Appendix A A-53 Table A-8. Examples of Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
9. Skid landing gear to wheel landing gear or wheel landing to skid.
Yes No Yes
10. Change of the number of rotor blades.
Yes No Yes
11. Change tail anti-torque device (e.g., tail rotor, ducted fan or other technology).
Yes Yes No
12. Passenger configured helicopter to a Firefighting equipment configured helicopter.
Yes No Yes Depends on the firefighting configuration.
13. Passenger configured helicopter to an agricultural configured helicopter.
Yes No Yes Depends on the agricultural configuration.
14. An initial Category A certification approval to an existing configuration.
No No Yes
Appendix A A-54 Table A-8. Examples of Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
15. IFR upgrades involving installation of upgraded components for new IFR configuration.
No No Yes Changes in architecture concepts, design philosophies, human-machine interface, or flightcrew workload.
16. Human external cargo (HEC) certification approval.
No No Yes Must comply with the latest HEC certification requirements in order to obtain operational approval.
HEC include fatigue, quick release systems, HIRF, one engine inoperative (OEI) performance, and OEI procedures.
17. Reducing the number of pilots for IFR from two to one.
No No Yes
18. An avionics upgrade that changes a federated avionics system to a highly integrated avionics system.
No No Yes This change refers to the avionics system that feeds the output to displays and not the displays themselves.
Appendix A A-55 Table A-8. Examples of Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
19. An avionics upgrade that changes the method of input from the flightcrew, which was not contemplated during the original certification.
No No Yes A change that includes touchscreen technology typically does not invalidate the assumptions used for certification.
A change that incorporates voice activated controls or other novel human-machine interface would likely invalidate the assumptions used for certification.
Appendix A A-56 A.3.3 Table A-9 contains examples of changes that are “not significant” changes for rotorcraft (parts 27 and 29).
Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
1. Emergency floats. No No No Must comply with the specific applicable requirements for emergency floats. This installation, in itself, does not change the rotorcraft configuration, overall performance, or operational capability. Expanding an operating envelope (such as operating altitude and temperature) and mission profile (such as passenger carrying operations to external load operations, flight over water, or operations in snow conditions) are not by themselves so different that the original certification assumptions are no longer valid at the type certificated product level.
Appendix A
Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
2. FLIR or surveillance camera installation.
No No No Additional flight or structural evaluation may be necessary but the change does not alter the basic rotorcraft certification.
3. Helicopter terrain awareness warning system (HTAWS) for operational credit.
No No No Certificated under rotorcraft HTAWS AC guidance material and FAA TSO-C194. Does not alter the basic rotorcraft configuration.
4. Health usage monitoring system (HUMS) for maintenance credit.
No No No Certificated under rotorcraft HUMS AC guidance material.
Does not alter the basic rotorcraft configuration.
A-57
Appendix A A-58 Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
5. Expanded limitations with minimal or no design changes, following further tests/justifications or different mix of limitations (CG limits, oil temperatures, altitude, minimum/ maximum weight, minimum/ maximum external temperatures, speed, engine ratings).
No No No Changes to an operating envelope (such as operating altitude and temperature) and mission profile (such as passenger carrying operations to external load operations, flight over water, or operations in snow conditions) that are not so different that the original certification assumptions remain valid.
6. Change from a single channel FADEC to a dual channel FADEC.
Change does not change the overall product configuration or the original certification assumptions.
7. Installation of a new engine type, equivalent to the former one, leaving aircraft installation and limitations substantially unchanged.
No No No Refer to AC 27-1 or AC 29-2 for guidance. Does not alter the basic rotorcraft configuration, provided there is no additional capacity embedded in the new design.
Appendix A A-59 Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
8. Windscreen installation. No No No Does not change the rotorcraft overall product configuration.
9. Snow skis, “Bear Paws.” No No No Must comply with specific requirements associated with the change. Expanding an operating envelope (such as operating altitude and temperature) and mission profile (such as passenger carrying operations to external load operations, flight over water, or operations in snow conditions) are not by themselves so different that the original certification assumptions are no longer valid at the type certificated product level.
Appendix A A-60 Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
10. External cargo hoist. No No No Must comply with the specific applicable requirements for external loads. This installation, in itself, does not change the rotorcraft configuration, overall performance, or operational capability. Expanding an operating envelope (such as operating altitude and temperature) and mission profile (such as passenger carrying operations to external load operations excluding HEC, flight over water, or operations in snow conditions) are not by themselves so different that the original certification assumptions are no longer valid at the type certificated product level.
Appendix A A-61 Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
11. IFR upgrades involving installation of upgraded components to replace existing components.
No No No Not a rotorcraft-level change.
12. An avionics change from federated electromechanical displays to federated electronic displays.
No No No Changing an electro-mechanical display to an electronic display on a single avionics display is not considered significant.
13. An avionics change replacing an integrated avionics system with another integrated avionics system.
No No No The assumptions used to certify a highly integrated avionics system should be the same for another highly integrated avionics system.
14. Flightdeck replacement of highly integrated and combined electronic display systems with other highly integrated and combined electronic display systems.
No No No Not significant if the architecture concepts, design philosophies, human-machine interface, flightcrew workload design flightdeck assumptions are not impacted.
Appendix A A-62 Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
15. IFR upgrades involving installation of upgraded components for new IFR configuration.
No No No No changes in architecture concepts, design philosophies, human-machine interface, or flightcrew workload.
16. Flightdeck replacement or upgrade of avionics systems in non-appendix “B” (IFR) or non-CAT “A” rotorcraft that can enhance safety or pilot awareness.
No No No
17. Modifications to non-crashworthy fuel systems intended to improve its crashworthiness.
No No No
Appendix A A-63 Table A-9. Examples of Not Significant Changes for Rotorcraft (Parts 27 and 29) (continued) Example Description of change Is there a change to the general configuration?
§ 21.101(b)(1)(i) Is there a change to the principles of construction?
§ 21.101(b)(1)(i) Have the assumptions used for certification been invalidated?
§ 21.101(b)(1)(ii) Notes
18. Changing the hydraulic system from one similar type of fluid to another,
e.g., a fluid change from a highly flammable mineral oil based fluid (MIL-H-5606) to a less flammable synthetic hydrocarbon based fluid (MIL-PRF-87257) No No No
19. A TSO C-127 dynamic seat installed in a helicopter with an existing certification basis prior to addition of § 29.562, Emergency landing dynamic conditions.
No No No
Appendix A A-64 A.4 Examples of Substantial, Significant, and Not Significant Changes for Engines (Parts 33) A.4.1 Table A-10 contains examples of changes that are “substantial” for engines (part 33).
Table A-10. Examples of Substantial Changes for Engines (Part 33) Example Description of Change Notes Turbine Engines
1. Traditional turbofan to geared-fan engine. Proposed change in design is so extensive that a substantially complete investigation of compliance with the applicable regulations is required.
2. Low bypass ratio engine to high bypass ratio engine with an increased inlet area.
Proposed change in design is so extensive that a substantially complete investigation of compliance with the applicable regulations is required.
3. Turbojet to turbofan. Proposed change in design is so extensive that a substantially complete investigation of compliance with the applicable regulations is required.
4. Turbo-shaft to turbo-propeller. Proposed change in design is so extensive that a substantially complete investigation of compliance with the applicable regulations is required.
5. Conventional ducted fan to unducted fan. Proposed change in design is so extensive that a substantially complete investigation of compliance with the applicable regulations is required.
6. Turbine engine for subsonic operation to afterburning engine for supersonic operation.
Proposed change in design is so extensive that a substantially complete investigation of compliance with the applicable regulations is required.