Appendix 2 97
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 98
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. Coating & Plating Material Properties Characteristics & Processes:
a. Deposited Material Composition
b. Thickness, Coverage & Uniformity
c. Microstructure
d. Hardness
e. Sintering
f. Strip Process
g. Residual Stress
h. Lubricant Properties
i. Spalling Resistance
j. Thermal Resistance
k. Erosion Resistance
l. Bonding (Interface Contamination)
m. Environmental Resistance
n. Diffusion Zone
o. Hydrogen Embrittlement Free (Plating)
p. Compatibility With Base Material
Appendix 2 99
CATEGORIES OF REPAIR Req No.
Repair Design Requirements to be Identified and Substantiated. Repair Properties and Requirements to be Identified and Substantiated.
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
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
q. Contamination
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.
Appendix 2 100
CATEGORIES OF REPAIR Req.
No.
Repair Design Requirements to be Identified and Substantiated, Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9 Critical Measurable Characteristics
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
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
h. Leading & Trailing Edge Contours
i. Concave & Convex Contours
j. Thickness
k. Chord & Tip Length
l. Twist/Lean/Bow
Critical Measurable Characteristics
10. Outer Band Rail Functional Fit
11. Inner Band Arc Length
12. Outer Band to Inner Band Dim Relationship
13. Assembled Honeycomb Inner Radius
Appendix 2 101
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
9 Repair Process Capability Technical Substantiation Requirements
14. Verification Plan with Significant Operations Identified for Repair Source Qualification
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
Appendix 2 102
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
9 Repair Process Capability Technical Substantiation Requirements
Subpart B – Design and Construction;
General
29. 33.27 Turbine, compressor, fan, and turbosupercharger
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
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
55. 33.85 Calibration tests
49. 33.87 Endurance test
50. 33.88 Engine overtemperature test
51. 33.89 Operation test (Note 2)
Appendix 2 103
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
52. 33.90 Initial maintenance inspection
53. 33.91 Engine component tests (HCF/LCF bench testing)
54. 33.92 Rotor locking tests
55. 33.93 Teardown inspection
56. 33.94 Blade containment and rotor unbalance tests (weight changes)
57. 33.95 Engine-propeller system tests
58. 33.96 Engine tests in auxiliary power unit (APU) mode
59. 33.97 Thrust reversers
60. 33.99 General conduct of block tests Part 33 -Appendix A – Instructions for Continued Airworthiness
Part 33 -Appendix B- Certification Standard Atmospheric Concentrations of Rain and Hail
Part 34 – Exhaust Emissions
Appendix 2 104 Template 10
REPAIR SUBSTANTIATION CHECKLIST –LOW PRESSURE COMPRESSOR (LPC) – HIGH PRESSER COMPRESSOR (HPC) STATOR PART FAMILY – FIXED VANE TYPE STATORS (CANTILEVERED AT O.D.)
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. Dimensional Restoration by Coating or Plating
2. Weld or Braze Repair This repair excludes detail part replacement
3. Blend Repair
4. Surface Treatment Repair This repair includes peening, vibratory tumble (e.g.; restoration of surface finish/texture)
Appendix 2 105
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 2 106
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 2 107
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
Appendix 2 108
CATEGORIES OF REPAIR Req No.
Repair Properties & Requirement to be Identified and Substantiated.
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
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