Appendix 2 Subpart E – Design and Construction:
Turbine Aircraft Engines
15. 33.62 Stress analysis
16. 33.63 Vibration Could be affected Gear vibration-Design
17. 33.65 Surge and stall characteristics
18. 33.66 Bleed air systems
19. 33.67 Fuel system
20. 33.68 Induction system icing (Operability aspects)
21. 33.69 Ignition system
22. 33.71 Lubrication system
23. 33.72 Hydraulic actuating system
24. 33.73 Power or thrust response Could be affected Gear train response
25. 33.74 Continued rotation Could be affected Continued integrity
26. 33.75 Safety analysis Could be affected Gear release
27. 33.76 Bird ingestion (Operability aspects of ingestion) Could be affected Sudden gear train loading
28. 33.77 Foreign object ingestion (Operability aspects of ingestion) Could be affected Sudden gear train loading
29. 33.78 Rain and hail ingestion
30. 33.79 Fuel burning thrust augmenter Subpart F – Block Tests; Turbine Aircraft Engines
31. 33.83 Vibration test Could be affected Gear vibration
32. 33.85 Calibration tests
33. 33.87 Endurance test Could be affected Gear durability
34. 33.88 Engine over temperature test
35. 33.89 Operation test 97
Appendix 2 Subpart F – Block Tests; Turbine Aircraft Engines
36. 33.90 Initial maintenance inspection Could be affected Gear in-service inspection limits
37. 33.91 Engine component tests
38. 33.92 Rotor locking tests
39. 33.93 Teardown inspection Could be affected Gear wear must be within serviceable limits
40. 33.94 Blade containment and rotor unbalance tests (Weight changes)
41. 33.95 Engine-propeller system tests
42. 33.96 Engine tests in auxiliary power unit (APU) mode
43. 33.97 Thrust reversers
44. 33.99 General conduct of block tests
45. Part 33 - Appendix A – Instructions for Continued Airworthiness Could be affected
46. Part 33 - Appendix B - Certification Standard Atmospheric Concentrations of Rain and Hail 98
Appendix 2 Template #11: Compressor Vane Outer spindle Platform Leading Edge Trailing Edge Airfoil Inner spindle Tip Squealer Tip Airfoil Trailing Edge Bleed feature Leading Edge Rails Nomenclature for Generic Component Features (all features may not be applicable) 99
Appendix 2 Section 1 – Part Functional capability, i.e., the action(s) that the part is designed to perform in the product Section/ Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 1-1 Vibration damping Vane rail to case clearance Vane vibration: Vane or case cracking or wear Control vane attachment to case clearance 1-2 Vibration characteristics (HCF capability)
• Vane natural frequencies
• Vibration stress distribution
• Cycles to failure demonstration
• Vibration test set-up and execution criteria, i.e., establishing parameters for vane holding, loading, excitation modes determination, and excitation sensing techniques Vane resonant vibration, cracking, dysfunction Resonance avoidance at steady state operation with margin Vibratory and steady state stress within Goodman diagram limits 1-3 LCF, fracture toughness, tensile overload capability
• Vane geometry
• Material mechanical/metallurgical/physical properties
• Vane separation from tensile overload
• Crack growth from LCF, HCF, or HCF/LCF interaction
• Loss of tip fatigue strength from rubbing Verify capability exceeds expected utilization 1-4 Squealer tip • Squealer tip geometry • Excessive rub load
• Tip cracking or corner loss Surface dimensional process control Section 2 – Part Shape, size, dimensions and other physical measurable parameters, and interconnectivity with an engine integral part/system Section/ Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 2-1 Rail/T-slot • Shape
• Contour
• Location relative to airfoil
• Tolerance (vane root and case slot dimensional spectrums and blade producibility limitations)
• Unbalance tang loading/blade dysfunction
• Incorrect loading on disk/cracking
• Inability to assemble
• Excessive clearance/movement leading to vibration and wear
• Rotor to stator contact Dimensional process control and inspection 2-2 Platform • Width - tangential
• Length
• Outer gas path contour
• Width: binding, recirculation
• Length: rotor/stator rubs
• Platform resonant vibration, cracking, dysfunction Dimensional process control 2-3 Bleed off-take • Orifice size
• Flow characteristics
• Radial location on airfoil where applicable
• Inadequate cooling leading to turbine blade dysfunction
• Incorrect customer bleed
• Poor operability (TBV) Dimensional process control 100
Appendix 2 Section 2 – Part Shape, size, dimensions and other physical measurable parameters, and interconnectivity with an engine integral part/system Section/ Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 2-4 Airfoil external shape
• Aero contour/stagger angle
• Leading edge contour
• Thickness distribution
• Chord
• Poor aero performance
• Airfoil vibratory mode changes due to thickness distribution
• Operability issues – stall leading to lack of thrust and potential damage to flowpath hardware
• FOD tolerance
• Supply bleed pressure – turbine blade/rotor dysfunction
• Airfoil stress/life Surface dimensional process control 2-5 Airfoil wall thickness Thickness vs chord and span • Airfoil stress/life Dimensional process control 2-6 Airfoil internal cavities
• Passage area and blockage • Inadequate cooling leading to turbine blade dysfunction
• Incorrect customer bleed
• Poor operability (TBV) Dimensional process control and inspection of passage geometry 2-7 Tolerance • Variance-fluctuations in measurements
• Measurement gauge repeatability and reliability Mechanical/Functional, failure due to variation from nominal Verify part is tolerant to variation Control of manufacturing and inspection processes 2-8 Trunnions/spindles • Shape
• Location relative to airfoil
• Alignment of inner/outer trunnions
• Indexing feature location relative to airfoil
• Threaded feature and/or insert
• Inability to assemble
• Excessive clearance/movement leading to vibration and wear
• Excessive drag and bushing wear
• Rotor to stator contact
• Incorrect VSV staging leading to airfoil dysfunction or operability or performance issues Dimensional process control and inspection 2-9 Airfoil to platform filets
• Filet profile • Failure due to stress concentration Dimensional process control 101
Appendix 2 Section 3 – Part Materials and Processes – Properties Section/ Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 3-1 Chemistry • Major elements - % variation
• Impurities
• Poor mechanical or environmental properties Material selection Process control 3-2 Physical properties • Density
• Coefficient of thermal expansion
• Melting Point
• Interference with surrounding hardware Verify:
• Acceptable stresses
• Vane “fit” in hot condition 3-3 Mechanical /metallurgical properties
• Modulus
• Forging grain flow angles
• Bare and coated: tensile (UTS, YS, elongation, stress rupture, creep, LCF, HCF)
• Long term metallurgical stability
• Impact properties
• Undesirable natural frequencies
• Low material properties, vane dysfunction
• Material capability consumed in operation Verify:
• Acceptable stresses & frequencies
• Forging grain flow, as required
• Adequate material properties
• Operational effects accounted for Impact testing 3-4 Forged structure • Grain structure (size, shape, flow, boundaries
• Directional properties
• Hardness
• Forging laps
• Homogeneity of forging work throughout part
• Material property reduction due to abnormal grain structure, Vane dysfunction Verify that grain structure are accounted for Process control & inspection 3-5 Environmental resistance
• Oxidation, corrosion, erosion, fretting resistance
• Elevated temperature stress relaxation, alpha case formation)
• Rubbing, FOD resistance
• Cracking from oxidation/corrosion pitting, vane dysfunction
• Property reduction due to brittle Alpha case, vane dysfunction Verify adequate environmental properties 3-6 Environmental coating
• Coverage and thickness
• Long term stability
• Corrosion resistance
• Cracking from corrosion pitting Control of chemistry and application process Verify thermal-mechanical compatibility with base material 3-7 Ti Fire resistance • Rub rate (clearances, relative motion)
• Environment (température, pressure)
• Material of adjacent hardware 3-8 Rail/T-slot/trunnion wear coating
• Wear resistance and abrasiveness
• Coverage and thickness
• Temperature capability Loss of material leading to dysfunction of vane and/or case Verify acceptable wear couple Control of chemistry and application process Verify adequate temperature capability 3-9 Erosion coating • Erosion resistance
• Compatibility with base material
• Performance and operability degradation
• Vane dysfunction due to material property degradation Verify adequate erosion characteristics and base material compatibility 102
Appendix 2 Section 4 – Part Materials and Processes - Processing Section/ Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 4-1 Raw material processing • Inclusions and porosity
• Microstructural characteristics
• Crack growth from inclusion or porosity
• Inadequate material properties and vane blade dysfunction Process control (melt control, cleanliness) Process control and sequencing 4-2 Heat treatment • Time @ temperature and ramp rates
• Manufacturing sequence
• Atmosphere Incorrect structure leading to low material properties Process control and sequencing 4-3 Welding and brazing Effect on base material properties, based on the following:
• Weld or braze strength
• Microstructure (grain size, shape, flow, braze gap, defects, grain boundary precipitate)
• Porosity
• Diffusion zone (brazing)
• Heat affected zone (welding)
• Penetration (welding)
• Excess braze allowance
• Filler metal selection
• Material property reduction
• Braze or weld failure leading to separation of vane assembly Correct sequencing of braze or weld cycles in the process Process control 4-4 Peening • Intensity
• Coverage Incorrect rail/T-slot/trunnion compressive stress, cracking, vane dysfunction Process control 4-5 Material removal – Non traditional (EDM, ECM, laser, water-jet, etc.)and conventional (machining, milling, broaching, grinding, blending, honing, lapping, stripping, etc.)
Micro cracks or recast:
• Inherent to the process
• Due to abusive machining Fatigue capability degradation, due to:
• Surface finish
• Stress risers
• Chemical attack Cracking initiation from micro-cracks or re-cast Verify part is tolerant to proposed limits Process control 4-6 Non-destructive testing (NDT)
• Acceptance limits
• Sensitivity Cracking from excessive defect size Verify part is tolerant to allowable defects 4-7 Process sequencing and significant process identification and substantiation
• Inspection
• Manufacturing
• Process substantiation and control (RSS,RSA,ESA, etc) Inadequate final part form, or defect “escape”, vane dysfunction Verify adequate control of processes and parameters 4-8 Forging process Forging structure:
• Grain Structure (size, shape, flow, boundaries)
• Directional properties
• Hardness
• Forging laps
• Homogeneity of forging work throughout part Material property reduction due to abnormal grain structure, vane dysfunction Process control and sequencing 103
Appendix 2 Section 5 – Analysis Section/ Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 5-1 Operating conditions • Flow path temperatures, pressures, and velocities Inadequate part life due to analysis under-predicting part temperature, mechanical stress Perform analysis at relevant operating conditions 5-2 LCF life assessment • Temperature effects
• Hold time effects
• Mean stress effects
• Notch effects
• Coating effects
• Mesh size Inadequate part life due to analysis
• Using incorrect properties
• Failing to address the ‘key characteristics’ Use applicable properties Select mesh size to correctly model the geometry 5-3 HCF life analysis • Temperature effects
• Vibration and mean stress effects Vane resonant vibration, cracking, dysfunction Use applicable properties and Goodman diagram 5-4 Fracture mechanics • Temperature effects
• Threshold stress intensity Crack growth from defect Use applicable dA/dN curve Predict K using expected defect size 5-5 Variation • Vane or engine characteristics Inadequate part life due to variation Verify part is tolerant to variation 5-6 Life calculation • Predicted stress and temperature
• Material properties
• Operation during part life Inadequate part life +-due to analysis under-predicting Verify correct inputs to lifing process Section 6 – Testing Section/ Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 6-1 Durability • Fatigue
• Corrosion (hot and cold)
• Erosion
• Tensile strength
• Ballistic capability
• Engine Aeromechanical response
• Microstructure Vane dysfunction Perform adequate component and engine testing 6-2 Operability and performance
• Stall margin
• Acceleration rates
• SFC
• Thrust
• Stall leading to lack of thrust and potential damage to flowpath hardware
• Unacceptable acceleration rate
• Unacceptable range and loading capability Engine testing 104
Appendix 2 Section 7 – Potential Impact on Regulatory Requirements Note: The regulatory requirements identified below, which are inclusive up to Amendment 20 of 14 CFR part 33, are intended as a guide to applicants when determining the applicable regulations to which they must show compliance. Those requirements listed as “Could be affected” highlight the regulations whose compliance findings are typically affected by the component or part that this template is addressing.
This guide is not all-inclusive and the applicant remains responsible for identifying the certification basis of the product on which their PMA part is to be installed.
Applicable 14 CFR Part 33 Regulatory Requirements Comments Subpart – A General
1. 33.4 Instructions for Continued Airworthiness Could be affected ICAs including on-wing inspection requirements and on-wing limits
2. 33.5 Instruction manual for installing and operating the engine
3. 33.7 Engine ratings and operating limitations
4. 33.8 Selection of engine power and thrust ratings Subpart B – Design and Construction;
General
5. 33.14 Start-stop cyclic stress (low cycle fatigue)
6. 33.15 Materials Could be affected
7. 33.17 Fire prevention Could be affected Titanium fire
8. 33.19 Durability Could be affected
9. 33.21 Engine cooling
10. 33.23 Engine mounting attachments and structure
11. 33.25 Accessory attachments
12. 33.27 Turbine, compressor, fan, and turbosupercharger rotors
13. 33.28 Electrical and electronic control systems
14. 33.29 Instrumentation connection 105
Appendix 2 Subpart E – Design and Construction;
Turbine Aircraft Engines
15. 33.62 Stress analysis
16. 33.63 Vibration Could be affected Vane vibration-Design
17. 33.65 Surge and stall characteristics Could be affected Compressor stall line - Operating line migration due to erosion
18. 33.66 Bleed air systems Could be affected Pressure at bleed location
19. 33.67 Fuel system
20. 33.68 Induction system icing (Operability aspects) Could be affected Bleed temperature impacts icing system
21. 33.69 Ignition system
22. 33.71 Lubrication system
23. 33.72 Hydraulic actuating system
24. 33.73 Power or thrust response Could be affected Compressor efficiency/performance
25. 33.74 Continued rotation
26. 33.75 Safety analysis Could be affected Compressor blade release-Case containment
27. 33.76 Bird ingestion (Operability aspects of ingestion) Could be affected Compromised aero – missing airfoil
28. 33.77 Foreign object ingestion (Operability aspects of ingestion) Could be affected Compromised aero – missing airfoil
29. 33.78 Rain and hail ingestion
30. 33.79 Fuel burning thrust augmenter Subpart F – Block Tests; Turbine Aircraft Engines
31. 33.83 Vibration test Could be affected Vane vibration-De monstration test
32. 33.85 Calibration tests
33. 33.87 Endurance test Could be affected Vane durability
34. 33.88 Engine over temperature test
35. 33.89 Operation test 106
Appendix 2 Subpart F – Block Tests; Turbine Aircraft Engines
36. 33.90 Initial maintenance inspection Could be affected Vane in-service inspection limits
37. 33.91 Engine component tests
38. 33.92 Rotor locking tests
39. 33.93 Teardown inspection
40. 33.94 Blade containment and rotor unbalance tests (Weight changes)
41. 33.95 Engine-propeller system tests
42. 33.96 Engine tests in auxiliary power unit (APU) mode
43. 33.97 Thrust reversers
44. 33.99 General conduct of block tests
45. Part 33 - Appendix A – Instructions for Continued Airworthiness Could be affected
46. Part 33 - Appendix B - Certification Standard Atmospheric Concentrations of Rain and Hail 107
Appendix 2 Template #12: Compressor Blade Tip Caps Squealer Tip Airfoil Shrouds Leading EdgeTrailing Edge Platform Dovetail Shank Nomenclature for Generic Component Features (all features may not be applicable) 108