Appendix 2 Subpart E – Design and Construction;
Turbine Aircraft Engines
15. 33.62 Stress analysis Could be affected
16. 33.63 Vibration Could be affected Blade vibration-Design
17. 33.65 Surge and stall characteristics Could be affected Turbine effective area-Operating line migration, Blade-Rub strip interaction
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 blade release-Case containment
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 Blade vibration-
32. 33.85 Calibration tests
33. 33.87 Endurance test Could be affected Blade durability
34. 33.88 Engine over temperature test Could be affected Blade over temperature capability
35. 33.89 Operation test 145
Appendix 2
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) Could be affected Failure of the most critical turbine blade while operating at maximum permissible r.p.m.
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 146
Appendix 2 Template #17: Fuel Filter This template deals with fuel filters which are typically procured under an OEM part number. If the part is listed as a standard part and can be procured commercially, these requirements do not apply.
Seal/seal Media support mesh Epoxy bonds (typical) End caps (typical) Media support Overall Overall height glands Filtration media diameter Anti-rotation tangassembly (typical) Nomenclature for Generic Component Features (all features may not be applicable) 147
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 Seal glands • Form
• O-ring squeeze
• Gland fill/ free volume
• Surface finish
• Edge condition
• Prevent filter bypass
• Seal damage/self generated contamination
• Anti-rotation friction
• Maintenance/seal installation damage
• Dimensional process control and inspection 1-2 Element length • Form/fit • Seal engagement with filter bowl and manifold
• Inadequate filter bowl/manifold thread engagement
• External leak/failure
• Excessive end play/seal wear
• Dimensional process control and inspection 1-3 End caps • Seal gland inside diameter
• Upper/lower seal gland concentricity
• Support core/end cap fit
• Installation damage( upper seal blind assembly)
• Maintenance error/inadequate bowl to manifold engagement
• Material joining/epoxy joint geometry
• Dimensional process control and inspection 1-4 Anti-rotation tang • Form
• Position
• Installation damage
• Excessive wear-self generated contamination
• Dimensional process control and inspection 1-5 Element diameter • Filter element/filter bowl clearance • Fluid velocity/ flow distribution
• Increased pressure drop
• Increased filter rotation/ spinning forces
• Dimensional process control and inspection 148
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 2-1 Filtration rating/ efficiency Greater than 100 per AIR 887 • Critical orifice blockage/engine control malfunction
• Critical valve failure/engine control malfunction
• Accelerated component wear /component and engine failure
• Design capability validation
• Manufacturing acceptance testing 2-2 Filter media surface area/collection sites Filter element capacity during design basis contamination event following impending bypass indication
• Premature filter bypass/control system malfunction • Design capability validation 2-3 Filter media surface area/collection sites Filter element capacity during normal contamination. Normal filter life.
• Premature filter bypass/control system malfunction • Design capability validation 2-4 Filet media surface area Clean element pressure drop • High pressure fuel pump inadequate inlet pressure/ cavitation/inadequate capacity
• Design capability validation
• Manufacturing acceptance testing 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 Media mechanical properties
• Long term durability
• Media retention/migration
• Self generating/control system malfunction
• Release of contamination/control system malfunction
• Design capability validation 3-2 Material joining epoxy
• Long term durability
• Fuel compatibility
• Temperature capability
• Adhesive strength
• Ultimate/tensile strength
• Filter element/media failure
• Self generating contamination/control system malfunction
• Design capability validation 3-3 Environmental resistance
• Oxidation and corrosion resistance
• Bacterial growth resistance
• Filter element/media failure
• Biological growth system fouling
• Stress corrosion cracking
• Design capability validation 149
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 Filtration media manufacture
• Chemical/material composition
• Drying/baking
• Self generating contamination/control system malfunction
• Release of contaminant/control system malfunction
• Process definition and control 4-2 Material joining epoxy • Surface finish
• Surface cleanliness
• Epoxy shelf life/batch quantities
• Curing process temperature and time control
• Filter element/media failure
• Self generating contamination / control system malfunction
• Process definition and control
• Process sampling/destructive testing 4-3 Filter media mesh sheath • Wire mesh sintering process
• Mechanical preparation/ loose ends from mesh
• Stabilization/heat treat
• Filter element / media failure
• Media sheath failure / self generated contamination
• Stress corrosion cracking
• Process definition and control 4-4 Welding and brazing • Effects on base materials
• Weld or braze strength
• Filter element / media failure
• Self generating contamination / control system malfunction
• Process definition and control
• Process sampling/destructive testing 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 • Inlet fluid velocity distribution
• Rotational forces
• Element rotation/spinning
• Media distortion/flow impingement effects
• CFD analysis at maximum flow conditions 5-2 Plugged filter crush resistance
• Support core strength • Filter element/media failure
• Release of contaminants
• Strength analysis at worst case filter differential pressure with 2X safety margin 5-3 Installation dimensional stack up
• Axial clearance
• Full bowl thread engagement/assured
• O-ring fretting/wear minimized
• Radial clearance/seal concentricity upper seal self aligning
• Filter bowl threads not completely engaged /bowl release / thread failure
• Filter crushed during installation / ineffective filtration / self generated contamination
• Dimensional stack-up analyses
• “Murphy proofing” 5-4 “Murphy proof” installation
• Filter element can not be reversed or is fully reversible
• Filter bowl threads not completely engaged /bowl release / thread failure
• Filter crushed during installation / ineffective filtration / self generated contamination
• Dimensional stack-up analyses
• “Murphy proofing” 150
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 Filter rating/ efficiency
• Greater than 100 per AIR 887 • Critical orifice blockage/engine control malfunction
• Critical valve failure/engine control malfunction
• Accelerated component wear/component and engine failures
• Design assurance (glass bead test)
• Product acceptance test 6-2 Filter capacity test
• Filter element capacity during severe contamination event / time from impending bypass indication
• Premature filter bypass/control system malfunction • Design assurance test
• Specific contaminant makeup, concentration and duty cycle 6-3 Filter durability • No media migration or contaminant release during long term exposure to hot fuel
• Filter element/media failure
• Release of contaminants
• Design operating life demonstration at elevated fuel temperatures 6-4 Filter crush test • Support core test • Filter element/media failure
• Release of contaminants
• Design assurance test at greater than 2X maximum filter differential pressure 6-5 Clean element pressure drop
• New filter element pressure drop at maximum fuel flow and specified temperature
• High pressure fuel pump inadequate inlet pressure/cavitation/inadequate pumping capacity
• Design assurance test
• Product acceptance test 151
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
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 Could be affected No fluid leakage
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 152
Appendix 2 Subpart E – Design and Construction;
Turbine Aircraft Engines
15. 33.62 Stress analysis
16. 33.63 Vibration Could be affected
17. 33.65 Surge and stall characteristics
18. 33.66 Bleed air systems
19. 33.67 Fuel system Could be affected Proper flow at temperature extremes
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
26. 33.75 Safety analysis
27. 33.76 Bird ingestion (Operability aspects of ingestion)
28. 33.77 Foreign object ingestion (Operability aspects of ingestion)
29. 33.78 Rain hail ingestion
30. 33.79 Fuel burning thrust augmenter Subpart F – Block Tests; Turbine Aircraft Engines
31. 33.83 Vibration test
32. 33.85 Calibration tests
33. 33.87 Endurance test Could be affected Proper fuel flow
34. 33.88 Engine over temperature test
35. 33.89 Operation test 153
Appendix 2 Subpart F – Block Tests; Turbine Aircraft Engines
36. 33.90 Initial maintenance inspection Could be affected Filter condition
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 154
Appendix 3 APPENDIX 3. REVERSE ENGINEERING DESIGN PROCESS Reverse engineering requires comprehensive comparative tests and analyses to show the proposed PMA part complies with the applicable requirements of part 33 or the standard defined by TSO C77. An outline of a reverse engineering design process for complex parts is provided below with details at each step. While not all proposed PMA parts require all of these steps, the more complex parts will generally use most of them.
1. Research and Background Processes.
a. Visual and dimensional inspection of sample parts (new).
b. Service history review (for example, service bulletins, service difficulty reports (SDRs) and Airworthiness Directives (ADs)).
c. Review of field returned parts (for example, for wear, cracking and erosion).
d. Define interfaces (such as datum structure and fits and clearances).
e. Patent review (consider unique, novel, or subtle design features not detected through the typical reverse engineering process).
f. ICA review (such as cleaning, inspection, key features, repairs and fits and clearances).
g. Similar part drawing review (PMA holder or public domain).
h. Public domain material specification (such as Aerospace Material Specifications and Mil Handbooks).
i. International standards for drawings (such as the American Society of Mechanical Engineers).
j. Standard part drawings (such as gears, fasteners and bearings).
k. Manufacturing technology and sources available to produce the part.
l. Discrepancy review versus available data (outside serviceable limits).
m. Quality evaluation report (quality differences related to the type design suppliers).
2. Technical Data Generation Processes:
a. Dimensions and tolerances (part and mating parts as required).
b. Interface definition.
Appendix 3
c. Surface finish.
d. Break edges and chamfers.
e. Stack-up Analysis.
f. Hidden features (those features lost during assembly or processing of the detail parts).
g. Materials. These include:
• Micro and macrostructure;
• Coatings;
• Plating;
• Material forms (such as bar stock, forging and casting); and
• Material chemistry including trace element requirements.
h. Performance specifications (such as loads, fatigue life and duty cycle).
i. Testing specifications (acceptance tests, functional tests).
j. Non-destructive testing requirements (such as fluorescent penetrant inspection and ultrasonic).
k. Surface enhancements (such as shot peening).
l. Non-conventional machining assessment (such as EDM, laser drilling and chemical milling).
m. Quality requirements (creation of the preliminary inspection plan).
n. Manufacturing process control requirements (substantiated and controlled processes such as material melt practices, plating, heat treat, welding and brazing).
3. Design Verification Processes:
a. Final independent design review.
b. Conformity inspection of prototypes.
c. Testing (functional, operational, and system tests).
d. Inspection and quality assurance requirements.
e. Complete technical data package with test results.
f. Dimensional comparison of prototype with drawing and type design part.