Appendix 2 145
CATEGORIES OF REPAIR Req No Repair Properties & Requirement to be Identified and Substantiated.
8. Select all that may be potentially affected by the repair design and evaluate system effect(s):
a. Structural Strength, including major load paths
b. Heat Transfer
c. Secondary Airflow
d. Aerodynamics
e. Weight
f. Center of Gravity
g. Moment of Weight
Critical Measurable Characteristics
9. Establish Measurable Characteristics and the allowable tolerances for the repaired part features and for any replacement detail(s) and give due consideration to mating part(s):
a. Surface finish/texture
b. Shotpeen Intensity/Coverage
c. Bearing bore dimensions and location characteristics
d. Pressure Strength Test
e. Flow Capacity test
f. Dimensions, including heat distortion effects Roundness Flatness Parallelism Concentricity True Position Tolerances Edge Distance Requirements Finish Dimensions Requirements
10. Parent material thickness reduction assessment
11. Dimensional & Tolerance Reverse engineered parts
Repair Process Capability Technical Substantiation Requirements
12. Verification Plan with Significant Operations Identified for Repair Source Qualification
Appendix 2 146
CATEGORIES OF REPAIR Req No Repair Properties & Requirement to be Identified and Substantiated.
13. Process Demonstration:
Including variability requirements
14. Part Demonstration/Inspection
15. Manufacturing requirements for fabrication of repair details or replacement sections used to accomplish repair:
Drawings/Specifications Quality Requirements Source Substantiation Requirements
Applicable 14 CFR Part 33 Requirements
Subpart A – General
16. 33.4 Instructions for Continuous Airworthiness (ICA's)
17. 33.5 Instruction manual for installing and operating the engine
18. 33.7 Engine ratings and operating limitations
19. 33.8 Selection of engine power and thrust ratings
Subpart B – Design and Construction; General
20. 33.14 Start-stop cyclic stress (low cycle fatigue) (weight and CG location changes effects on disks)
21. 33.15 Materials
22. 33.17 Fire prevention
23. 33.19 Durability (Note that 33.19 is associated with 33.27; 33.63; 33.83;
33.87; 33.88; and 33.90)
24. 33.21 Engine cooling
25. 33.23 Engine mounting attachments and structure
26. 33.25 Accessory attachments
27. 33.27 Turbine, compressor, fan, and turbo supercharger rotors
Appendix 2 147
CATEGORIES OF REPAIR Req No Repair Properties & Requirement to be Identified and Substantiated.
6 Subpart B – Design and Construction;
General; continued
28. 33.28 Electrical and electronic control systems
29. 33.29 Instrument Control Subpart E – Design and Construction;
Turbine Aircraft Engines
30. 33.62 Stress analysis
31. 33.63 Vibration
32. 33.65 Surge and stall characteristics (Note 2)
33. 33.66 Bleed air system
34. 33.67 Fuel system
Appendix 2 148
CATEGORIES OF REPAIR Req No Repair Properties and Requirements to be Identified and Substantiated.
6 Subpart E – Design and Construction;
Turbine Aircraft Engines
35. 33.68 Induction system icing
36. 33.69 Ignitions system
37. 33.71 Lubrication system
38. 33.72 Hydraulic actuating systems
39. 33.73 Power or thrust response
40. 33.74 Continued rotation
41. 33.75 Safety analysis
42. 33.76 Bird ingestion (operability aspects of ingestion)
43. 33.77 Foreign object ingestion—ice (operability aspects of ingestion)
44. 33.78 Rain and hail ingestion
45. 33.79 Fuel burning thrust augmentor Subpart F – Block Tests; Turbine Aircraft Engines
46. 33.83 Vibration test
47. 33.85 Calibration tests
48. 33.87 Endurance test(see Note 2)
49. 33.88 Engine overtemperature test 50 33.89 Operation test (operability aspects)
51. 33.90 Initial maintenance inspection
52. 33.91 Engine component tests (HCF/LCF bench testing)
53. 33.92 Rotor locking tests
54. 33.93 Teardown inspection
55. 33.94 Blade containment and rotor unbalance tests (weight changes)
56. 33.95 Engine-propeller system tests
57. 33.96 Engine tests in auxiliary power unit (APU) mode
58. 33.97 Thrust reversers
59. 33.99 General conduct of block tests Part 33 —Appendix A – Instructions for Continued Airworthiness DER Part 33— Appendix B- Certification Standard Atmospheric Concentrations of Rain and Hail
Part 34 – Exhaust Emissions
Appendix 2 149 Template 15
REPAIR SUBSTANTIATION CHECKLIST – LOW PRESSURE COMPRESSOR (LPC) – HIGH PRESSURE COMPRESSOR (HPC) STATOR PART FAMILY – VARIABLE
VANE TYPE STATORS
Categories of LPC-HPC Stator Repair. Determine which repair description best fits the repair proposal based. If no repair description is appropriate, contact the FAA Advisor for guidance.
CATEGORIES
OF REPAIRS
REPAIR DESCRIPTION
1. Weld or Braze Repair This repair excludes detail part replacement
2. Blend Repair
3. Dimensional Restoration by Coating or Plating
4. Surface Treatment Repair This repair includes peening, vibratory tumble (e.g.; restoration of surface finish/texture)
Appendix 2 150
CATEGORIES OF REPAIR Req No.
Repair Design Requirements to be Identified and Substantiated. Repair Properties and Requirements to be Identified and Substantiated.
1. Applicable Degradation Modes: Select all that apply based on the function of the part and its operating environment in the engine. This section provides the background for establishing the substantiation requirements.
a. Thermo-mechanical fatigue
b. Oxidation
c. Corrosion
d. Elevated temperature-induced changes (creep, diffusion, ageing, temperature gradients)
e. Wear due to: adhesion, abrasion, corrosion, erosion, cavitation, fretting, oxidation
f. High-cycle fatigue
g. Rubbing, foreign object impact damage, O3 chemical attack, etc.
Appendix 2 151
CATEGORIES OF REPAIR Req No.
Repair Design Requirements to be Identified and Substantiated. Repair Properties and Requirements to be Identified and Substantiated.
2. Select all mechanical, metallurgical, and physical properties of the part affected by the repair design, and assess their impact on the part’s airworthiness:
Mechanical Properties:
a. Stress-Strain
b. Fracture Toughness
c. Fatigue Strength (S-N, Goodman, Dwell Time)
d. Creep
e. Tensile Properties (Yield, Strength, Elongation)
f. Hardness
g. Young’s Modulus
h. Natural Frequencies
Metallurgical Properties:
i. Chemical Composition (Alloy constituents)
j. Microstructure (grain size – shape - boundary precipitates, gamma prime size and volume fraction, etc.)
k. Melting Point
l. Corrosion Resistance
m. Oxidation Resistance
n. Wear Resistance (Consider wear types in (1)(e))
o. Crack Propagation Rate
Physical Properties:
p. Density (weight)
q. Coefficient of Thermal Expansion
r. Refractive Index (X-Rays)
s. Center of Gravity
t. Polar Moment of Inertia
Appendix 2 152
CATEGORIES OF REPAIR Req No.
Repair Design Requirements to be Identified and Substantiated. Repair Properties and Requirements to be Identified and Substantiated.
3. Select all Material Properties/Characteristics for weldments or brazed joints that apply and evaluate them and their interface with the parent metal. The effect of any changes to the part’s metallurgy as a result of welds or braze should be evaluated for airworthiness.
a. Microstructure (grain size, grain shape, grain boundary precipitates, gamma prime size and volume fraction, etc.)
b. Porosity (weldment)
c. Diffusion Zone (brazing)
d. Heat Affected Zone (welding)
4. Select all Coating Properties/Characteristics that apply and evaluate them and their interface with the parent metal. The effect of any changes to the part’s physical and operational capability as a result of the coating should be evaluated for airworthiness.
a. Coating Material Composition
b. Thickness, Coverage & Uniformity
c. Coating and Diffusion Zone Microstructure
d. Coating Hardness
e. Sintering
f. Strip Requirements/Process
g. Residual Stress
h. Resistance to Spalling
i. Thermal Resistance (coefficient of thermal expansion for the coating)
j. Erosion Resistance
k. Bonding (interface contamination)
l. Hydrogen Embrittlement (plating)
m. Compatibility with Base Material/Other Coatings
5. Select Surface Treatment that applies (without material removal) and evaluate effect(s), if any, on airworthiness:
a. Burnishing
b. Peening
c. Butterfly Polish
d. Mass Media Finishing
Appendix 2 153
CATEGORIES OF REPAIR Req No.
Repair Properties & Requirement to be Identified and Substantiated.
6. Evaluate any degradation in the part’s function or durability due to the following processes, when applicable, and assess its impact, if any, on existing ICAs.
a. Machining, Milling, Broaching, or Grinding
b. Non-traditional Machining
c. Welding, Brazing or Coating
d. Straightening, Re-twisting, Reforming
e. Blending
f. Honing
g. Lapping
h. Grit Blast
i. Stripping
j. Cleaning (chemical, power flash, ultrasonic)
k. Residual Plating, Stripping, or Cleaning Agents
l. Stress Intensity Factor (Kt)
m. Heat Treatment (time, temp, atmosphere, etc.)
n. Plating
o. Dimensional Short-falls
p. Repetitive or Conflicting Repairs Contamination
Appendix 2 154
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
7. Establish the Applicability of the Repair and the Repair Processing Sequence or evaluate any changes to an existing repair sequence for potential impact on the airworthiness of the part.
8. Select all that may be potentially affected by the repair design, and evaluate system effect(s):
a. Structural Strength, including major load paths
b. Heat Transfer
c. Secondary Airflow
d. Aerodynamics
e. Weight
f. Center of Gravity
g. Moment of Weight
Critical Measurable Characteristics
9. Establish Measurable Characteristics and the allowable tolerances for the repaired part features and for any replacement detail(s) and give due consideration to mating part(s):
a. Surface finish/texture
b. Shotpeen intensity/coverage
c. Bearing bore dimensions and location characteristics
d. Pressure strength test
e. Flow capacity test
f. Dimensions, including heat distortion effects roundness flatness parallelism concentricity true position tolerances edge distance requirements finish dimensions requirements
g. Airfoil profile leading & trailing edge contours concave & convex contours thickness chord & tip length twist/lean/bow
Critical Measurable Characteristics
10. Spindle (Trunnion) Diameter
11. Outer Spindle (Trunnion) to Lever Seating Flat
12. Outer Spindle (Trunnion) to Inner Spindle (Trunnion)
13. Outer Spindle (Trunnion) to Inner Spindle (Trunnion) Concentricity
Appendix 2 155
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated, Cont’d.
4 Repair Process Capability Technical Substantiation Requirements
14. Technical Plan with Significant Operations Identified
15. Process Demonstration (including variability requirements)
16. Part Demonstration/Inspection
17. Manufacturing requirements for fabrication of repair details or replacement sections used to accomplish repair:
Drawings/Specifications Quality Requirements Source Substantiation Requirements
Applicable 14 CFR Part 33 Requirements Subpart A – General
18. 33.4 Instructions for Continuous Airworthiness (ICA's)
19. 33.5 Instruction manual for installing and operating the engine
20. 33.7 Engine ratings and operating limitations
21. 33.8 Selection of engine power and thrust ratings Subpart B – Design and Construction;
General
22. 33.14 Start-stop cyclic stress (low cycle fatigue)
23. 33.15 Materials
24. 33.17 Fire prevention
25. 33.19 Durability(Note that 33.19 is associated with 33.27; 33.63; 33.83; 33.87; 33.88; and
33.90)
26. 33.21 Engine cooling
27. 33.23 Engine mounting attachments and structure
28. 33.25 Accessory attachments
29. 33.27 Turbine, compressor, fan, and turbosupercharger rotors
30. 33.28 Electrical and electronic control systems
31. 33.29 Instrument connection Subpart E – Design and Construction;
Turbine Aircraft Engines
32. 33.62 Stress Analysis
33. 33.63 Vibration
Appendix 2 156
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
4 Subpart E – Design and Construction;
Turbine Aircraft Engines
34. 33.65 Surge and stall characteristics (Note 2)
35. 33.66 Bleed air system
36. 33.67 Fuel system
37. 33.68 Induction system icing (operability aspects) (Note 2)
38. 33.69 Ignitions system
39. 33.71 Lubrication system
40. 33.72 Hydraulic actuating systems
41. 33.73 Power or thrust response
42. 33.74 Continued rotation
43. 33.75 Safety analysis
44. 33.76 Bird ingestion (operability aspects of ingestion)
45. 33.77 Foreign object ingestion (operability aspects of ingestion)
46. 33.78 Rain and hail ingestion
47. 33.79 Fuel burning thrust augmentor Subpart F – Block Tests; Turbine Aircraft Engines
48. 33.83 Vibration test
49. 33.85 Calibration tests
50. 33.87 Endurance test
51. 33.88 Engine overtemperature test
52. 33.89 Operation test (Note 2)
53. 33.90 Initial maintenance inspection
54. 33.91 Engine component tests (HCF/LCF bench testing)