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 2-1 Inner and outer platforms
• Arc length
• Axial location of forward and aft face
• Functional fits at interfaces
• Part/assembly locating features (axial, radial and tangential)
• Inner and outer gas path contours
• Air sealing surfaces (axial, radial and tangential)
• Surface finish
• Unbalance: tang loading/dysfunction
• Width: binding, leakage/cavity ingestion Dimensional process control and inspection 2-2 Airfoil external shape
• Aero contour/stagger angle
• Thickness distribution
• Effects on down stream turbine blades
• Poor aero performance
• Airfoil vibratory mode changes due to thickness distribution
• Vane throat area – bearing load, cavity purge, operability, work split, stage loading Surface dimensional process control Assessment of exit flow characteristics 2-3 Airfoil wall thickness Thickness vs. chord and span • Weight
• Airfoil stress/life Dimensional process control 2-4 Airfoil internal cavities
• Passage area and blockage
• Turbulator height and shape
• Internal wall coating
• Small area: large pressure loss, backflow, ingestion, overtemperature
• Large area: insufficient vane cooling Dimensional process control and inspection of passage geometry 2-5 Tolerance • Variance-fluctuations in measurements
• Measurement gauge repeatability and reliability Mechanical/Functional, failure due to vibration from nominal • Verify part is tolerant to variation
• Control of manufacturing and inspection processes 2-6 Cooling baffle • Mass flow
• Standoff
• Low flow: excessive pressure loss, back flow, etc
• High flow: low impingement cooling, excessive part temp, etc
• Low standoff: low impingement cooling, excessive part temp, etc
• Verify part is tolerant to variation
• Control of manufacturing and inspection processes 2-7 Interstage seal • Dimension
• Honeycomb dimensions
• Insufficient interstage sealing: Insufficient upstream cavity purge, etc
• Excessive interstage sealing: Insufficient downstream cavity purge, etc
• Poor cutting characteristics, rubbing, thermal instability, etc
• Verify part is tolerant to variation
• Control of manufacturing and inspection processes 2-8 Airfoil to platform filets
• Filet profile • Failure due to stress concentration. • Dimensional process control.
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
• Poor TBC adherence Material selection Master heat and Process control 3-2 Physical properties • Density
• Coefficient of thermal expansion
• Refractive index (x-rays)
• Excessive vane weight
• Excessive thermal stresses
• Interference with surrounding hardware Verify:
• Acceptable vane weight
• Acceptable stresses
• Vane “fit” in hot condition 3-3 Mechanical /metallurgical properties
• Modulus (vs. grain orientation)
• Columnar crystal orientation angles
• Bare and coated: tensile (UTS, YS, elongation, stress rupture, creep, LCF, HCF)
• Long term metallurgical stability
• Thin wall effects
• Excessive strain-controlled stress
• Undesirable natural frequency
• Low material properties, vane dysfunction
• Material capability consumed in operation Verify:
• Acceptable stresses and frequencies
• Grain orientation, as required
• Adequate material properties
• Operational effects accounted for
• Relevant properties are used 3-4 Cast structure • Grain structure (size, shape, flow, boundaries, gamma prime size and volume fraction, recrystallization)
• Inclusions
• Freckling
• Porosity
• High angle boundaries - directional properties
• Hardness
• Melting point
• Crack propagation rate
• Refractive index Material property reduction due to excessive grain angle or high angle boundaries (HAB), Verify that grain orientation or high angle boundaries are accounted for Process control and inspection 3-5 Environmental resistance
• Oxidation, corrosion, erosion, fretting resistance
• Elevated temperature (creep, diffusion, ageing, temp. gradients)
• FOD resistance Cracking from oxidation/corrosion pitting, vane dysfunction Verify adequate environmental properties 3-6 Environmental coating
• Coverage and thickness
• Long term stability
• Oxidation and corrosion resistance
• LCF property reduction due to poor coating selection/requirements, vane cracking
• Cracking from oxidation/corrosion pitting
• Control of chemistry and application process
• Verify thermal-mechanical compatibility with base material 50
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 3-7 Thermal barrier coating
• Coating material composition and density
• Thermal conductivity (coefficient of thermal expansion)
• Coverage and thickness uniformity
• Coating and diffusion zone microstructure
• Adhesion
• Oxidation
• Resistance to spalling, sintering and erosion
• Hardness
• Residual Stress
• Stripping requirements
• Bonding (interface contamination)
• Compatibility with base material/other coatings High thermal stresses or part temperature, vane dysfunction
• Control of chemistry and application process
• Verify part is tolerant to missing TBC
• No high TBC temperatures that accelerate spalling, or molten dirt infiltration 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 Casting cleanliness • Inclusions and porosity
• Internal surface cleanliness Crack growth from inclusion or porosity Poor coating adhesion, corrosion and oxidation
• Process control (mold setup, casting process, and filtration)
• Process control and sequencing 4-2 Heat treatment • Time @ temperature and ramp rates
• Manufacturing sequence
• Atmosphere Incorrect Gamma prime size/spacing 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 precipitates, gamma prime and volume fraction
• Porosity
• Diffusion zone (brazing)
• Heat affected zone (welding)
• Penetration (welding)
• Excess braze allowance
• Filler metal selection Material property reduction • Correct sequencing of braze or weld cycles in the process
• Process control 4-4 Shot peen • Intensity
• Coverage Incorrect compressive stress, cracking, and vane dysfunction Process control 51
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 4-5 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 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
• Nozzle Area Compressor operability Perform analysis at relevant operating conditions 5-2 Vane cooling • Secondary flow circuit
• Vane cooling flow
• Vane cooling Inadequate part life due to analysis overpredicting the vane cooling 5-3 LCF/TMF life analysis – airfoil and shrouds
• Temperature effects
• Multi-axial 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 5-4 HCF life analysis • Temperature effects
• Vibration and mean stress effects Vane resonant vibration, cracking, dysfunction Use applicable properties and Goodman Diagram 5-5 Creep and rupture life analysis
• Temperature effects
• Material thickness effects Vane rupture cracking, dysfunction Use applicable properties 5-6 Fracture mechanics • Temperature effects
• Threshold stress intensity
• Crack growth rate Crack growth from defect • Use applicable dA/dN curve
• Predict K using expected defect size 5-7 Tolerance to missing TBC
• Part temperature
• Thermal stress High thermal stress or part temperature, vane dysfunction Perform analysis with predicted TBC loss 52
Appendix 2 Section 5 – Analysis Section/Number Characteristic Critical to Part Functionality Key Characteristics Part and System Failure Modes Risk Mitigation and Control 5-8 Variation • Nozzle or engine characteristics Inadequate part life due to vibration Verify part is tolerant to vibration 5-9 Life calculation • Predicted stress and temperature
• Material properties
• Operating during part life Inadequate part life due to analysis underpredicting Verify correct inputs to lifing process Verify correct ‘mission mixing’ used 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
• Creep
• Stress rupture
• Tensile strength
• Cooling effectiveness
• Internal contamination
• Cleaning requirements 6-2 Over-temperature • Microstructure
• Creep
• Hot corrosion
• Tensile strength 53
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) Could be affected Turbine cooling
6. 33.15 Materials Could be affected
7. 33.17 Fire prevention
8. 33.19 Durability Could be affected
9. 33.21 Engine cooling Could be affected
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 54
Appendix 2 Subpart E – Design and Construction;
Turbine Aircraft Engines
15. 33.62 Stress analysis Could be affected Turbine cooling
16. 33.63 Vibration Could be affected Vane vibration
17. 33.65 Surge and stall characteristics Could be affected Turbine effective area-Operating line migration
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 Turbine efficiency/performance
25. 33.74 Continued rotation
26. 33.75 Safety analysis Could be affected Turbine vane release – downstream effects
27. 33.76 Bird ingestion (Operability aspects of ingestion)
28. 33.77 Foreign object ingestion (Operability aspects of ingestion)
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 Vibration
32. 33.85 Calibration tests
33. 33.87 Endurance test Could be affected Vane durability
34. 33.88 Engine over temperature test Could be affected Vane over temperature capability
35. 33.89 Operation test
36. 33.90 Initial maintenance inspection Could be affected Blade in-service inspection limits 55
Appendix 2 Subpart F – Block Tests; Turbine Aircraft Engines
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 56
Appendix 2 Template #6: Turbine Vane Uncooled Inner Shroud, Ring or Platform Vane Airfoil Vane Packets (may be segmented or continuous) Outer Shroud or Ring Nomenclature for Generic Component Features (all features may not be applicable) 57
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 Weight • As-cast surfaces
• Machined surfaces Engine mass and CG Surface dimensional process control 1-2 Structural strength and vibration characteristics
• Vane natural frequencies
• Major load path
• Vane resonant vibration, cracking, dysfunction
• Static structure malfunction
• Resonance avoidance at steady state operation with margin
• Vibratory and steady state stress within Goodman diagram limits 1-3 Creep, LCF, fracture toughness, tensile overload capability
• Vane geometry
• Vane cooling
• Material mechanical/metallurgical/physical properties
• Vane cleaning requirements/effectiveness (internal passages-intergranular attack) Crack growth from LCF or creep – rupture Verify capability exceeds expected utilization 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 Inner and outer shroud or platform
• Arc length
• Axial location of forward and aft face
• Functional fits at interfaces
• Part/assembly locating features (axial, radial and tangential)
• Inner and outer airsealing surfaces (axial, radial and tangential)
• Inner and outer gas path contours
• Sealing surfaces, surface finish Unbalance tang loading/blade dysfunction Dimensional process control and inspection 2-2 Platform • Width Width: binding, leakage/cavity ingestion Dimensional process control 2-3 Airfoil external shape
• Aero contour/stagger angle
• Thickness distribution
• Poor aero performance
• Airfoil vibratory mode changes due to thickness distribution
• Effect on downstream turbine blade vibratory response
• Vane throat area – bearing load, cavity purge, operability, work split, stage loading
• Weight Surface dimensional process control 58
Appendix 2 Section 2 – Part Shape, size, dimensions and other physical measurable parameters, and interconnectivity with an engine integral part/system 2-4 Tolerance • Variance-fluctuations in measurements
• Measurement gauge repeatability and reliability Mechanical/functional, failure due to vibration from nominal • Verify part is tolerant to variation
• Control of manufacturing and inspection processes 2-5 Interstage seal • Dimension
• Honeycomb dimensions
• Insufficient interstage sealing: Insufficient upstream cavity purge, etc.
• Excessive interstage sealing: Insufficient downstream cavity purge, etc.
• Poor cutting characteristics, rubbing, thermal instability, etc
• Verify part is tolerant to variation
• Control of manufacturing and inspection processes 2-6 Airfoil to platform filets
• Filet profile Failure due to stress concentration • Dimensional process control 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
• Poor TBC adherence Material selection Master heat and process control 3-2 Physical properties • Density
• Coefficient of thermal expansion
• Refractive Index (x-rays)
• Excessive Vane Weight
• Excessive thermal stresses
• Interference with surrounding hardware Verify:
• Acceptable vane weight
• Acceptable stresses
• Vane “fit” in hot condition 3-3 Mechanical /metallurgical properties
• Modulus (vs. grain orientation)
• Columnar crystal orientation angles
• Bare and coated: tensile (UTS, YS, elongation, stress rupture, creep, LCF, HCF)
• Long term metallurgical stability
• Excessive strain-controlled stress
• Undesirable natural frequency
• Low material properties, vane dysfunction
• Material capability consumed in operation Verify:
• Acceptable stresses and frequencies
• Grain orientation, as required
• Adequate material properties
• Operational effects accounted for
• Relevant properties are used 3-4 Cast structure • Grain structure (size, shape, flow, boundaries, gamma prime size and volume fraction, recrystallization)
• Inclusions
• Freckling
• Porosity
• High angle boundaries directional properties
• Hardness
• Melting point
• Crack propagation rate
• Refractive index Material property reduction due to excessive grain angle or high angle boundaries (HAB),
• Verify that grain orientation or high angle boundaries are accounted for
• Process control and inspection 59
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 3-5 Environmental resistance
• Oxidation, corrosion, erosion, fretting resistance
• Elevated temperature (creep, diffusion, ageing, temp. gradients)
• FOD resistance Cracking from oxidation/corrosion pitting, vane dysfunction • Verify adequate environmental properties 3-6 Environmental coating
• Coverage and thickness
• Long term stability
• Oxidation and corrosion resistance
• LCF property reduction due to poor coating selection/requirements, vane cracking
• Cracking from oxidation/corrosion pitting
• Control of chemistry and application process
• Verify thermal-mechanical compatibility with base material 3-7 Thermal barrier coating (if used)
• Coating material composition and density
• Thermal conductivity (coefficient of thermal expansion)
• Coverage and thickness uniformity
• Coating and diffusion zone microstructure
• Adhesion
• Oxidation
• Resistance to spalling, sintering and erosion
• Hardness
• Residual stress
• Stripping requirements
• Bonding (interface contamination)
• Compatibility with base material/other coatings High thermal stresses or part temperature, vane dysfunction • Control of chemistry and application process
• Verify part is tolerant to missing TBC
• No high TBC temperatures that accelerate spalling, or molten dirt infiltration 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 Casting cleanliness • Inclusions and porosity
• Internal surface cleanliness Crack growth from inclusion or porosity Poor coating adhesion, corrosion and oxidation
• Process control (mold setup, casting process, and filtration)
• Process control and sequencing 4-2 Heat treatment • Time @ temperature and ramp rates
• Manufacturing sequence
• Atmosphere Incorrect Gamma prime size/spacing leading to low material properties Process control and sequencing 60