Appendix 2 25
CATEGORIES OF REPAIR Req No.
Airworthiness Standards to be Substantiated 1 2 3 4 5 6 7 8 9 10 11 Subpart E – Design and Construction; Turbine Aircraft Engines (continued)
37. 33.75 Safety analysis
38. 33.76 Bird ingestion (operability aspects of ingestion)
39. 33.77 Foreign object ingestion—ice (operability aspects of ingestion)
40. 33.78 Rain and hail ingestion
41. 33.79 Fuel burning thrust augmentor Subpart F – Block Tests; Turbine Aircraft Engines
42. 33.83 Vibration test
43. 33.85 Calibration tests
44. 33.87 Endurance test
45. 33.88 Engine overtemperature test
46. 33.89 Operation test (Note 2)
47. 33.90 Initial maintenance inspection
48. 33.91 Engine component tests (HCF/LCF bench testing)
49. 33.92 Rotor locking tests
50. 33.93 Teardown inspection
51. 33.94 Blade containment and rotor unbalance tests (weight changes)
52. 33.95 Engine-propeller system tests
53. 33.96 Engine tests in auxiliary power unit (APU) mode
54. 33.97 Thrust reversers
55. 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 26 Template 2
REPAIR SUBSTANTIATION CHECKLIST – HIGH PRESSURE TURBINE (HPT)
BLADE PART FAMILY
Categories of HPT Blade Part Family Repair. 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. Overcoat Repair (without stripping)
2. Strip and Re-coat Repair This repair removes and replaces all types of coatings.
3. Weld or Braze Repair (excludes detail parts replacement) Includes restoration of airfoil tip and chord length
4. Weld or Braze Repair Includes detail parts replacement
5. Surface Treatment Repair Including shot-peen, glass bead peen, and vibratory tumble (e.g.; restoration of surface finish/texture).
6. Blend Repair
7. Blade Internal Cavity Cleaning Repair
8. Sulfidation or Corrosion Repair
9. Assembly and/or Disassembly. This repair removes and replaces details parts without the use of permanent attachment techniques (i.e., welding or brazing), but assembly is either bolted or riveted.
Appendix 2 27
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
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.
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:
Appendix 2 28
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 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 29
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
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)
Appendix 2 30
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
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 31
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9
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
Appendix 2 32
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
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
Appendix 2 33
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9 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 Contour Concave & convex contours Thickness Chord & Airfoil Length Twist/Lean/Bow
h. Tip Length
i. Airfoil wall thickness
10. Part Weight:
a. Mass
b. Moment
Appendix 2 34
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9
11. Platform width & (angel wing) Cross Notch/Cross Shroud geometry
12. Cooling (Total flow, flow split, back flow margin, hole exit geometry/angle/location, cross-over hole size, metering plate)
Repair Process Capability Technical Substantiation Requirements
13. Verification Plan with Significant Operations Identified for Repair Source Qualification
14. Process Demonstration (including variability requirements)
15. Part Demonstration/Inspection
16. 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
17. 33.4 Instructions for Continuous Airworthiness (ICA's)
Repair Process Capability Technical Substantiation Requirements
18. 33.5 Instruction manual for installing and operating the engine
19. 33.7 Engine ratings and operating limitations
20. 33.8 Selection of engine power and thrust ratings
Subpart B – Design and Construction;
General
21. 33.14 Start-stop cyclic stress (low cycle fatigue)
Appendix 2 35
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9
22. 33.15 Materials
23. 33.17 Fire prevention
24. 33.19 Durability (Note that 33.19 is associated with 33.27; 33.63; 33.83; 33.87;
33.88; and 33.90)
25. 33.21 Engine cooling
26. 33.23 Engine mounting attachments and structure
27. 33.25 Accessory attachments
28. 33.27 Turbine, compressor, fan, and turbosupercharger rotors
29. 33.28 Electrical and electronic control systems
30. 33.29 Instrument connection Subpart E – Design and Construction;
Turbine Aircraft Engines
31. 33.62 Stress analysis
32. 33.63 Vibration
33. 33.65 Surge and stall characteristics (Note 2)
34. 33.66 Bleed air system
35. 33.67 Fuel system
36. 33.68 Induction system icing (operability aspects) (Note 2)
37. 33.69 Ignitions system
38. 33.71 Lubrication system
39. 33.72 Hydraulic actuating systems
40. 33.73 Power or thrust response
41. 33.74 Continued rotation
42. 33.75 Safety analysis
43. 33.76 Bird ingestion (operability aspects of ingestion)
44. 33.77 Foreign object ingestion—ice (operability aspects of ingestion)
45. 33.78 Rain and hail ingestion
46. 33.79 Fuel burning thrust augmentor
Appendix 2 36
CATEGORIES OF REPAIR Req No.
Repair Properties and Requirements to be Identified and Substantiated.
1 2 3 4 5 6 7 8 9 Subpart F – Block Tests; Turbine Aircraft Engines
47. 33.83 Vibration test
48. 33.85 Calibration tests
49. 33.87 Endurance test
50. 33.88 Engine overtemperature test
51. 33.89 Operation test (Note 2)
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