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Aircraft Instrumentation
 

Aircraft Instrumentation

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Please view my latest uploaded presentation. I think I fixed the bugs...

Please view my latest uploaded presentation. I think I fixed the bugs...

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  • nice one Mr smith,it is your great struggle for the aviation industry...........
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  • Nice presentation. Do you have anything for position and warning systems,Hydraulics and landing gear? Thats what I teach we can share presentations. Thank you.
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  • T arrangementMost aircraft built since about 1953 have four of the flight instruments located in a standardized pattern called the T arrangement. The attitude indicator is in the top centerAirspeed to the leftAltimeter to the right and heading indicator under the attitude indicator. The other two, turn-coordinator and vertical-speed, are usually found under the airspeed and altimeter, but are given more latitude in placement. The magnetic compass will be above the instrument panel, often on the windscreen center-post, in this photo it is in the upper right.In newer aircraft with glass cockpit instruments the layout of the displays conform to the basic T arrangement.
  • T arrangementMost aircraft built since about 1953 have four of the flight instruments located in a standardized pattern called the T arrangement. The attitude indicator is in the top centerAirspeed to the leftAltimeter to the right and heading indicator under the attitude indicator. The other two, turn-coordinator and vertical-speed, are usually found under the airspeed and altimeter, but are given more latitude in placement. The magnetic compass will be above the instrument panel, often on the windscreen center-post, in this photo it is in the upper right.In newer aircraft with glass cockpit instruments the layout of the displays conform to the basic T arrangement.
  • Pitot-static errorsThere are several situations that can affect the accuracy of the pitot-static instruments. Some of these involve failures of the pitot-static system itself—which may be classified as "system malfunctions"—while others are the result of faulty instrument placement or other environmental factors—which may be classified as "inherent errors".[6]
  • Blockedpitot tubeA blocked pitot tube is a pitot-static problem that will only affect airspeed indicators.[6] A blocked pitot tube will cause the airspeed indicator to register an increase in airspeed when the aircraft climbs, even though actual airspeed is constant. This is caused by the pressure in the pitot system remaining constant when the atmospheric pressure (and static pressure) are decreasing. In reverse, the airspeed indicator will show a decrease in airspeed when the aircraft descends. The pitot tube is susceptible to becoming clogged by ice, water, inspects or some other obstruction. For this reason, aviation regulatory agencies such as the U.S Federal Aviation Administration (FAA) recommend thatthe pitot tube be checked for obstructions prior to any flight. To prevent icing, many pitot tubes are equipped with a heating element. A heated pitot tube is required in all aircraft certificated for instrument flight except aircraft certificated as Experimental Amateur-Built.[6]Blocked pitot systemThe pitot system can become blocked completely or only partially if the pitot tube drain hole remains open.If the pitot tube becomes blocked and its associated drain hole remains clear, ram air no longer is able to enter the pitot system. Air already in the system will vent through the drain hole, and the remaining pressure will drop to ambient (outside) air pressure. Under these circumstances, the airspeed indicator reading decreases to zero, because the airspeed indicator senses no difference between ram and static air pressure. The airspeed indicator acts as if the airplane were stationary on the ramp. The apparent loss of airspeed is not usually instantaneous. Instead, the airspeed will drop toward zero.
  • Blocked pitot systemThe pitot system can become blocked completely or only partially if the pitot tube drain hole remains open.If the pitot tube becomes blocked and its associated drain hole remains clear, ram air no longer is able to enter the pitot system. Air already in the system will vent through the drain hole, and the remaining pressure will drop to ambient (outside) air pressure. Under these circumstances, the airspeed indicator reading decreases to zero, because the airspeed indicator senses no difference between ram and static air pressure. The airspeed indicator acts as if the airplane were stationary on the ramp. The apparent loss of airspeed is not usually instantaneous. Instead, the airspeed will drop toward zero.
  • If the pitot tube, drain hole, and static system all become blocked in flight, changes in airspeed will not be indicated, due to the trapped pressures. However, if the static system remains clear, the airspeed indicator acts as an altimeter. An apparent increase in the ram air pressure relative to static pressure occurs as altitude increases above the level where the pitot tube and drain hole became blocked. This pressure differential causes the airspeed indicator to show an increase in speed. A decrease in indicated airspeed occurs as the airplane descends below the altitude at which the pitot system became blocked.
  • If the pitot tube, drain hole, and static system all become blocked in flight, changes in airspeed will not be indicated, due to the trapped pressures. However, if the static system remains clear, the airspeed indicator acts as an altimeter. An apparent increase in the ram air pressure relative to static pressure occurs as altitude increases above the level where the pitot tube and drain hole became blocked. This pressure differential causes the airspeed indicator to show an increase in speed. A decrease in indicated airspeed occurs as the airplane descends below the altitude at which the pitot system became blocked.
  • If the pitot tube, drain hole, and static system all become blocked in flight, changes in airspeed will not be indicated, due to the trapped pressures. However, if the static system remains clear, the airspeed indicator acts as an altimeter. An apparent increase in the ram air pressure relative to static pressure occurs as altitude increases above the level where the pitot tube and drain hole became blocked. This pressure differential causes the airspeed indicator to show an increase in speed. A decrease in indicated airspeed occurs as the airplane descends below the altitude at which the pitot system became blocked.
  • If the pitot tube, drain hole, and static system all become blocked in flight, changes in airspeed will not be indicated, due to the trapped pressures. However, if the static system remains clear, the airspeed indicator acts as an altimeter. An apparent increase in the ram air pressure relative to static pressure occurs as altitude increases above the level where the pitot tube and drain hole became blocked. This pressure differential causes the airspeed indicator to show an increase in speed. A decrease in indicated airspeed occurs as the airplane descends below the altitude at which the pitot system became blocked.
  • Blocked static portA blocked static port is a more serious situation because it affects all pitot-static instruments.[6] One of the most common causes of a blocked static port is airframe icing. A blocked static port will cause the altimeter to freeze at a constant value, the altitude at which the static port became blocked. The vertical speed indicator will become frozen at zero and will not change at all, even if vertical airspeed increases or decreases. The airspeed indicator will reverse the error that occurs with a clogged pitot tube and cause the airspeed be read less than it actually is as the aircraft climbs. When the aircraft is descending, the airspeed will be over-reported. In most aircraft with unpressurized cabins, an alternative static source is available and can be toggled from within the cockpit of the airplane.
  • Effect of Nonstandard Pressure and TemperatureIf no means were provided for adjusting altimeters to nonstandard pressure, flight could be hazardous. For example, if a flight is made from a high pressure area to a low pressure area without adjusting the altimeter, the actual altitude of the airplane will be LOWER than the indicated altitude, and when flying from a low pressure area to a high pressure area, the actual altitude of the airplane will be HIGHER than the indicated altitude. Fortunately, this error can be corrected by setting the altimeter properly.Variations in air temperature also affect the altimeter. On a warm day, the expanded air is lighter in weight per unit volume than on a cold day, and consequently the pressure levels are raised. For example, the pressure level where the altimeter indicates 10,000 feet will be HIGHER on a warm day than under standard conditions. On a cold day, the reverse is true, and the 10,000-foot level would be LOWER. The adjustment made by the pilot to compensate for nonstandard pressures does not compensate for nonstandard temperatures. Therefore, if terrain or obstacle clearance is a factor in the selection of a cruising altitude, particularly at higher altitudes, remember to anticipate that COLDER-THAN-STANDARD TEMPERATURE will place the aircraft LOWER than the altimeter indicates. Therefore, a higher altitude should be used to provide adequate terrain clearance.A memory aid in applying the above is “from high to low (or from hot to cold), look out below.”
  • Density altitude is the altitude in the International Standard Atmosphere at which the air density would be equal to the actual air density at the place of observation, or, in other words, the height when measured in terms of the density of the air rather than the distance from the ground. "Density Altitude" is the pressure altitude adjusted for non-standard temperature.Both an increase in temperature and humidity will cause a reduction in air density. Thus, in hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude.

Aircraft Instrumentation Aircraft Instrumentation Presentation Transcript

  • Aircraft Instruments Flight Instrumentation
  • Flight Indicators Pitot-static system  Airspeed Indicator  Vertical Speed Indicator  AltimeterRena H. Smith - Instructor 2
  • Flight Indicators Pitot-static system  Airspeed Indicator  Vertical Speed Indicator  Altimeter Gyroscopic Instruments  Turn coordinator  Artificial horizon  Heading indicatorRena H. Smith - Instructor 3
  • Flight Indicators Pitot-static system  Airspeed Indicator  Vertical Speed Indicator  Altimeter Gyroscopic Instruments  Turn coordinator  Artificial horizon  Heading indicator Magnetic CompassRena H. Smith - Instructor 4
  • Standard “T” Panel & InstrumentsRena H. Smith - Instructor 5
  • Standard “T” Panel & InstrumentsRena H. Smith - Instructor 6
  • Standard “T” Panel & Instruments Airspeed Indicator Attitude Indicator Altimeter (Artificial Horizon) Turn Coordinator Directional Gyro Vertical Speed Indicator (Turn & Bank)Rena H. Smith - Instructor 7
  • Standard “T” Panel & Instruments Pitot Pressure Airspeed Indicator Attitude Indicator Altimeter (Artificial Horizon) Turn Coordinator Directional Gyro Vertical Speed Indicator (Turn & Bank)Rena H. Smith - Instructor 8
  • Standard “T” Panel & Instruments Pitot Pressure Static Pressure Airspeed Indicator Attitude Indicator Altimeter (Artificial Horizon) Turn Coordinator Directional Gyro Vertical Speed Indicator (Turn & Bank)Rena H. Smith - Instructor 9
  • Standard “T” Panel & Instruments Pitot Pressure Static Pressure Airspeed Indicator Attitude Indicator Altimeter (Artificial Horizon) Turn Coordinator Directional Gyro Vertical Speed Indicator (Turn & Bank) Vacuum SystemRena H. Smith - Instructor 10
  • Standard “T” Panel & Instruments Pitot Pressure Static Pressure Airspeed Indicator Attitude Indicator Altimeter (Artificial Horizon) Turn Coordinator Directional Gyro Vertical Speed Indicator (Turn & Bank) Vacuum System Electrical 11Rena H. Smith - Instructor
  • Pitot-Static Instruments Static Pressure Airspeed Indicator Altimeter Vertical Speed Indicator Pitot PressureRena H. Smith - Instructor 12
  • Pitot-Static System  Operates in response to air pressure  Two air pressures: Static pressure • Taken from static vents, powers all three pitot-static system instruments (Altimeter, VSI, ASI) Impact pressure • Powers airspeed indicator onlyRena H. Smith - Instructor 13
  • Pitot-Static SystemRena H. Smith - Instructor 14
  • Aircraft Instruments AIRSPEED INDICATOR
  • Airspeeds and Airspeed Indicator Airspeed Indicator  Displays difference between pitot (impact) pressure and static pressure  It’s a differential pressure gageRena H. Smith - Instructor 16
  • Airspeeds and Airspeed Indicator Airspeed Indicator  Pressures are equal when airplane is parked on ground in calm airRena H. Smith - Instructor 17
  • Airspeeds and Airspeed IndicatorRena H. Smith - Instructor 18
  • Airspeeds  Indicated airspeed (IAS)  Uncorrected reading from the airspeed indicator  Calibrated airspeed (CAS)  Indicated airspeed corrected for installation and instrument errorRena H. Smith - Instructor 19
  • Airspeeds  True airspeed (TAS)  Calibrated airspeed corrected for temperature and pressure variations  Groundspeed (GS)  Actual speed of the airplane over the ground – this is the TAS adjusted for windRena H. Smith - Instructor 20
  • Airspeeds – color coded VSO – stall speed / minimum steady flight in landing configuration (lower limit of white arc) VFE – max. flap-extended speed (upper limit of white arc) VS1 – stall speed in specified configuration (lower limit of green arc)Rena H. Smith - Instructor 21
  • Airspeeds – color coded VNO – max. structural cruising speed (top of green arc, bottom of yellow arc) VNE – never exceed speed (upper limit of yellow arc, marked in red)Rena H. Smith - Instructor 22
  • Airspeeds, others  VLE – max. landing gear-extended speed.  VA – design maneuvering speed (flown in rough air or turbulence to prevent overstressing airframe)  VY – Best rate-of-climb airspeed (creates most altitude in a given period of time)  VX – Best angle-of-climb speed (airspeed resulting in most altitude in a given distance.)Rena H. Smith - Instructor 23
  • SYSTEM MALFUNCTION Blocked Pitot SystemRena H. Smith - Instructor 24
  • Blocked Pitot System Pitot tube blocked but drain open  Will only affect airspeed indicator  Air in system vents through drain  Airspeed drops to zero  No difference in ram and static pressureRena H. Smith - Instructor 25
  • Blocked Pitot SystemRena H. Smith - Instructor 26
  • Blocked Pitot System  Blocked Pitot & Drain  Air trapped in system  Indicator acts like altimeter  Airspeed changes because pressure changes at different altitudesRena H. Smith - Instructor 27
  • Blocked Pitot SystemRena H. Smith - Instructor 28
  • Blocked Pitot SystemRena H. Smith - Instructor 29
  • Blocked Pitot SystemRena H. Smith - Instructor 30
  • STATIC SYSTEMRena H. Smith - Instructor 31
  • Static System & Altimetry  Static system powers altimeter  Altimeter operates as a barometer  Set altimeter on the ground to local settings  Air pressure decreases at a constant rate per foot increased in lower atmosphere (approximately 1000’ per 1” Hg)  Nonstandard temperature and pressure affect altimeterRena H. Smith - Instructor 32
  • ALTIMETERRena H. Smith - Instructor 33
  • Altimeter  As static pressure decreases, indicated altitude increases  Altimeter setting is adjustable in “Kohlsman Window”, a.k.a Altimeter Setting WindowRena H. Smith - Instructor 34
  • AltimeterRena H. Smith - Instructor 35
  • Altimeter Photo Courtesy: Ellis AviationRena H. Smith - Instructor 36
  • Altimeter  Local altimeter setting will cause the instrument to read the approximate field elevation when located on the ground at the airport  Reset altimeter to 29.92 when climbing through 18,000 feet.Rena H. Smith - Instructor 37
  • Altitude Terminology  Indicated Altitude  Altitude read on the altimeter when it is set to the current local altimeter setting  Absolute altitude  Height above the surface  True altitude  True height above Mean Sea Level (MSL)Rena H. Smith - Instructor 38
  • Altitude Terminology  Pressure altitude  Altitude indicated whenever the altimeter setting dial is set to 29.92 (Standard Datum Plane)  Density altitude  Pressure altitude corrected for non-standard temperature and/or pressureRena H. Smith - Instructor 39
  • Altimetry  Standard day  29.92” Hg and +15 deg. C  On a standard day at sea level, pressure altitude, true altitude, indicated altitude, and density altitude are all equal.Rena H. Smith - Instructor 40
  • VERTICAL SPEED INDICATORRena H. Smith - Instructor 41
  • Vertical Speed Indicator (VSI)  Indicates whether the aircraft is climbing, descending or in level flight  The rate of climb or descent is indicated in feet per minute  If properly calibrated, the VSI indicates zero in level flightRena H. Smith - Instructor 42
  • Vertical Speed Indicator (VSI)  Operates only on static pressure, but is a differential pressure instrument  Static air enters both the diaphragm and the area around itRena H. Smith - Instructor 43
  • Vertical Speed Indicator (VSI)  Operates on the principle of a calibrated leak…Rena H. Smith - Instructor 44
  • Vertical Speed Indicator (VSI)  Face of VSI outputs change in pressure over time displayed in feet per minuteRena H. Smith - Instructor 45
  • Vertical Speed Indicator (VSI) An Instantaneous VSI incorporates accelerometers  These help the instrument indicated changes immediatelyRena H. Smith - Instructor 46
  • SYSTEM MALFUNCTION Blocked Static Port/VentRena H. Smith - Instructor 47
  • Blocked Static System Issues Blocked Static Port  Airspeed reads higher than it should above altitude where it became blocked  Airspeed reads lower than it should below altitude where it became blockedRena H. Smith - Instructor 48
  • Blocked Static System Issues Blocked Static Port  Constant Zero indication on VSI  Frozen Altimeter readingRena H. Smith - Instructor 49
  • Blocked Static System IssuesRena H. Smith - Instructor 50
  • NON STANDARD PRESSURE AND TEMPERATURE “from hot to low (or hot to cold) look out below”Rena H. Smith - Instructor 51
  • “High to low…look out below”  When flying from an area of low pressure/low temperature to an area of higher pressure/higher temperature without adjusting the altimeter setting, the altimeter will indicate lower than the true altitude setting…and vice versa.Rena H. Smith - Instructor 52
  • Density vs. True AltitudeRena H. Smith - Instructor 53
  • VACUUM SYSTEMRena H. Smith - Instructor 54
  • Typical Vacuum System  Gyros can run off vacuum, pressure or electrically operated  Most airplanes have at least two sources of power to ensure one source of bank information if one power source failsRena H. Smith - Instructor 55
  • Typical Vacuum System  A typical vacuum system consist of:  an engine-driven vacuum pump  A relief valve  Air filter  Gauge  Necessary tubing and connectionsRena H. Smith - Instructor 56
  • Typical Vacuum SystemRena H. Smith - Instructor 57
  • GYROSCOPIC PRINCIPLES AND INSTRUMENTSRena H. Smith - Instructor 58
  • Gyroscopic Principles  Rigidity in space  Axis of rotation points in a constant direction regardless of the position of its baseRena H. Smith - Instructor 59
  • Gyroscopic Principles  Precession  Tilting or turning of a gyro in response to a deflective forceRena H. Smith - Instructor 60
  • The Attitude Indicator  Relies on rigidity in space  Direction of bank determined by relationship of miniature airplane to the horizon barRena H. Smith - Instructor 61
  • The Attitude IndicatorRena H. Smith - Instructor 62
  • The Attitude Indicator  Relies on rigidity in space  Miniature airplane remains stationary–horizon movesRena H. Smith - Instructor 63
  • Turn Coordinator Relies on controlled precession for their operationRena H. Smith - Instructor 64
  • Turn Coordinator Relies on precession  As an airplane enters a turn, the TC indicates rate of roll. When bank is held constant, TC indicates rate of turnRena H. Smith - Instructor 65
  • Turn Coordinator Relies on precession  Most TCs display an index on the “Standard- rate turn”, wherein the airplane takes 2 minutes to turn 360 degreesRena H. Smith - Instructor 66
  • Turn Coordinator Relies on precession  The “ball” or inclinometer indicates quality of turn (skid/slip status)Rena H. Smith - Instructor 67
  • Heading indicator  “Gyroscopic compass”  Magnetic compasses are difficult to read and suffer from errors; the heading indicator (also known as a directional gyro or DG)  DGs suffer from precession due to bearing friction – the indicator must be realigned with the magnetic compass during straight-and- level, unaccelerated flightRena H. Smith - Instructor 68
  • Magnetic Compass  Compass points to magnetic north  Susceptible to several errorsRena H. Smith - Instructor 69
  • Magnetic CompassRena H. Smith - Instructor 70
  • Compass Errors  Variation  Deviation  Magnetic DipRena H. Smith - Instructor 71
  • Variation Errors Magnetic poles do not coincide with geographic poles Most places on Earth, the compass needle does not point to True North. Angular differences between magnetic north and true north are called variations and are displayed on aeronautical chartsRena H. Smith - Instructor 72
  • Deviation Errors  The metal, electrical systems, and operating engine all create magnetic fields from the aircraft  Aircraft manufacturers install compensatory magnets to prevent most errors. Remaining errors are called deviation  A card in the aircraft will list the deviation at various different compass pointsRena H. Smith - Instructor 73
  • Dip Errors Magnetic dip:  When turning north from an easterly or westerly heading, the compass lags behind the actual aircraft heading. When a turn is initiated while on a northerly heading, the compass first indicates a turn in the opposite direction  When turning south from an easterly or westerly heading, the compass leads the actual headingRena H. Smith - Instructor 74
  • Dip Errors Magnetic dip:  When a turn is initiated on a southerly heading, the compass immediately leads ahead.  Mnemonic: UNOS – undershoot north, overshoot southRena H. Smith - Instructor 75
  • Dip Errors continued…… Accelerating or decelerating while heading either east or west will also cause compass errors When accelerating on an east or west heading, the compass indicates a turn to the north When decelerating on an east or west heading, the compass indicates a turn to the south Mnemonic: ANDS – accelerate north, decelerate south Compass accurate only in S&L, unaccelerated flightRena H. Smith - Instructor 76
  • Questions? Yours & mine… What instruments run off the vacuum system? Where is the artificial horizon located? What must be done to the altimeter to obtain accurate altitude readings? What is Vne and how is it indicated on the airspeed indicator? What factors determine density altitude? Why is density altitude important?Rena H. Smith - Instructor 77
  • Next Week… - Instrument Repair & Replacement - Precautions, Choosing and Avionics Shop and System maintenanceRena H. Smith - Instructor 78