certification of fighter class aircraft powerplants
TRANSCRIPT
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BY
C.JAGANATHAN
DEPARTMENT OF AERONAUTICAL ENGINEERING
EXCEL ENGINEERING COLLEGE
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Certification is a process by which the power
plant is recognized as Fit To Fly .
Certification process addresses following issues:
Flight within the acceptable mach no & altitude
combinations
Flights within the prescribed sorties
None of the flight duration exceeded prescribed time
limits
None of the flights exceeded any of the laid downacceptable parameters of the engine or aircraft
Permissible failures of the non critical components
of the engine .
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Driver documents for certification are
AIR STAFF REQUIREMENTS (ASR)
Aircraft designer documents, dictate the following
Single / double engine configuration
Typical type of sorties
Thrust requirements at various legs of sorties
Minimum SFC operation in DRY & WET
Unlimited throttle operation (no Embargo)
Life of the engine in TBO, CL, TTL, CYCLIC LIFE etc Weight of the engine not exceeded in ____ Kgs .
PRELIMINARY DESIGN DOCUMENTS OF THE ENGINE
COVERING THE ABOVE ASPECTS
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PRELIMINARY DESIGN REVIEW (PDR) of the
engine
Following documentary evidences to be
realized Technical specification of the engine
Performance documents of the engine
Performance deck to aircraft designer
Pedigree of all components subsystems usedalong with failure rates & boundary conditions
Design recognition vis vis accepted
specification for conformance
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Necessary to prove by test life & safety criticalcomponents
Zero max Zero cycles of 7000 for cold end
Zero max Zero cycles of 3500 for cold end
Boundary conditions while taking testing shouldmatch engine environment
For safety critical components cyclic loads may have
to be 1.5 times than the max cyclic load
Analysis of the component life has to be carried out
using the material property having (-) 3 values
All stress values (LCF & HCF) and creep properties
have to be arrived (-) 3 values
Castings, Forging properties have to be evolved from
specimens extracted out of castings & forgings
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Temp plates are evolved for various proposed
sorties to classify under benign, medium &
critical categories
Critically factors not to exceed 1.35, 1.8 &2.0 for benign, medium & critical categories
respectively
This is arrived by using conventional
proposals namely A+ B/4 + C/40 Before start off the tests, it is necessary to
finalize test procedure, test item,
measurements & failure criteria etc
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Tests have to be identified as safety level &
life tests based on single of multiple engine
configured aircraft Similarly, class A components under single
engine configuration may be downgraded to
class B components for a double engine
configured aircraftWrong identification can lead to unexpected
failure of component during operation
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Disk burst speed test at 122 % and dwelt for
10 seconds at this max rpm
Necessary to maintain boundary conditions as
that of the engine Blade off test (Both TURBINE & COMPRESSOR)
at max rpm and engine allowed to settle at a
lower rpm without much distress
Engine over speed test, wherein the shaft ismade to fail & turbine rotor spool should
lodge into its respective NGV
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ACCELERATED MISSION TEST (AMT) with a
severity factor of not less than 2.0. Ten hours
dedicated for hot air test
Failure definition is mandatory for theengine, subsystems, modules etc.
Single engine aircraft, fuel system test for
switch over from automatics to manual mode
& vice versa Single engine aircraft, oil interruption test
Casing, pipelines for pressure burst test
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ACCELERATED SIMULATED MISSION
ENDURANCE TEST (ASMET)
Engine endurance test
Altitude test with simulated altitudeconditions
Flying test bed
Subsonic platform
Supersonic platform
Performance of engine & its subsystems
Identification of critical speeds
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Ice inspection test
Sand ingestion test
Armament gas ingestion test
Corrosion susceptibility test Vibration test & its response
Gyroscopic load test
Water ingestion testCustomer air bleed contamination test
Blade & disc deflection test
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PRE FLIGHT RATING TEST (PFRT) Partial endurance test
Development endurance test (10000 Hrs)
Model specification of engine
Engine health monitoring proven system
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No major issues during & after first flightclearance, FINAL FLIGHT CLEARANCE (FFC) is
given.
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Thank you