1、PRINCIPLES OF INSTRUMENT FLIGHTFlight Instrument SystemsGyroscopic InstrumentsPRINCIPLES OF INSTRUMENT FLIGHRequired Instruments for IFR FlightAll required for VFR Flight - plus:Required Instruments for IFR F“GRABCARDD” 91.205 (d) & (e) G enerator or alternatorR adios: Two-way Communication AND navi

2、gation equipment appropriate to facilities usedA ltimeter (adjustable)B all (slip & skid indicator)C lockA ttitude IndicatorR ate of turn indicatorD irectional gyroDME at & above FL 240“GRABCARDD” 91.205 (d) & (e)G Equipment tests & inspections required for IFRAirworthiness Directives (recurring/one

3、-time)VOR (preceding 30 days)Inspections (Annual/100 hour if for hire)Altimeter (preceding 24 calendar monthsTransponder (preceding 24 calendar months)ELT (preceding 12 calendar months)Static system (preceding 24 calendar mo.)Equipment tests & inspections Gyroscopic Flight InstrumentsAttitude Indica

4、tor - Heading Indicator - Turn CoordinatorGyroscopic Flight InstrumentsAFlight Instrument SystemsVacuum SystemAttitude Indicator & Heading IndicatorElectrical SystemTurn CoordinatorServes as backup in case of vacuum system failureFlight Instrument SystemsVacuuVacuum SystemVACUUM SYSTEMVacuum SystemV

5、ACUUM SYSTEMGyroscopic PrinciplesRigidity in SpacePrecessionGyroscopic PrinciplesRigidity Rigidity in SpaceA wheel spinning rapidly tends to remain fixed in the plane in which it is spinning.Gimbals allows the gyro to rotate freely in any planeGives us a center of reference that doesnt change with a

6、ircraft attitudeRigidity in SpaceA wheel spinnGyro stays fixed as aircraft moves around itGyro stays fixed as aircraft mPrecessionApply a force on a spinning gyro, its effect will be felt at the 90 degree position in the plane of rotation.Caused by friction:-in gimbals-in bearingsResults in:-1) slow

7、 drifting in HI and -2) occasional small errors in AIPrecessionApply a force on a sAttitude IndicatorShows aircraft pitch and bank attitudeDoes NOT show if the aircraft is turning, climbing or descendingAttitude IndicatorShows aircra儀表等級飛行員理論培訓stage1-103GYROS-COMPASS課件ATTITUDE INDICATORATTITUDE INDI

8、CATORHow an AI WorksPrinciple of operation: -RIGIDITY IN SPACEGyro spins in horizontal plane on a vertical axisMounted on dual gimbals so that aircraft can pitch and roll around gyroGyro stays level with natural horizon there is a self-erecting mechanism actuated by the force of gravity on “pendulou

9、s vanes” to keep it level*(see next slide)How an AI WorksPrinciple of opThe self-erecting mechanism in the gyroscopic attitude indicatorThe force of gravity acting on the “pendulous vanes” allows the gyro to align itself with the natural horizonThe self-erecting mechanism inPendulous VanesSole purpo

10、se is to keep the gyro ERECT.Air exits the gyro assembly through 4 ports at right angles near the base.Vanes open and close these ports by the swinging effect like a pendulum responding to gravity.Results in differential thrust causing precession forces which right the gyro to desired planePendulous

11、 VanesSole purpose isTurns and G forcesThe pendulous vanes operate asymmetrically under:LoadCentrifugal forceResults in a variety of typical gyroscopic precession errorsError usually maxes out after 180 turn - cancels after 360 turnTurns and G forcesThe pendulou儀表等級飛行員理論培訓stage1-103GYROS-COMPASS課件Ac

12、celeration / Deceleration ErrorsExample - accelerateHorizon bar moves downIncorrectly indicates a climbConfirmed by pilots somatogravic illusionResponse (“get the nose down”)Danger potential at takeoff or missed approach when required obstacle climb angle isnt sufficientAcceleration / Deceleration E

13、rTumbling GyrosOlder AI indicators can tumble.Gimbals reach their limits resulting in gyros precessing rapidly.Tumbles away from desired plane of rotation Exceeding 100 bank or 60 pitch (on older models)Caging devices were necessary for acrobatic flight to prevent tumblingNewer Attitude Indicators d

14、o not have the same limits so no cagingTumbling GyrosOlder AI indicatHeading IndicatorIndicates heading based on a 360 degree azimuthMust regularly be reset to agree with the magnetic compassHeading IndicatorIndicates heaHow An HI WorksVacuum poweredGyro spins on vertical planeSenses rotation about

15、the vertical axisFree vs. Slaved gyrosfree, must align with magnetic compassslaved, automatic north-seekingHow An HI WorksVacuum poweredHeading IndicatorHeading IndicatorHI ErrorsPrecession: Check HI every 15 minutes with mag compassAirplane does more than yaw, so 2 gimbals needed for free rotation.

16、Can also tumbleHI ErrorsPrecession: Check HITURN COORDINATOROperates on principle of gyroscopic precession-Electrically DrivenStill usable after a vacuum failure -Provides direction of turn, rate of turn, rate of roll, and QUALITY of turn (coordinated use of aileron and rudder) TURN COORDINATOROpera

17、tes on prTwo TypesTurn-and-Slip IndicatorOnly shows rate of turnGyro rotates in vertical plane along a/c longitudinal axisTurn CoordinatorIndicates rate of turn AND rate of roll- Gyro is canted 30 degrees to allow for measuring the roll and yaw of the airplaneBoth instruments give indirect indicatio

18、n of bankTwo TypesTurn-and-Slip IndicatSlip and SkidSliprate of turn is too slow for AOBball inside turn -(HCL is too great)Skidrate of turn is too great for AOBball outside turn-(too much Centrifugal force)Slip and SkidSlip Slip Skid Coordinated Slip SRTStandard rate turn is 3/secAngle Of Bank incr

19、eases with TASStandard Rate AOB rule of thumb: (TAS/10) + 1/2SRTStandard rate turn is 3/seTC ChecksListen for unusual noise before starting engine Look for red, warning, or OFF flagsAmmeter after start for positive charging rateInclinometer ball - outside of turnTurn needle - with turnTC ChecksListe

20、n for unusual noMagnetic CompassSelf containedDirection seekingSubject to many Compass ErrorsMagnetic CompassSubject to manMagnetic Compass ErrorsVariationDeviationMagnetic DipOscillationNortherly Turning ErrorAccelerationThese are both due to Magnetic DipMagnetic Compass ErrorsVariatiMagnetic Varia

21、tionDifference between True North & Magnetic NorthIsogonic lines: equal variation Agonic line: 0 variationMagnetic VariationDeviationMetals and magnetic fields in the airplane interfere with north-seeking abilityCompensating magnets eliminate some of the error.Swinging the compass adjusts them.Lefto

22、ver error is handled through a compass correction card for each individual airplane.DeviationMetals and magnetic fMagnetic DipExists because compass magnet tries to point 3 dimensionally toward the earths magnetic north pole deep inside the earth.“Northerly Turning” and “Acceleration” errors are due to magnetic dipMagnetic DipExists because comWhen rolling out to North or South Heading.