basic-aircraft-instruments-ppl.pptx

8/17/2019 Basic-Aircraft-Instruments-PPL.pptx

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Basic Aircraft

Instrumentation

Shah Sultan


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• To learn the operating principles of the aircraftinstruments.• To study how to interpret the aircraft’sinstruments.

• To learn how to overcome instrument errors.

Lesson Objectives


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Topics

I. Properties of the Atmosphere

II. Pitot-Static Instruments

III. Gyroscopic InstrumentsIV. Magnetic Compass


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Why do we need to study BAI?

1. Proficiency in interpreting aircraftinstruments makes you a safer pilot.

2. Precision in flying.

. Preparation for !asic instrument flightlesson.

". Preparation for your instrument rating #I$%.


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The Atmosphere& a layer of surroun'ing gasses that is retaine' !y the(arth)s gra*ity.

Characteristics of Air

Mass• Pressure• +ensity• ,emperature


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The Atmosphere

• Air is a perfectly 'ry gas.

• ,emperature at sea le*el is 1oC #o/%.• Stan'ar' temperature lapse rate is 2oC per 10 feet altitu'e gain.• Stan'ar' sea le*el pressure is 2.2 in g0 or 11.2 hPa.• Stan'ar' pressure is 1 inch of mercury per 10 feet altitu'e gain.

International Standard Atmosphere (ISA)


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The Atmosphere


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Airspeed Indicator Vertical SpeedIndicator (VSI)

Altimeter

- Also referre' to as 3Pressure Instruments4 !ecause they rely on the'ifferent air pressures acting on the airplane.


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3+ifferent Air Pressures4


Static Pressure Dynamic Pressure

- Pressure e5erte' !y air resisting

the motion of a soli' o!6ect throughit.

- Air pressure e5erte' all aroun'

us0 in e7ual 'irections.


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Static Pressure

Static Port

• A port locate' outsi'e the fuselage that measures static pressure.• 8ocate' in an area 9hich is free of aero'ynamic 'istur!ances.


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Static PressureDynamic Pressure

Pitot Tube

• (longate' tu!e 9ith a hole oriente' into the relati*e 9in'.• Collects air molecules0 9hich translates into amount of 'ynamic

pressure.• Measures total pressure.

• $am air hole• +rain hole


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Pitot-Static System

• ,he com!ination of the pitottu!e0 static port0 alternate

sources0 accessories an' theinstruments connecte' to it.


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Airspeed Indicator

• +isplays the spee' of theairplane as it passes throughthe air.

• Measures the 'ifference!et9een total pressure an'static pressure.

• Connecte' to !oth the pitot tu!ean' static port.

•

,he only instrument 9hich usesthe pitot tu!e.


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Airspeed Indicator

Parts:

1. Pointer:;ee'le

2. ;um!ering• Miles per hour

•


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Airspeed Indicator

Color Codin

1. >hite Arc & 'enotes the flapoperating range

8o9er limit? VS #Stall spee' in 'irty

configuration%

@pper limit? V/( #Ma5imum flap

operating spee'%


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Airspeed Indicator

Color Codin

2. Green Arc & ;ormal operating range

8o9er limit? VS1 #Stall spee' in clean

configuration%

@pper limit? V; #Ma5. structural

cruising spee'%


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Airspeed Indicator

Color Codin

. Bello9 Arc & Caution spee' range

8o9er limit? V; #Ma5. structural

cruising spee'%

@pper limit? V;( #;e*er e5cee'

spee'%

". $e' 8ine & V;( #;e*er e5cee'

spee'%


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Airspeed Indicator

Color Codin

;ot color-co'e' spee's?

VA & +esign maneu*ering spee'. Spee'

at 9hich 9hen full control 'eflectionis ma'e0 the aircraft 9ill not !eo*erstresse'

V8( & Ma5imum lan'ing gear e5ten'e'

spee'. ,his is the ma5imum spee'at 9hich it is safe to fly a retracta!legear aircraft 9ith the lan'ing geare5ten'e'.


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Airspeed Indicator

!rrors

1. Position (rror & Cause' !y aero'ynamic 'istur!ances 9hich changethe angle at 9hich air enters the pitot tu!e.

2. 8ag (rror & Cause' !y internal friction insi'e the instrument.

. lockage of the pitot tu!e & $e'uces the num!er of air moleculesentering the pitot-static system.

". lockage of the static port & 9ill cause the pressure to !e trappe' in

a particular line of the pitot-static system.


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Airspeed Indicator

Types of Airspeed

1. In'icate' airspee' #IAS% & the rea'ing you get 'irectly from theairspee' in'icator.

2. Cali!rate' airspee' #CAS% & in'icate' airspee' correcte' forinstallation an' instrument errors.

. ,rue airspee' #,AS% & Cali!rate' airspee' correcte' for altitu'e an'non-stan'ar' temperature. $epresents the true spee' of your

airplane through the air.". Groun'spee' #GS% & represents the actual spee' of your airplane

o*er the groun'.


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Altimeter

- Senses pressure changes an' 'isplays altitu'e in feet.


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Altimeter


,he altimeter measures staticpressure an' interprets this asaltitu'e.


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Altimeter


Parts of the Altimeter?

1. Aneroi' >afer2. Internal gearing. ;um!ering". un're's han'

. ,housan's han'D. ,en ,housan's han'E. CrosshatchF. in'o9


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Altimeter



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Altimeter


in'o9

• ,ells the altimeter 9hat the staticpressure is at sea le*el # feet%.• An incorrect altimeter setting 9illin'icate an erroneous altitu'e on thealtimeter.

If you change your altimeter setting from2.2 to 2F.20 your altimeter 9illin'icate?

A.% 10 feet higher.% 10 feet lo9er

C.% 1 feet lo9er


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Altimeter


Types of Altitude

1. In'icate' altitu'e & altitu'e rea' 'irectly off the face of thealtimeter.

2. Pressure Altitu'e & altitu'e rea' 'irectly off the face of the altimeter9hen pressure is set to ISA.

. +ensity Altitu'e & pressure altitu'e correcte' for non-stan'ar'

temperature.". ,rue Altitu'e & height of the airplane a!o*e sea le*el.

. A!solute Altitu'e & height of the a!o*e the (arth)s surface o*er9hich it is flying.


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Altimeter!rrors

1. Pressure (rrors

>hen flying from areas of high to lo9 pressure 9ithout a'6usting forthe ne9 pressure on the


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Altimeter(rrors

2. ,emperature (rrors

>hen flying from areas of high temperature to that of lo9temperature0 your true altitu'e is lo9er than 9hat you are rea'ing


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Altimeter

H Co'es

' & Altimeter set to measure altitu'e from sea le*el

'"! & /iel' ele*ation.

'! & Altimeter setting use' 9hen flying a!o*e the transition layer*

Altimeter set to 2.2 in or 11 hPa

1. ,he altimeter looks for P$(SS@$(.

2. Al9ays make sure your altimeter is set to the correct setting

. If no pressure information is a*aila!le on 'eparture0 set altimeter tothe fiel' ele*ation

". If en route0 you may use a pressure setting of a fiel' 9ithin nmof your position


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Vertical Speed Indicator (VSI)

- +isplays ho9 fast you are ascen'ing or 'escen'ing.


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Measures *ertical spee' !ase' on

'ifferential pressures !et9een 2 cham!ersinsi'e the instrument

Parts?1. +iaphragm2. Capsule

. Gearing


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1. ;ee'le2. ;um!ering

• un're's of /eet

!rrors

8ag (rror & D- secon's of 'elay until

the actual rate of clim! or 'escentis sho9n.

+on)t look on the VSI to maintainaltitu'e. 8ook outsi'e or refer to thealtimeter


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Pitot-Static System Problems

1. Pitot !lockage

• Clogge' ram air hole- ASI 9ill in'icate to ero• Clogge' 'rain hole

- ;o effect• oth ram air an' 'rain holes

clogge'

- ASI 9ill act like analtimeter.


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2. Clogge' static port

a. VSI returns to ero!. Altimeter is froenc. Airspee' in'icator?

- Clim!s & increase- +escents & 'ecrease


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A+oidin pitot-static system problems

•


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• (ngage pitot an':or static port heating

systems @se alternate static air ports #ifapplica!le%

• reak the VSI #the least importantinstrument% to let static pressure from insi'ethe aircraft into the system.

• If airspee' in'icator is inaccurate0 orinoperati*e0 maintain a kno9n pitch an'po9er setting that 9ill gi*e a safe airspee'.


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Aeroperu /light ;o. Dcto!er 20 1D


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III. Gyroscopic Instruments

A gyroscope is !asically a rotating 9heel0 mounte' so that its a5is isfree to mo*e in one or more 'irections.

Characteristics

$igi'ity in Space

nce the gyroscope is spinning0 it ten'sto remain in a fi5e' position in spacean' resists e5ternal forces applie' to it.


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A gyroscope is !asically a rotating 9heel0 mounte' so that its a5is isfree to mo*e in one or more 'irections.

Characteristics

Precession

If a force is applie' to the gyroscope0the resultant force 9oul' act o ahea'of the plane of rotation.


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Sources of Po#er

1. (ngine-+ri*en Vacuum System & ,he engine 'ri*es a *acuum pump9hich accelerates air an' rotates the gyros.

- Inaccurate at lo9 po9er settings.

2. Venturi-+ri*en Vacuum System - utsi'e air enters0 is accelerate'through a *enturi an' rotates the gyros. ighly 'epen'ent onairspee'

. (lectrically Po9ere' System & (lectrical po9er turns the gyros.Commonly use' alongsi'e engine-'ri*en *acuum systems topro*i'e re'un'ancy in case of failure


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Sources of Po#er

Suction ,aue

-In'icates the functionality the gyro system.

8o9 Pressure & inaccurate in'ication

Green $ange & normal operation

igh Pressure & 'amage to gyros

Cessna 12 & ;ormal operating range of your suction

gauge is ".D & ." in g.


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eadin Indicator Attitude Indicator Turn Coordinator


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eadin Indicator- >hen properly set0 the ea'ing In'icator is your primary source for

hea'ing information.

Parts of the I1. Aircraft Sym!ol2. Compass $ose. ea'ing ug". "J ,ick Marks

. A'6ustment


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eadin Indicator- >hen properly set0 the ea'ing In'icator is your primary source for

hea'ing information relati*e to the ;orth.

1. +irectional Gyros are ;, north seeking.2. Align the +G)s 9ith the magnetic compass !efore flight.

. +G)s are su!6ect to gyroscopic precession.

". Cross-check an' realign the gyros e*ery 1 minutes 9ith the magneticcompass.

•Accepta!le precession rate is 'egrees e*ery 1 minutes.


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Attitude Indicator- Sho9s the relationship !et9een the 9ings0 an' aircraft nose in

relation to the horion.

Parts of the AI1. Aircraft Sym!ol2. orion. Pitch Scale". anking Scale. ank Angle Pointer

D. Caging


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peration

• Gyro spins horiontally

• Mo*ement of the gim!als is

'isplaye' as a mo*ement of the

horion on the instrument face.


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• Attitu'e In'icator 'oes T indicate direction of fliht0simply0 9here your nose is pointe' an' ho9 your 9ings arepositione'.

• In e5treme attitu'es0 the AI gyro may Ktum!le4 out of a5is0 an'9ill take a certain amount of time to reco*er.

• nce le*el flight has !een esta!lishe'0 align the miniatureairplane 9ith the horion !ar.


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Turn Coordinator- senses rate of turn #ya9%0 roll rate an' coor'ination of the airplane.

,urn an' Slip In'icator


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Turn and Slip Indicator- senses rate of turn #ya9% an' coor'ination only. Commonly use' in

ol' aircraft

Parts

1. ;ee'le

2. ,urn an' 8e*el in'ices

. Inclinometer


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Turn Coordinator- senses rate of turn #ya9%0 roll rate an' coor'ination of the airplane.

Parts

1. Miniature airplane

2. ,urn an' 8e*el in'ices

. Inclinometer

". Gyro

. Gim!als

D. Gearing

G


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Turn Coordinator

,he stan'ar' rate turn is a turn that changes its hea'ing 'egreese*ery secon'. Also kno9n as 3rate 14 turn.

• 1F 'egree turn is ma'e in 1 minute

• D 'egree turn is ma'e in 2 minutes

Slip & rate of turn is too slo9 for the angle of !ank

Ski' & rate of turn is too great for the angle of !ank

III G i I


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Turn Coordinator

• Al9ays ST!P T! .A//&

• Most mo'ern-'ay ,C)s areelectrically po9ere' & Check the

P0 or the instrument face.

• If ,C)s are electrically po9ere'0 afailure 9ill !e in'icate' !y a failureflag.

• ,he inclinometer 'oes not rely onsuction pressure or electrical po9er

• $ate 1 turns are use' in a'*ance'phases of flight training.

III G i I t t


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,yroscopic System perational otes

• Mo*ing the airplane 9hen gyros are not at full $PM can'amage the gyros an' lea' to inaccurate instruments

• After start-up0 >ait until the gyros are fully 3spinne'4 until you

ta5i out the airplane.

• After shut'o9n0 9ait until the gyros are silent an' fully 3spinne'4 'o9n until you mo*e the airplane.

• o9 'o you kno9 if it has spinne' up or 'o9nL 8isten

•/lying 9ith e5cessi*ely high *acuum pressure may 'amage thegyros.

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IV. a!netic "ompass

- it is your primary source of 'irection information.- it is the only 'irection-seeking instrument in your cockpit.

- points to the Magnetic ;orth.

Parts:

1. Pointer

2. Compass

. Magnetic +e*iation Car'

IV ti "


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IV. a!netic "ompass


• Magnetic north is 'ifferent from,rue ;orth

• ,rue ;orth is the geographic

north0 'ra9ing a line 'egreesperpen'icular from the e7uatorto9ar's the ;orth.

• Magnetic ;orth is 9hich thecompass references to.

• ,his 'ifference is calle' themagnetic *ariation.

IV ti "


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IV. a!netic "ompass


Magnetic Variation - the angular 'ifference !et9een true north an'magnetic north at any particular point of the (arth.

Variation to the (ast

If a map in'icates an 3(4 *ariation0

su!tract the *ariation from the ,$@(

(A+I;G.

Variation to the >estIf a map in'icates a 3>4 *ariation0 a''

the *ariation to the ,$@( (A+I;G.

0!ast is /east$ 1est is .est2

IV ti "


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IV. a!netic "ompass


Magnetic +e*iation

• Interference cause' !y metallic o!6ects in the aircraft panel.

• Cause a certain amount of inaccuracy in the magneticcompass.

• A Compass Car' is pro*i'e' to sho9 correction for errors

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IV. a!netic "ompass


Magnetic +ip

-the angle ma'e !y a compass nee'le 9ith the horiontal at anypoint on the (arths surface.

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IV. a!netic "ompass


Acceleration an' +eceleration (rrors

>hen flying on an easterly or 9esterly hea'ing0 acceleration an''eceleration errors are most prominent.

>hen accelerating?

,he compass in'icates a turn to the north

>hen 'ecelerating?

,he compass in'icates a turn to the south

3emember the mnemonic: 0ADS2

IV ti "


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IV. a!netic "ompass


,urning (rrors

• >hen making turns to9ar's the north orsouth0 the compass ten's to lag or lea' ahea'

of actual hea'ing.

;$,

• /rom a ;orth hea'ing0 the compass 9ill initiallyin'icate a turn to the opposite 'irection.

• /rom an (ast or >est hea'ing turning to ahea'ing of north0 there is no error as you !eginthe turn0 !ut the compass increasingly lags!ehin' the airplane)s actual hea'ing as youapproach the north hea'ing.

4n'ershoots

orth

IV ti "


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IV. a!netic "ompass


,urning (rrors

• >hen making turns to9ar's the north orsouth0 the compass ten's to lag or lea' ahea'

of actual hea'ing.

S@,

• /rom a hea'ing of south to9ar's an east or9est hea'ing0 the compass 9ill sho9 theproper 'irection of the turn !ut its rate isactually faster.

• /rom a hea'ing of east or 9est to south0 thecompass 9ill in'icate correctly at the start ofthe turn0 !ut 9ill increasingly lea' theairplane)s actual hea'ing.

4n'ershoots

orth

*ershoots

South

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IV. a!netic "ompass


+etecting /ailures

• u!!les insi'e the Magnetic Compass

• 8i7ui' le*el in the compass is !elo9 stan'ar'

• ,here is a leak in the compass housing

• ,here is no mo*ement on the compass face 9hen turning.

IV ti "


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IV. a!netic "ompass


perational ;otes

• Compass mo*es in the opposite 'irection of the turn.

- If you turn to the right0 it 9ill rotate to the left

- 3/ly a9ay4 from the hea'ing you 9ant to achie*e.

• Al9ays calculate for magnetic *ariation

• Check the compass car' for magnetic 'e*iation

• Compass is only 1N accurate in straight an' le*el0 un-

accelerate' flight.•


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#$ectronic %$i!ht &isp$ay '#%&(

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