude indicator in an undesirable way during turns do to centrifugal force Errors are at a maximum in a 1800 turn, no more than 50 of bank

6 Tumbling Old attitude indicators would precess rapidly or tumble if you exceeded 1000 or 600 of pitch Often these attitude indicators had a caging device to right them

7 Heading Indicators Must be aligned with the magnetic compass to make it work (Free Gyro) Must be checked approximately every 15 minutes A heading indicator with a north seeking system is called a slaved gyro.

8 Turn Indicators Standard rate turn is 30 A 3600 turn takes 2 minutes
To determine the angle of bank required to make a standard rate turn take the (true airspeed in Knots divided by 10) + 5 At 100 Knots it is approximately 150

9 Turn Instruments Turn coordinator Turn and slip indicator Inclinometer
Rate of roll Rate of turn Turn and slip indicator Rate of turn only Inclinometer



12 Slip and Skid Slip - rate of turn is too slow for the bank and the ball moves to the inside of the turn Skid - rate of turn is too great for the angle of bank and the ball moves to the outside of the turn

13 Slip

14 Skid

15 Instrument Checks With the power off, warning flags display OFF indications Inclinometer full of fluid and ball at lowest point Turn on master and listen for grinding noise in electric gyros After starting check ammeter

16 Instrument Checks Listen for noise from vacuum gyros
If you think you hear noise, shut off the engine and listen to the gyros spin down It can take 5 minutes for the gyros to reach full operating speed

17 Instrument Checks While taxing out, the turn coordinator and heading indicator should indicate a turn in the correct direction The ball should swing to the outside in turns Align the heading indicator with the magnetic compass during runup and check again before takeoff

18 Magnetic Compass Errors
Variation - the angular difference between the true and magnetic pole Deviation - errors due to magnetic interference with the metal components of the aircraft Magnetic dip - the compass tries to point down deep inside the earth

19 Variation

20 Deviation

21 Magnetic Dip

22 Northerly Turning Error

23 Acceleration Error

24 Pitot Static Instruments
Airspeed Indicator Vertical Speed Indicator Altimeter

25 Airspeed Indicator

26 Airspeed Indicator VSO VNE VNO VFE

27 Colored Arcs Yellow - operate in the caution area only in smooth air
Green - normal operating range White - full flap operating range

28 Types of Airspeeds Indicated - displays the speed of your plane. It is the basis for determining your aircraft performance Calibrated is indicated corrected for installation and instrument error Equivalent airspeed is calibrated airspeed corrected for adiabatic compressible flow at a particular altitude

29 Types of Airspeeds True Airspeed is the actual speed your airplane moves through the air. The calibrated airspeed corrected for density altitude Mach is the ratio of the aircraft’s true speed to the speed of sound

30 Altimeter

31 Types of Altitude Indicated - is what you read on the altimeter
Pressure - is displayed when you have the altimeter set to It is the vertical distance above the standard datum plane Density - pressure corrected for nonstandard temperature

32 Types of Altitude True - is the actual height of an object above mean sea level. Absolute - is the actual height of the aircraft above the earth’s surface

33 ISA International Standard Atmospheric Sea Level - 150 C - 29.92 in HG
Before IFR flight the altimeter set to the current altimeter setting should be within 75 feet of the actual elevation

34 Vertical Speed Indicator

35 Vertical Speed Indicator
Displays rate and trend information 6-9 second delay Gives erratic readings during turbulence or when applying abrupt control inputs Not setting before starting engines and use that setting for zero Not legally required for IFR flight

36 Pitot Static System Ram air inlet Drain hole

37 System Errors Can be caused by blockage of the pitot tube, static port or both Blockages can be caused by moisture, ice, dirt or even insects Use pitot tube cover when parked Use pitot heat when flying in visible moisture

38 Pitot Blockage Ram air inlet clogged, drain hole open pressure in line to airspeed indicator drops to zero, airspeed indicator indicates 0 Ram air inlet clogged, drain hole clogged, air trapped in line, airspeed indicator does not react to changes in speed but altitude like an altimeter

39 Static Blockage Airspeed indicator will continue to react to changes in airspeed but they will not be accurate Altimeter will freeze in place VSI will freeze at zero Use alternate static source or break glass in VSI

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