1. PURPOSE. This advisory circular (AC) provides guidance ...

1 Department of Transportation Federal Aviation Administration advisory circular Subject: SYSTEM SAFETY ANALYSIS AND ASSESSMENT FOR PART 23 AIRPLANES Date: 1/16/09 Initiated by: ACE-100 AC No: This advisory circular (AC) sets forth an acceptable means of showing compliance with Title 14 of the Code of Federal Regulations (14 CFR) (a) and (b) (Amendment 23-49) for equipment, systems, and installations in 14 CFR part 23 airplanes. This AC is not mandatory and does not constitute a regulation. It is issued for guidance purposes and to outline a method of compliance with the rules.

2 An applicant may elect to follow an alternative method, provided the FAA finds it to be an acceptable means of complying with the applicable requirements of 14 CFR. However, if the applicant uses the means described in the AC, they must follow it in all important respects. s/ James E. Jackson Acting Manager, Small Airplane Directorate Aircraft Certification Service 1/16/09 AC TABLE OF CONTENTS Section Page 1.

3 What is the purpose of this AC?.. 1 4. Related regulations and 1 5. 3 6. Regulations and AC 4 7. 7 8. 9. Application of (a), (a)(1), (a)(2), and (a)(3), as adopted by Amendments 23-41 and 14 10. Showing compliance with the requirements of 14 11. Application of (a)(4), as adopted by Amendment 18 12. Application of (b), as adopted by Amendments 23-41 and 19 13. Four certification classes of 19 14. Safety 23 15. Failure 28 16. Assessment 29 17. Assessment of failure condition probabilities and analysis 31 18.

4 Testing and compliance with the requirements of and 32 19. Operational and maintenance 33 21. Software and complex hardware DALs for airborne system and 34 22. Information only note for future 35 APPENDIX 1. PARTIAL LIST OF FUNCTIONAL HAZARD ASSESSMENT (FHA) FOR CONSIDERATION TO MEET 14 CFR PART 23 REQUIREMENTS FOR IFR CLASS I AIRPLANES ..A1 APPENDIX 2. SAMPLE FUNCTIONAL HAZARD ASSESSMENT (FHA) FORMAT ..A2 APPENDIX 3. CALCULATION OF THE AVERAGE PROBABILITY PER FLIGHT iii (and iv) 1/16/09 AC 1.

5 What is the purpose of this AC? a. This AC provides guidance and information for an acceptable means, but not the only means, for showing compliance with the requirements of (a) and (b) (Amendment 23-49) for equipment, systems, and installations in Title 14 Code of Federal Regulations (14 CFR) part 23 airplanes. b. This material is neither mandatory nor regulatory in nature and does not constitute a regulation. It describes acceptable means, but not the only means, for demonstrating compliance with the applicable regulations.

6 We will consider other methods of demonstrating compliance that an applicant may elect to present. While these guidelines are not mandatory, they are derived from extensive FAA and industry experience in determining compliance with the relevant regulations. Whenever an applicant s proposed method of compliance differs from this guidance , the proposal should be coordinated with the Small Airplane Directorate Standards Staff, ACE-110. In addition, if an office believes that an applicant s proposal that meets this guidance should not be approved, that office should coordinate its response with the Small Airplane Directorate Standards Staff, ACE-110.

7 C. Terms such as shall or must are used in this AC only in the sense of ensuring applicability of this particular method of compliance when the acceptable method of compliance described herein is used. The word shall and must is also used in this AC when referring to a specific regulation or guidance that is essential when the applicant uses this AC for the means of compliance. In this case there is no deviation. The word should is used to express a recommendation. Deviation from the specified recommendation may require justification.

8 2. Who does this AC apply to? The guidance provided in this document is directed to airplane manufacturers, modifiers, foreign regulatory authorities, Federal Aviation Administration (FAA) part 23 airplane type certification engineers, and designees. 3. Cancellation. This AC cancels AC , Equipment, Systems, and Installations in Part 23 Airplanes, dated March 12, 1999. It also cancels PS-ACE100-2005-50001, Applying AC 20-152, RTCA, Inc., Document RTCA/DO-254, Design Assurance guidance for Airborne Electronic Hardware, to Title 14 Code of Federal Regulations, Part 23 Aircraft; dated January 26, 2007 4.

9 Related regulations and documents. a. Regulations. Sections and of part 23 (through Amendment 23-49). 1 1/16/09 AC b. ACs, orders, and policy. You may access the ACs, notices, orders, and policy on the FAA website: You may obtain copies of current editions of the following publications free from the Department of Transportation, Subsequent Distribution Office, M-30, Ardmore East Business Center, 3341 Q 75th Avenue, Landover, MD 20785.

10 AC 20-115B RTCA, Inc., Document RTCA/DO-178B AC 20-152 RTCA, Inc., Document RTCA/DO-254, Design Assurance guidance for Airborne Electronic Hardware AC 21-16E RTCA, Inc. Document RTCA/DO-160E, Environmental Conditions and Test Procedures for Airborne Equipment ac 23 -17B Systems and Equipment Guide for Certification of Part 23 Airplanes and Airships AC Installation of Electronic Displays in Part 23 Airplanes AC 20-136A Protection of Aircraft Electrical/Electronic Systems Against the Indirect Effects of Lightning AC 20-158 The Certification of Aircraft Electrical and Electronic Systems for Operation in the High-Intensity Radiated Fields (HIRF)