02 airframes notes (atpl)
TRANSCRIPT
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Ground School Day 1 12/29/2015
Types of load
Static: Steady load of some intensity throughout
Dynamic: Varying intensity and direction for
Cyclic:
StressStress is the internal force per unit area inside a structural part as a resultof tension: ension! Compression! orsion! Shear! "ending
Wing (Main Plane)Stress - Bending#n ground: $ings droop due to fuel! engine and its o%n %eight& 'ppersurface under tension and lo%er surface under compression&(n flight: $ings )end up%ards due to lift forces& 'pper surface no% undercompression and lo%er surface under tension&
o mitigate %ind )ending stress in flight
$ing mounted engines
*uel 'sage: Centre tan+ then %ing tan+s ,in)oard then out)oard! if
applica)le-
.ileron 'p *loat: Crude drag inducing deice
Pressurization Stressoop ,adial- and .ial stress
Stressing a material may cause it to change its shape or to deform&his change or deformation is +no% as S.(3&(t %ill go )ac+ to its original dimension proided the change is %ithin its4lastic imit&
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Station numbers
Attachment methodsieting! $elding! .dhesie )onding! "olting!6inning
Material Properties
4lasticity
.)ility to change its shape reersi)ly %hen su)7ected to certain
loads or forces
6lasticity ,or Ductility-.)ility to deform irreerisi)ly under force or load
Stiffness / igidity.)ility to %ithstand reersi)le deformation under load
Strengthesistance to damage
!imit load
Design limit load8aimum load the airframe or component is designed to eperience in
serice
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Design 'ltimate oadoad %hich the structure must %ithstand %ithout collapse
Safety *actor
D'/D
System "esign Philosophy
Safe ife
he structure is gien a life of hours and/or landings or
pressuriation cycles and must )e remoed from serice %henthe appropriate criteria are met&
he life is )ased on fatiue assessment and aircraft role& he
fatigue life must )e recalculated if a change in aircraft role isproposed&
Can a long haul airplane )e used for short sector flights on a long term)asis; 3o! hae to re assessShort term solution for shortage of aircraft; 6ossi)ly
*ail Safe
6hiliosophy anticipates a possi)le failure %ith minimum
(f one component fails! the ad7acent components ta+e up the
load for a limited period of time! usually until the net sericeinspection&
Damage tolerant
Does not hae specified life
a+es structural %ea+ening into account
oading spread oer larger area
Damage can )e detected during the normal inspection cycles
)efore a failure occurs
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*atigue
he life of an airframe is limited )y fatigue %hich is caused )y
load cycles eperience during ta+eoff! landing and pressuriation&
$ohler ,S/3- Cure leads to fatigue
'se less load! more cycle
he more the applied alternating stress! the lesser the num)er of
cycles )efore it leads to fracture
#oc$pit %indo%s
oughened glass %ith inyl interlayers %ith ru))er sealing
Coc+pit %indo% heating
Conductie film applied to inner surfae of outer glass pane toproide electrical heating for anti
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6assengers %indo%s ,6hoto-
8ade of 6lastics ,6erspe-
6assenger Door 6lug ype ,oc+ing 6ins-
Cargo Door
atch type/inge
Pressure Bul$heads
'npressurised areas: 3ose gear "ay! .ir Conditioning
Compressor! 8ain Gear "ay! ail Cone
ail S+id / ail stri+e might damage and depressurie tail cone
*loor Venting ,"lo% out panels-
Decompression in the cargo )ay leads ca)in pressure difference
and ca)in floor might collapse! leading to actiation of the )lo%out )ungs
Aluminium Alloy
Duralmin
.luminium and Copper Good Strength to $eight ratio
6oor corrosion resistance
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Good thermal and electrical conductiity
6oor %elding capa)ility
&ther metals
Steel
anding gear
itanium
ighter than steel
Strong and high corrosion resistance
Can %ithstand high temperatures
'sed in high temperatures areas li+e engine compartment for fire
protection
8agnesium alloys 4cellent strength to %eight ratio
6oor elastic properties
3ot used in primary structures
#omposites,in the form of laminate or sand%ich a+a honey& educe oerall airplane %eight
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Disadantageous1& a+es time to cure
ypical composite materials2& *i)erglass
>& Car)on fi)er=& .ramide ,?elar-
heir composition:
8atri ,esin or *iller-%hich are )asically )inders
*i)res %hich are reinforcements
Anisotropic8eaning %e can tailor to the direction of the loadStiffness of composites depends on the panel design li+e the composition
of the constituents&
'sotropic.luminium or steel hae the uniform stiffness regardless of the directionof the load&
Sand%ich structure composite
%o thin )ut stiff s+in sheets and a light %eight )ut thic+ core
he core! normally of lo% strength material! proides high )ending
stiffness %ith oerall lo% density due to its thic+ness& (t also sta)ilies thecoering sheets&
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'nsuita)le for a)sor)ing concentrated loads&
uselage #onstruction
hree types:
russ Contruction! normally %ith fa)ric s+in @Diagonal )race and
ongeronA
8onocoue Constuction
o S+in a)sor)s all the load
o Cylindrical shape for maimum stiffness
o *ormers or *rames are for shaping& (t does not support any
load
Semi
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Wing construction #antile*er monoplane
Wing construction - #omponents
1& $ing sparsa& 8ain load )earing mem)ers of the %ing)& 8ain spar B thic+est section of the %ing
2& i)s ,hae holes in them to lighten the %eight->& S+in
a& *ormers that proide the %ing %ith cross sectional shape)& ae holes to reduce %eightc& ransfer some load from s+ins to the spar
=& Stringer
Torsion Bo+ or Bo+ SparSpurs )uilt into a )o shape %ith reinforced s+in forming the upper and
lo%er sides of )o
S$in
8ore suited to a)sor)ing stress under tension than under
compression %here )uc+ling tend to occur
Stringers
ong thin mem)er that runs the length of the %inf under the s+in
.)sor) some of the )ending load
elp stiffen the s+in against )uc+ling
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,mpennage
Consists of ailplane and *in
Similar to %ing construction
Wing mounted engines *s Tail mounted ones ail mounted engines more prone to stall )ecause of the shift in
CG
$ing mounted engines more prone to ya% in case of single sided
engine failure
Probability of ailure #ondition and Se*erity ,(nsert 4.S.
chart-
Duple! riple
ard Time Maintenance (different from Safe !ife. in specific toindi*idual component)
ard ime maintenance is a primary maintenance process under
%hich an item must )e remoed from serice at or )efore aspecified time for inspection or oerhaul
.lso +no%n as ime "et%een #erhaul ,"#-
&n #ondition Maintenance
his is a preentie primary maintenance process %hich reuires
that a component )e periodically inspected or chec+ed against
some appropriate physical standard or limit to determine%hether it can continue in serice&
(f the limit is eceeded! the part has to )e replaced
(t is not a philosophy of fit and forget or fit until failure&
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Pascal/s !a%
6ressure E *orce / .rea
*orce E 6ressure .rea
$or+ Done E *orce Distance
6o%er E $D / ime
E *orce Distance / ime
E 6ressure .rea Distance / ime
E 6ressure Volume / ime
8echanical .dantage
he use of a small force to create a larger force else%here
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ydraulics Applications
"ra+es
*laps
anding Gear ,etracta)le-
*light Controls "y conerting pressure energy into mechanical %or+s ,through
actuators-
$hy is hydraulics )etter than 6neumatics
iuid is imcompressi)le
iuid transmits pressue eually
.ir can )e compressed )y 99&F5 of its oulume
.ir is springy
.is has time lag .ir B lea+s are difficult to detect
.ir B not suita)le for heay loads
3o return line needed in pneumatics ,adantage-
ight %eight and no fire haard ,adantage-
Summary
ydraulics is used to conert pressure energy into mechanicalH
ydraulics luid properties
Good lu)rication
o% iscosity
$ide operating temperature range
3on corrosie
Sta)le
3on toic
igh flash point ,if-
Types if hydraulic fluids 8ineral
Synthetic
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8ineral )ased ,D4* S.3 91
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Acti*e 1 Passi*e ydraulics Systems
.ctie system: 6ump reuired
6assie System: 3o pump
4ample: ight aircraft )ra+ing system
Simple ydraulic System
1& eseroir B Standpipe / Stac+pipe is to preent total lea+! stac+pipeleel
2& 6ump>& *ilter! out contaminants / sediments=& 6ressure regulator5& .ccumulator! store it as gien 6S(K& Chec+ ale / 3on return ale! #ne %ay ale ,3V-F& and pump , for ground sericing or manual sericing of cargo doors-
I& 6ressure gauge ,to preent oer pressure in system-9& elief ale10& Selector ale11& .ctuator ,inear/otary-
Scre%7ac+s B Drien )y hydraulic motors ,otary-
ydraulic System Pressureo% 6ressure Systems: 'p to 2000 psiigh 6ressure Systems: >000 psi or higher
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2eser*oir
6roides storage space for system fliud
6roides a resere to compensate for minor lea+s in the system
.llo%s for ariation in fluid olume due to thermal epansion and
actuator operation
6roides space for returning fluid
6urges system of air ,preents caitation %hich ma+es )ra+es
unresponsie-
8ay )e pressuried or 'npressuried
6ressuried )y air from engine )leed ,typically 100psi-
o o gie positie head pressure to pump (nlet
o 6reents caitation
o 8inimise foaming ,preent slushing-
ypes of ydraulic pumps o% pressure pumps
o S6' G4. type
o V.34
igh pressure pumps
o 6iston ypes
Constant Volume
6ump Volume output is fied
. pressure regulator is reuired to unload the
pump %hen system pressure is reached! andthe accumulator maintains the pressurethereafter
Constant 6ressure ,Varia)le Volume-
6ump olume output is aria)le according to
system reuirements to maintain pressure& Self regulated )y output pressure and piston
acting on the s%ash plate angle
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ilter
ocated 7ust after the pump
*ilter solid particles L 25microns
$hen pressure )uilds up to a certain alue! a *(4 "M6.SS%arning %ill come on to %arn of an impending )ypass
#n some system! a red )utton indicator %ill pop up for engineers
to rectify
Pressure 2egulator
.lso +no%n as .uto Cut
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1& *lo% only in one direction2& 6reents )ac+ flo%>& .rro% indicate on the ale to state its flo% direction
andpump
'sually dou)le acting pump
'sed in emergency on smaller aircraft and for ground operation
and maintenance on larger aircraft
Pressure 2elief 3al*e
Safety deice to protect system from oer
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ydraulic use
'nder normal operation condition! fluid is allo%ed to pass through
the fuse&$hen there is a lea+! there %ill )e a pressure drop )ehind the
piston forcing it to close&
light "ec$ Warning 'ndicators
o% fluid Nuantity
igh emperature
System 6ressure o%
6ump o% 6ressure ight
&pen #entre Selector 3al*e
*itted on older light aircraft! serices connected in series
#nly one serice can )e operated at a time
$hen no serice is selected! the fluid passes though the centre
of the open centre selector
$ith a serice selected and actuation completed! the selector
automatically returns to open position
$hat happens if it did not return to open position; 6ressure relief
ale %ill actuate&
#losed 1 Pressurized System
'nloading ale ,6- maintains pressure at deisng alue Junloads pump )y directing fluid )ac+ to reseroir
#perating pressure manintained in the line leading to selector
ale )y accumulator
Can operate multiple serices simultaneously
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i+ed !anding 5ear
ricycle
ail %heel ,ail dragger-
Ad*antages of a Tricycle configuration
4asier to steer
ess li+ely to nose oer in a cross %ind
"etter for%ard ision particularly during taying
Types of undercarriage Shoc$ absorption
4lastic "ungee
eaf Spring Cantileer
#leo
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(ndication system
$arning system
4mergency lo%ering system
2etractable !anding 5ear 'ndications 'p and loc+ed ,3o light-
(n transit! Disagreement %ith Gear eer position! 'nloc+ed
,steady ights-
Do%n J oc+ed position ,Green steady lights-
!anding 5ear &perating SpeedsVloB 8a speed at %hich gear can )e operatedVleB 8a speed at %hich aircraft can )e flo%n %ith gear etended
6ploc$ oo+ feature
#nce landing gear is hoo+ed and loc+ed! hydraulic pressure is
not needed
"o%nloc$
#er
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.ll these are sensed )y .ir/Ground sensors! also +no%n as Suate
s%itches
5ear "o%n Safety !oc$
#n the ground! leer held in D3 position
o 5ear "o%n Pins
emoe )efore flight
0ose %heel
Tyre Sections
Cro%n < hic+est part& Designed for %ear and tear
Shoulder < 3ot designed for %ear and tear
Side%all < hinnest and %ea+est section& .oid doing tight turns
%ith loc+ed inner main %heel "ead < o fit against the rim of the %heel& 6reent air lea+age
Ply 2ating - (nde of type strength
Speed rating 8a speed on ground in mph
A7uaplaning
ayer of %ater lifting the tyre from the run%ay surface reducing
the )ra+ing effect
#ccurs %hen tread depth is completely filled %ith %ater
#ccurs at 9 times the suare root of the tyre pressure ,psi- E
speed in +nots
1 8pa E 1=5psi
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Greatest stress on the tyre is during the touchdo%n& (t can cause
creeping&
ight turns induce ecessie stress on tyre side%all ,and torue
lin+s-
Tyre
u)e tyre
o 6ro)lem %ith tyre creep! %hich can cause damage to
inflation ale and cause a )lo%out& ,ale shearing-o (nternal friction )et%een the tu)e and the tyre! generating
heat
u)eless tyre
o ighter
Creeping can )e descri)ed as
"isc Bra$e System
usible Plug 1 Thermal plugB elease air in eent of oer& #utflo% Vale 8otor/ .ctuators=& 6ressure Controller
5& 4cessie Differential 6ressure elief ValeK& 3egatie Differential 6ressure elief Vale
"ifferential PressureDifferential pressure is the difference )et%een the ca)in pressure andoutside am)ient pressure
he higher the pressure differential the higher the stress on the fuselagestructure
?eeping the maimum differential pressure to a practical minimum %illreduce this stress
herefore the structural strength of the aircraft %ill determine itsmaimum Differential 6ressure
ypical 8aimum Differential 6ressure of large modern aircraft is a)out 9-:
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Modes of #abin Pressurisation1& (so)aric 8ode ,Constant 6ressure / Ca)in .ltitude-2& 8aimum ,Constant- Differential 6ressure 8ode
WarningsCa)in altitude %arning horn %ill sound %hen ca)in altitude eceeds10!000 ft$hen ca)in altitude reaches 1=!000ft! passenger oygen mas+s %ill drop
Safety 3al*e 1 Pressure 2elief 3al*eo protect aircraft from structural damage from ecessie positiedifferential pressure
Safety ale opens %hen ma pressure is eceeded )y 0&25psi
euirement for 2 ale installation
0egati*e "ifferential pressure$hen am)ient pressureL ca)in pressure*uselage su)7ected to crushing effect.ircraft fuselage not designed to ta+e compressie loadsVale opens %hen outside pressure eceeds ca)in pressure )y 0&5
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(cing Condition eists %hen:
emperature is P10 deg Celsius and )elo% ,otal .ir emp in
flight and #. on ground and ta+eoff-! .3D
Visi)le moisture ,clouds! rain! sno%! sleet! mist and fog- is
present
'ce "etection
SmithOs (ce Detector
osemount (ce Detector ,>5+-! $ith icing! sensitiity %ill
decrease
Areas that are protected against icing
4ngine (nta+e ,and some (nlet 6ro)es-
$ing eadig 4dges ,Slats and *laps-
6ropellers $ater $aste Drain 8asts
6itot u)es ,some Static 6orts-
Coc+pit $indo%s
Stall $arning Vanes
#lassification
.nti
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Methods
8echanical
hermal
iuid
Anti-'cing and "e-'cing Systems
1& 8echanical
De& *luid
6ropellers! $ing! $indscreens
"e-icing boots
(nflata)le ru))er mats
#n %ings and some tail surfaces
(nflated alternatiely and symmetrically
#perated %hen ice thic+ness reaches 1&5cm
Mechanical "e-'cing Boots
1& (nflation .ir Source:
6ressure side of acuum pump
4ngine )leed air
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igh pressure reseroir
2& Deflation source:
Vacuum pump
Venturi of e7ector nole
"e-'cing Boots "isad*antages
(ncrease in drag
igher maintenance cost! possi)le )oot lea+
"e-'cing Boots
1 cycle ta+es >= seconds
ime interal )et%een cycles:
(G: 20K sec
4.VM: 2K S4CS
Thermal (Bleed Air)
Common on large modern aircraft
(ce protection for engines and %ings
.ir ducted from engine compressor
Small 6enaltyH loss of thrust
.erofoil eading 4dges
6itot! %aste %ater ehaust
*ront glass shield
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4ngine inta+e and pod
Thermal (electrical Systems)
6ropellers: 4 of )lade and root! spinner cone
eating mat coers 1/> of )lade length from root
$indscreen heaters
6rotect against interior fogging
8a+e %indscreen more resistnant to )ird stri+es
Speed may )e limited to 250 +nots )elo% 10!000ft if system is
inoperatie
eating elements
for pitot pro)es! some static ports ! angle of attac+ panes ,alpha
pro)es- and temperature pro)es&
*ront %indo%: .nti5deg
luid Systems "e-icing Systerms
*luid de
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5round "e-'cing
2ain protection
$indshield $ipers
ain epellanto 'sed in ery heay rain %hen %ipers alone is not effectie
o .pply to one %indo% at a time
3ot to )e used on dry %indshield
6ermanent rain repelling coating layer on %indshield during
manufacture
#RMG43 SMS48S
Supplemental #ygen
Carried in pressuried aircraft in case of emergencies
Safety 6recautions
Care must )e ta+en %ith the use of oygen systems
1& Control ales must )e opened slo%ly ,friction may cause
com)ustion-
2& Contact %ith grease or oil must )e aoided as it can result in a
chemical reaction leading to a spontaneous fire or eplostion
>& Smo+ing is strictly prohi)ited
light #re% Supplemental &+ygen
Stored in the cargo
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"iluter "emand regulator,*light Dec+-
Supply oygen only on demand
4cept %hen in emergency and test positions
"iluter "emand 2egulator
Pa+ and cabin cre% supplemental o+ygen
Chemical generator or high pressure gaseous ,cylinder tan+s-
type
Continuous
Ca)in air is mied %ith oygen
o (t does not gie protection against smo+e and fumes
6a serice units ,6S's- opened automatically at 1=!000 ft&
Chemical generator type opened electrically )y solenoids
Gaseous type opened pneumatically
#hemical 5enerator Type
8inimum 15min oygen supply
#nce process started! cannot )e stopped
(ndicator changes colour from orange to )lac+ once used
.dantages
ight
(nepensie
3o maintenance
ong shelf ife
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Gaseous ype
Self contained
efilla)le
Can )e regulated and )e turned off
irst aid Therapeutic &+ygen
*irst .id #ygen ,6orta)le )ottles- are meant to proide some pa
%ho may reuire additional oygen after an emergency descent due torespiratory pro)lems
#r
o deal %ith pa %ith medical conditions li+e respiratory disorders
during normal flight
.dditional )ottles M6ST )e carried for pa %ith +no%n medical
conditions
lo% rate
= litre flo% for first aid use B >0 min
2 litre flo% for post decompression %al+ around B K0min
Protecti*e Breathing ,7uipment (PB,)
6"4s must )e aaila)le to all cre% mem)ers
Deice must )e a)le to protect the eyes! nose and mouth for
15minutes
(t can )e a porta)le oygen )ottle %ith a full face mas+ #r a smo+e hood
#r coc+pit oygen mas+ %ith smo+e goggles
#re% portable &+ygen %ith full face smo$e mas$ ("emand
Type)
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PB, Smo$e hood
ire Triangle
> elements are reuired to start and support a fire
*uel #ygen
eat
"etection of smo$e ; ire
"y Visual
Smo+e detectors
#erheat detectors
Smo$e "etectors
"elly Cargo and "aggage Compartments .ionics Compartment
aatory
8ain Dec+ Cargo Compartments ,*reighter and Com)i .ircraft-
Smo$e "etector &ptical
$hen smo+e is present! the light %ill )e refracted and sensed )y thephoto electri cell %hich %ill then produce a oltage to )ring on the smo+e%arning
Smo$e "etector 'onization
he air )et%een the 2 plates is ionied )y the radioactie source
and made electrically conductie
$hen smo+e is present! the conductiity is decreased and this is
sensed )y the control circuit to )ring on the smo+e %arning
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&*erheat "etectors
4ngines
.6'
$heel %ells oilet $aste "in
&*erheat type detection
'nit type detector
o "i
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Center electrode! conductie capillary! *iller material! hermistor
8aterial has a negatie co
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*or .6'! if systems detects a fire on the ground %hen )oth
engines are off! it shuts do%n the .6' automatically anddischarges the etinguishing agent& ,(t assumes there is no onein the flight dec+ and plane is on ground-
ire %arning indication re7uirements
1& .ural
"ell! +laon or repetitie chime
2& Visual
8aster %arning caption
Steady red light for the .6'! the appropriate engine or
compartment>& est circuit to chec+ for continuity of the loops as %ell as the %arning
systems
,ngine ire ,+tinguishing Systems
%o shots must )e proided
%o )ottles per engine or one )ottle per engine %ith proisions
for %ither )ottle to )e discharged into the other engine
,+tinguishing Agents ,ngine and #argo #ompartments
*reon B "8 alon 1>01
Very effectie flame fighting
When pushed (0ormally guarded) .ural %arning is cancelled ,if not already cancelled )y pressing
the 8aster $arning-
Sui) is armed
espectie generator is deactiated
*uel! ydraulics! .ir "leed ales are closed ,isolating the
engine-
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S7uib
(s a small eplosie cartridge ,electrically operated-
'pon detonation! the piston is forced do%n to allo% the
etinguishing agent to )e discharged into the selected engine
Thermal discharge
Discharge due to ecessie pressure %ill result in the am)er
discharge light illuminating
.t the same time! an oer)oard discharge dis+ %ill )e isi)le on
some aircraft type on the outside %hen you do your %al+ around
2'5'" 6,! TA0