Appendix 2 109
CATEGORIES OF REPAIR Req No.
Repair Properties & Requirement 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
d. location characteristics
e. Pressure strength test
f. Flow capacity test
g. Dimensions, including heat distortion effects:
Roundness Flatness Parallelism Concentricity True position tolerances Edge distance requirements Finish dimensions requirements
Airfoil Profile
Leading & Trailing Edge Contours Concave & Convex Contours Thickness Chord & Tip Length Twist/Lean/Bow
Appendix 2 110
CATEGORIES OF REPAIR Repair Properties & Requirement to be Identified and Substantiated.
1 2 3 4 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 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
Appendix 2 111
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
4 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
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
Appendix 2 112
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
4 Subpart E – Design and Construction;
Turbine Aircraft Engines (continued)
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—ice (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 tests
49. 33.85 Calibration tests
50. 33.87 Endurance tests
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)
55. 33.92 Rotor locking tests
56. 33.93 Teardown inspection
57. 33.94 Blade containment and rotor unbalance tests (Weight changes)
58. 33.95 Engine-propeller system tests
59. 33.96 Engine tests in auxiliary power unit (APU) mode
60. 33.97 Thrust reversers
61. 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 2 113 Template 11
REPAIR SUBSTANTIATION CHECKLIST -- MAJOR ENGINE CASES
Categories of Major Cases Part Family. Determine which repair description best fits the repair proposal. If no repair description is appropriate, contact the FAA Advisor for guidance.
CATEGORIES
OF REPAIRS
REPAIR DESCRIPTION
1. Weld or Braze Repair This repair includes detail part replacement
2. Weld or Braze Repair This repair excludes detail part replacement
3. Straightening, Re-twist or Reforming Repair This repair includes dent repair
4. Dimensional Restoration by Coating or Plating
5. Restoration of Adhesives, Bonding Agents, Potting Compound.
6. Bushing or Helicoil Repair
7. Restoration of Protective Coating Includes touch-up coating
8. Assembly and/or Disassembly This repair assembles, disassembles, removes and replaces detail parts, or sub -assemblies without the use of permanent attachment techniques (i.e.; welding or brazing).
Assembly is either bolted or riveted.
9. Remove and Restore Anti-gallant
10. Blend Repair
Appendix 2 114
CATEGORIES OF REPAIRS 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 10
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 2 115
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 10
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 2 116
CATEGORIES OF REPAIRS 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 10
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.
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 2 117
CATEGORIES OF REPAIRS 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 10
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 2 118
CATEGORIES OF REPAIRS Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9 10
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):
Critical Measurable Characteristics
9. Hole dimensions and location characteristics
10. Flange & Case Wall thickness & configuration
11. 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
Repair Process Capability Technical Substantiation Requirements
12. Verification Plan with Significant Operations Identified for Repair Source Qualification
13. Process Demonstration (including variability requirements)
Appendix 2 119
CATEGORIES OF REPAIRS Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9 10
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)
Appendix 2 120
CATEGORIES OF REPAIRS Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9 10
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)
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 turbosupercharger rotors
28. 33.28 Electrical and electronic control systems
29. 33.29 Instrument connection 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
35. 33.68 Induction system icing (operability aspects) (Note 2)
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