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 4-3 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 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 61
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
• Nozzle area Compressor operability Perform analysis at relevant operating conditions 5-2 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 5-3 HCF life analysis • Temperature effects
• Vibration and mean stress effects Vane resonant vibration, cracking, dysfunction Use applicable properties and Goodman Diagram 5-4 Creep and rupture life analysis
• Temperature effects
• Material thickness effects Vane rupture cracking, dysfunction Use applicable properties 5-5 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 5-6 Tolerance to missing TBC
• Part temperature
• Thermal stress High thermal stress or part temperature, vane dysfunction Perform analysis with predicted TBC loss 5-7 Variation • Nozzle or engine characteristics Inadequate part life due to vibration Verify part is tolerant to vibration 5-8 Life calculation • Predicted stress and temperature
• Material properties
• Operating during part life Inadequate part life due to analysis under-predicting Verify correct inputs to lifing process Verify correct ‘mission mixing’ used 62
Appendix 2 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
• Internal contamination
• Cleaning requirements 6-2 Over-temperature • Microstructure
• Creep
• Hot corrosion
• Tensile strength 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 63
Appendix 2 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
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 Subpart E – Design and Construction:
Turbine Aircraft Engines
15. 33.62 Stress Analysis
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 64
Appendix 2 Subpart E – Design and Construction:
Turbine Aircraft Engines
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
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 65
Appendix 2 Template #7: Shaft – Not Life-limited Active Surface Spline Threaded Feature Balance Areas Material Wall Thickness Run Out Shoulder Feature Nomenclature for Generic Component Features (all features may not be applicable) 66
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-forged surfaces
• Machined surfaces
• Inertia • Surface dimensional process control 1-2 Shaft geometry • Diameters
• Attachment point form
• Surface finish
• Surface hardness
• Correct length
• Heat dissipation
• Vibration response
• Dimensional control
• Machining process control 1-3 Vibration characteristics (HCF capability)
• Shaft natural frequencies
• Vibration stress distribution
• Cycles to failure demonstration
• Shaft resonant vibration, cracking • Resonance avoidance at steady state operation with margin
• Vibratory and steady state stress within Goodman diagram limits 1-4 LCF, fracture toughness, tensile overload capability
• Shaft geometry
• Material mechanical/metallurgical/physical properties
• Shaft separation from overload
• Crack growth from LCF, HCF, or HCF/LCF interaction
• Verify capability exceeds expected duty cycle 1-5 Attachment features • Surface finish
• Press fit
• Retaining thread
• Wear resistance on mating component
• Splines
• Surface fret
• Bearing spinning
• Dimensional checks
• Surface dimensional process control
• Verify acceptable wear couple 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 Shaft features • Shape
• Surface finish
• Internal/external diameter
• Edge break, relief cuts
• Splines
• Threads
• Integral raceways
• Oil holes
• Vibration
• Resonant frequencies
• Scuffing
• Dimensional process control and inspection 2-2 Feature locations • Distance to features from datum • Parts mislocated with in engine • Dimensional process control 67
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 2-3 Wall thickness • Transition areas
• Thickness distribution
• Attaching features
• Dampening features
• Balancing features
• Gear vibratory mode changes due to thickness distribution
• Weight – excessive inertia load
• Stress/life
• Surface dimensional process control 2-4 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 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
• Excessive weight
• Excessive loading on retaining features Verify:
• Acceptable stresses
• Operating conditions 3-3 Mechanical /metallurgical properties
• Modulus
• Forging grain flow angles
• Tensile, UTS, YS, elongation, stress rupture, creep, LCF, HCF
• Endurance limit
• Fracture mechanics
• Plasticity model
• Sudden overload properties
• Surface hardness
• Undesirable natural frequencies
• Low material properties: shaft yield or break
• Spalling during operation Verify:
• Acceptable stresses and 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, vibration, Verify that variations in grain structure are accounted for Process control & inspection 3-5 Environmental resistance
• Oxidation, corrosion, fretting resistance
• Elevated temperature stress relaxation
• Surface coating
• Spalling from oxidation/corrosion pitting
• Property reduction due to extreme oil overtemperature or lack of cooling oil Verify adequate environmental properties 68
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
• Micro structural characteristics
• Crack growth from inclusion or porosity
• Inadequate material properties Process control (melt control, cleanliness Process control and sequencing 4-2 Heat treatment • Time @ temperature and ramp rates
• Manufacturing sequence
• Atmosphere
• Tooling and fixturing
• Incorrect structure leading to low material properties Process control and sequencing 4-3 Welding Effect on base material properties, based on the following:
• Weld strength
• Microstructure: grain size, shape, flow, defects, grain boundary precipitates
• Porosity
• Heat affected zone
• Filler metal selection
• Joint design
• Material property reduction
• Weld failure Correct sequencing of weld process Process control 4-4 Peening • Intensity
• Coverage
• Incorrect compressive stress, cracking Process control 4-5 Surface hardening • Time @ temperature and ramp rates
• Manufacturing sequence
• Atmosphere
• Tooling and fixturing
• Improper case depth
• Hardness improper Process control 4-7 Non-destructive testing (NDT)
• Acceptance limits
• Sensitivity
• Cracking from excessive defect size Verify part is tolerant to allowable defects 4-8 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” Verify adequate control of processes and parameters 4-9 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 Process control and sequencing 4-10 Surface treatments Effect on base material properties, based on the following:
• Carburizing
• Shot peening
• Coating
• Polishing
• Material property reduction due to improper processing Process control and sequencing 69
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 • Torque loads
• Oil temperatures
• Speeds
• Transient loads
• 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
• Overloads
• 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
• Shaft resonant vibration, cracking, whipping
• Critical frequency, bending modes
• Use applicable properties and Goodman Diagram 5-4 Fracture mechanics • Temperature effects
• Threshold stress intensity
• Damage tolerance
• Crack growth from defect • Use applicable dA/dN curve
• Predict K using expected defect size 5-5 Variation • Engine operation 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
• Tensile strength
• Spalling
• Engine vibration response
• Microstructure
• Shaft separation • Perform adequate component and/or engine testing 6-2 Operability and performance
• Vibration signature • Excessive vibration • Engine testing 6-3 Locating features • Build tolerances • Engine manual build sheets • Process control 70
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
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 71
Appendix 2 Subpart E – Design and Construction;
Turbine Aircraft Engines
15. 33.62 Stress analysis Could be affected Shaft stress analysis
16. 33.63 Vibration Could be affected Shaft vibration
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
25. 33.74 Continued rotation Could be affected Continued integrity
26. 33.75 Safety analysis Could be affected Shaft release
27. 33.76 Bird ingestion (Operability aspects of ingestion) Could be affected Sudden shaft loading
28. 33.77 Foreign object ingestion (Operability aspects of ingestion) Could be affected Sudden shaft loading
29. 33.78 Rain and hail ingestion
30. 33.79 Fuel burning thrust augmenter 72