MG 23 Automatic Flight Guidance and Control Systems (AFGCS) installation in CS-29 Rotorcraft

• ED Decision 2018/015/R found in: CS-29 Amdt 11 - Large Rotercraft (Feb 2023)

MG 23 Automatic Flight Guidance and Control Systems (AFGCS) installation in CS-29 Rotorcraft ED Decision 2018/015/R This AMC provides further guidance and acceptable means of compliance to supplement FAA AC 29-2C Change 7 MG 23, which is the EASA acceptable means of compliance, as provided for in [AMC 29 General](#_DxCrossRefBm1178331711). However, some aspects of the FAA AC are deemed by EASA to be at variance with EASA’s interpretation or its regulatory system. EASA’s interpretation of these aspects is described below. Paragraphs of FAA AC 29-2C Change 7 MG 23 that are not amended below are considered to be EASA acceptable means of compliance. a. Purpose. (1) The following Radio Technical Commission for Aeronautics (RTCA) documents are considered to be guidance for showing compliance with the relevant certification specifications for the installation of automatic flight control guidance and control systems (AFGCS). (i) RTCA Document DO-325, Minimum Operational Performance Standards (MOPS) for Automatic Flight Guidance and Control Systems and Equipment, issued 8 December 2010. (ii) RTCA Document DO-336, Guidance for Certification of Installed Automatic Flight Guidance and Control Systems (AFGCS) for Part 27/29 Rotorcraft, issued 21 March 2012. (2) RTCA Document DO-325 contains the minimum operational performance standards (MOPS) for AFGCS equipment. DO-336 provides guidance on obtaining installation approval of AFGCS in rotorcraft. It invokes parts of DO-325 as the performance standards that are applicable for the installation of AFGCS equipment in rotorcraft. It provides guidance on conducting a safety assessment. Lastly, DO-336 provides lists of the regulations that can be applicable to an AFGCS installation and potential methods of compliance with those regulations. (3) The guidance contained in DO-336 and DO-325 is not mandatory and provides guidance for showing compliance with the applicable provisions of CS-29. Note: following this guidance alone does not guarantee acceptance by EASA. EASA may require additional substantiation or design changes as a basis for finding compliance. b. Guidance for the use of RTCA Documents DO-325 and DO-336. RTCA Document DO-336 has two primary focus items: to highlight the requirements for a proper safety assessment (Chapter 8) and the compliance demonstration (Chapter 9). Note: each of these should be discussed with EASA very early in the certification programme, and included in the certification plan. c. References. (1) CS-29 provisions <table border="1" cellpadding="0" cellspacing="0" width="536"><thead><tr><td valign="top" width="138"><p><b>Paragraph </b></p></td><td valign="top" width="398"><p><b>Title </b></p></td></tr></thead><tr><td valign="top" width="138"><p>29.671 </p></td><td valign="top" width="398"><p>General. (Control Systems) </p></td></tr><tr><td valign="top" width="138"><p>29.672 </p></td><td valign="top" width="398"><p>Stability augmentation, automatic, and power-operated systems. </p></td></tr><tr><td valign="top" width="138"><p>29.1309 </p></td><td valign="top" width="398"><p>Equipment, systems, and installations. </p></td></tr><tr><td valign="top" width="138"><p>29.1329 </p></td><td valign="top" width="398"><p>Automatic pilot system. </p></td></tr><tr><td valign="top" width="138"><p>29.1335 </p></td><td valign="top" width="398"><p>Flight director systems. </p></td></tr><tr><td valign="top" width="138"><p>Appendix B to CS-29 </p></td><td valign="top" width="398"><p>Airworthiness Criteria for Helicopter Instrument flight </p></td></tr></table> (2) AMC/ACs (available at <http://rgl.faa.gov/>) or <https://www.easa.europa.eu/document-library/certification-specifications/group/amc-20-general-acceptable-means-of-compliance-for-airworthiness-of-products-parts-and-appliances#group-table>) <table border="1" cellpadding="0" cellspacing="0" width="538"><tr><td valign="top" width="140"><p><b>AMC/AC </b></p></td><td valign="top" width="398"><p><b>Title </b></p></td></tr><tr><td valign="top" width="140"><p>20-115D </p></td><td valign="top" width="398"><p>Airborne Software Development Assurance Using EUROCAE ED-12 and RTCA DO-178 </p></td></tr><tr><td valign="top" width="140"><p>20-138 </p></td><td valign="top" width="398"><p>Airworthiness Approval of Positioning and Navigation Systems </p></td></tr><tr><td valign="top" width="140"><p>20-152 </p></td><td valign="top" width="398"><p>RTCA, Inc., Document RTCA/DO-254, Design Assurance Guidance for Airborne Electronic Hardware. </p></td></tr><tr><td valign="top" width="140"><p>21-50 </p></td><td valign="top" width="398"><p>Installation of TSOA Articles and LODA Appliances </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.671</p></td><td valign="top" width="398"><p>Control Systems - General. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.672</p></td><td valign="top" width="398"><p>Stability Augmentation, Automatic, and Power-Operated Systems. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.1309</p></td><td valign="top" width="398"><p>Equipment, Systems, and Installations. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.1329</p></td><td valign="top" width="398"><p>Automatic Pilot System. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.1335</p></td><td valign="top" width="398"><p>Flight Director Systems. </p></td></tr></table> (3) Industry standards (RTCA documents are available at [www.rtca.org](http://www.rtca.org) and SAE international documents are available at [www.sae.org](http://www.sae.org)): <table border="1" cellpadding="0" cellspacing="0" width="539"><tr><td valign="top" width="140"><p><b>Document </b></p></td><td valign="top" width="399"><p><b>Title </b></p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-178 </p></td><td valign="top" width="399"><p>Software Considerations in Airborne Systems and Equipment Certification </p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-254 </p></td><td valign="top" width="399"><p>Design Assurance Guidance for Airborne Electronic Hardware </p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-325 </p></td><td valign="top" width="399"><p>Minimum Operational Performance Standards (MOPS) for Automatic Flight Guidance and Control Systems and Equipment, issued December 8, 2010. </p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-336 </p></td><td valign="top" width="399"><p>Guidance for Certification of Installed Automatic Flight Guidance and Control Systems (AFGCS) for Part 27/29 Rotorcraft, issued March 21, 2012. </p></td></tr><tr><td valign="top" width="140"><p>SAE, International ARP 4754A </p></td><td valign="top" width="399"><p>Guidelines for Development of Civil Aircraft and Systems </p></td></tr><tr><td valign="top" width="140"><p>SAE, International ARP 4761 </p></td><td valign="top" width="399"><p>Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment </p></td></tr></table> [Amdt No: 29/6] --- [[1]](#_ftnref1) The published date represents the date when the consolidated version of the document was generated. [[2]](#_ftnref2) Euro-Lex, Important Legal Notice: <http://eur-lex.europa.eu/content/legal-notice/legal-notice.html>. [[3]](#_ftnref3) It should be noted that rotorcraft tend to have a high centre of gravity due to the position of the engines and gearbox on top of the cabin. It therefore follows that most of the ballast is likely to be required to be installed in these high locations of the model. [[4]](#_ftnref4) Rotors touching the waves can promote capsize, but they can also be a stabilising influence depending on the exact circumstances. Furthermore, rotor blades are often lost during the ditching due to contact with the sea. It is therefore considered acceptable to omit them from the model. [[5]](#_ftnref5) In general the model cannot be permitted to float freely in the basin because in the necessarily long wave test durations, the model would otherwise drift down the basin and out of the calibrated wave region. Constraining the model to remain beam-on to the waves and not float freely is regarded as a conservative approach to the capsize test. . A free-floating test is optional after a specific capsize event, in order to investigate whether the restraint system contributed to the event. It may also be possible to perform a complete free-floating test campaign by combining many short exposures in a wave basin capable of demonstrating a large calibrated wave region. [[6]](#_ftnref6) A sea anchor deployed from the rotorcraft nose is intended to improve stability by keeping the rotorcraft nose into the waves. However, such devices take a significant time to deploy and become effective, and so, their beneficial effect is to be ignored. The rotorcraft model will be restrained to remain beam-on to the waves. [[7]](#_ftnref7) Wind generally has a tendency to redirect the rotorcraft nose into the wind/waves, thus reducing the likelihood of capsize. Therefore, this conservative testing approach does not include a wind simulation. [[8]](#_ftnref8) Each 5-minute exposure might not be independent if, for example, there was flooding of the rotorcraft, progressively degrading its stability. However, in this context, it is considered that the assumption of independence is conservative. [[9]](#_ftnref9) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). [[10]](#_ftnref10) Council Directive 89/686/EEC of 21 December 1989 on the approximation of the laws of the Member States relating to personal protective equipment (OJ L 399, 30.12.1989, p. 18). [[11]](#_ftnref11) Regulation (EU) 2016/425 of the European Parliament and of the Council of 9 March 2016 on personal protective equipment and repealing Council Directive 89/686/EEC (OJ L 81, 31.3.2016, p. 51). [[12]](#_ftnref12) Commission Regulation (EU) No 965/2012 of 5 October 2012 laying down technical requirements and administrative procedures related to air operations pursuant to Regulation (EC) No 216/2008 of the European Parliament and of the Council (OJ L 296, 25.10.2012, p. 1). [[13]](#_ftnref13) Regulation (EC) No 2037/2000 of the European Parliament and of the Council of 29 June 2000 on substances that deplete the ozone layer. [[14]](#_ftnref14) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). --- [[1]](#_ftnref1) The published date represents the date when the consolidated version of the document was generated. [[2]](#_ftnref2) Euro-Lex, Important Legal Notice: <http://eur-lex.europa.eu/content/legal-notice/legal-notice.html>. [[3]](#_ftnref3) It should be noted that rotorcraft tend to have a high centre of gravity due to the position of the engines and gearbox on top of the cabin. It therefore follows that most of the ballast is likely to be required to be installed in these high locations of the model. [[4]](#_ftnref4) Rotors touching the waves can promote capsize, but they can also be a stabilising influence depending on the exact circumstances. Furthermore, rotor blades are often lost during the ditching due to contact with the sea. It is therefore considered acceptable to omit them from the model. [[5]](#_ftnref5) In general the model cannot be permitted to float freely in the basin because in the necessarily long wave test durations, the model would otherwise drift down the basin and out of the calibrated wave region. Constraining the model to remain beam-on to the waves and not float freely is regarded as a conservative approach to the capsize test. . A free-floating test is optional after a specific capsize event, in order to investigate whether the restraint system contributed to the event. It may also be possible to perform a complete free-floating test campaign by combining many short exposures in a wave basin capable of demonstrating a large calibrated wave region. [[6]](#_ftnref6) A sea anchor deployed from the rotorcraft nose is intended to improve stability by keeping the rotorcraft nose into the waves. However, such devices take a significant time to deploy and become effective, and so, their beneficial effect is to be ignored. The rotorcraft model will be restrained to remain beam-on to the waves. [[7]](#_ftnref7) Wind generally has a tendency to redirect the rotorcraft nose into the wind/waves, thus reducing the likelihood of capsize. Therefore, this conservative testing approach does not include a wind simulation. [[8]](#_ftnref8) Each 5-minute exposure might not be independent if, for example, there was flooding of the rotorcraft, progressively degrading its stability. However, in this context, it is considered that the assumption of independence is conservative. [[9]](#_ftnref9) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). [[10]](#_ftnref10) Council Directive 89/686/EEC of 21 December 1989 on the approximation of the laws of the Member States relating to personal protective equipment (OJ L 399, 30.12.1989, p. 18). [[11]](#_ftnref11) Regulation (EU) 2016/425 of the European Parliament and of the Council of 9 March 2016 on personal protective equipment and repealing Council Directive 89/686/EEC (OJ L 81, 31.3.2016, p. 51). [[12]](#_ftnref12) Commission Regulation (EU) No 965/2012 of 5 October 2012 laying down technical requirements and administrative procedures related to air operations pursuant to Regulation (EC) No 216/2008 of the European Parliament and of the Council (OJ L 296, 25.10.2012, p. 1). [[13]](#_ftnref13) Regulation (EC) No 2037/2000 of the European Parliament and of the Council of 29 June 2000 on substances that deplete the ozone layer. [[14]](#_ftnref14) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). MG 23 Automatic Flight Guidance and Control Systems (AFGCS) installation in CS-29 Rotorcraft ED Decision 2018/015/R This AMC provides further guidance and acceptable means of compliance to supplement FAA AC 29-2C Change 7 MG 23, which is the EASA acceptable means of compliance, as provided for in [AMC 29 General](#_DxCrossRefBm1513259330). However, some aspects of the FAA AC are deemed by EASA to be at variance with EASA’s interpretation or its regulatory system. EASA’s interpretation of these aspects is described below. Paragraphs of FAA AC 29-2C Change 7 MG 23 that are not amended below are considered to be EASA acceptable means of compliance. a. Purpose. (1) The following Radio Technical Commission for Aeronautics (RTCA) documents are considered to be guidance for showing compliance with the relevant certification specifications for the installation of automatic flight control guidance and control systems (AFGCS). (i) RTCA Document DO-325, Minimum Operational Performance Standards (MOPS) for Automatic Flight Guidance and Control Systems and Equipment, issued 8 December 2010. (ii) RTCA Document DO-336, Guidance for Certification of Installed Automatic Flight Guidance and Control Systems (AFGCS) for Part 27/29 Rotorcraft, issued 21 March 2012. (2) RTCA Document DO-325 contains the minimum operational performance standards (MOPS) for AFGCS equipment. DO-336 provides guidance on obtaining installation approval of AFGCS in rotorcraft. It invokes parts of DO-325 as the performance standards that are applicable for the installation of AFGCS equipment in rotorcraft. It provides guidance on conducting a safety assessment. Lastly, DO-336 provides lists of the regulations that can be applicable to an AFGCS installation and potential methods of compliance with those regulations. (3) The guidance contained in DO-336 and DO-325 is not mandatory and provides guidance for showing compliance with the applicable provisions of CS-29. Note: following this guidance alone does not guarantee acceptance by EASA. EASA may require additional substantiation or design changes as a basis for finding compliance. b. Guidance for the use of RTCA Documents DO-325 and DO-336. RTCA Document DO-336 has two primary focus items: to highlight the requirements for a proper safety assessment (Chapter 8) and the compliance demonstration (Chapter 9). Note: each of these should be discussed with EASA very early in the certification programme, and included in the certification plan. c. References. (1) CS-29 provisions <table border="1" cellpadding="0" cellspacing="0" width="536"><thead><tr><td valign="top" width="138"><p><b>Paragraph </b></p></td><td valign="top" width="398"><p><b>Title </b></p></td></tr></thead><tr><td valign="top" width="138"><p>29.671 </p></td><td valign="top" width="398"><p>General. (Control Systems) </p></td></tr><tr><td valign="top" width="138"><p>29.672 </p></td><td valign="top" width="398"><p>Stability augmentation, automatic, and power-operated systems. </p></td></tr><tr><td valign="top" width="138"><p>29.1309 </p></td><td valign="top" width="398"><p>Equipment, systems, and installations. </p></td></tr><tr><td valign="top" width="138"><p>29.1329 </p></td><td valign="top" width="398"><p>Automatic pilot system. </p></td></tr><tr><td valign="top" width="138"><p>29.1335 </p></td><td valign="top" width="398"><p>Flight director systems. </p></td></tr><tr><td valign="top" width="138"><p>Appendix B to CS-29 </p></td><td valign="top" width="398"><p>Airworthiness Criteria for Helicopter Instrument flight </p></td></tr></table> (2) AMC/ACs (available at <http://rgl.faa.gov/>) or <https://www.easa.europa.eu/document-library/certification-specifications/group/amc-20-general-acceptable-means-of-compliance-for-airworthiness-of-products-parts-and-appliances#group-table>) <table border="1" cellpadding="0" cellspacing="0" width="538"><tr><td valign="top" width="140"><p><b>AMC/AC </b></p></td><td valign="top" width="398"><p><b>Title </b></p></td></tr><tr><td valign="top" width="140"><p>20-115D </p></td><td valign="top" width="398"><p>Airborne Software Development Assurance Using EUROCAE ED-12 and RTCA DO-178 </p></td></tr><tr><td valign="top" width="140"><p>20-138 </p></td><td valign="top" width="398"><p>Airworthiness Approval of Positioning and Navigation Systems </p></td></tr><tr><td valign="top" width="140"><p>20-152 </p></td><td valign="top" width="398"><p>RTCA, Inc., Document RTCA/DO-254, Design Assurance Guidance for Airborne Electronic Hardware. </p></td></tr><tr><td valign="top" width="140"><p>21-50 </p></td><td valign="top" width="398"><p>Installation of TSOA Articles and LODA Appliances </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.671</p></td><td valign="top" width="398"><p>Control Systems - General. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.672</p></td><td valign="top" width="398"><p>Stability Augmentation, Automatic, and Power-Operated Systems. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.1309</p></td><td valign="top" width="398"><p>Equipment, Systems, and Installations. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.1329</p></td><td valign="top" width="398"><p>Automatic Pilot System. </p></td></tr><tr><td valign="top" width="140"><p>29-2C, Section 29.1335</p></td><td valign="top" width="398"><p>Flight Director Systems. </p></td></tr></table> (3) Industry standards (RTCA documents are available at [www.rtca.org](http://www.rtca.org) and SAE international documents are available at [www.sae.org](http://www.sae.org)): <table border="1" cellpadding="0" cellspacing="0" width="539"><tr><td valign="top" width="140"><p><b>Document </b></p></td><td valign="top" width="399"><p><b>Title </b></p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-178 </p></td><td valign="top" width="399"><p>Software Considerations in Airborne Systems and Equipment Certification </p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-254 </p></td><td valign="top" width="399"><p>Design Assurance Guidance for Airborne Electronic Hardware </p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-325 </p></td><td valign="top" width="399"><p>Minimum Operational Performance Standards (MOPS) for Automatic Flight Guidance and Control Systems and Equipment, issued December 8, 2010. </p></td></tr><tr><td valign="top" width="140"><p>RTCA/ DO-336 </p></td><td valign="top" width="399"><p>Guidance for Certification of Installed Automatic Flight Guidance and Control Systems (AFGCS) for Part 27/29 Rotorcraft, issued March 21, 2012. </p></td></tr><tr><td valign="top" width="140"><p>SAE, International ARP 4754A </p></td><td valign="top" width="399"><p>Guidelines for Development of Civil Aircraft and Systems </p></td></tr><tr><td valign="top" width="140"><p>SAE, International ARP 4761 </p></td><td valign="top" width="399"><p>Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment </p></td></tr></table> [Amdt No: 29/6] --- [[1]](#_ftnref1) The published date represents the date when the consolidated version of the document was generated. [[2]](#_ftnref2) Euro-Lex, Important Legal Notice: <http://eur-lex.europa.eu/content/legal-notice/legal-notice.html>. [[3]](#_ftnref3) It should be noted that rotorcraft tend to have a high centre of gravity due to the position of the engines and gearbox on top of the cabin. It therefore follows that most of the ballast is likely to be required to be installed in these high locations of the model. [[4]](#_ftnref4) Rotors touching the waves can promote capsize, but they can also be a stabilising influence depending on the exact circumstances. Furthermore, rotor blades are often lost during the ditching due to contact with the sea. It is therefore considered acceptable to omit them from the model. [[5]](#_ftnref5) In general the model cannot be permitted to float freely in the basin because in the necessarily long wave test durations, the model would otherwise drift down the basin and out of the calibrated wave region. Constraining the model to remain beam-on to the waves and not float freely is regarded as a conservative approach to the capsize test. . A free-floating test is optional after a specific capsize event, in order to investigate whether the restraint system contributed to the event. It may also be possible to perform a complete free-floating test campaign by combining many short exposures in a wave basin capable of demonstrating a large calibrated wave region. [[6]](#_ftnref6) A sea anchor deployed from the rotorcraft nose is intended to improve stability by keeping the rotorcraft nose into the waves. However, such devices take a significant time to deploy and become effective, and so, their beneficial effect is to be ignored. The rotorcraft model will be restrained to remain beam-on to the waves. [[7]](#_ftnref7) Wind generally has a tendency to redirect the rotorcraft nose into the wind/waves, thus reducing the likelihood of capsize. Therefore, this conservative testing approach does not include a wind simulation. [[8]](#_ftnref8) Each 5-minute exposure might not be independent if, for example, there was flooding of the rotorcraft, progressively degrading its stability. However, in this context, it is considered that the assumption of independence is conservative. [[9]](#_ftnref9) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). [[10]](#_ftnref10) Council Directive 89/686/EEC of 21 December 1989 on the approximation of the laws of the Member States relating to personal protective equipment (OJ L 399, 30.12.1989, p. 18). [[11]](#_ftnref11) Regulation (EU) 2016/425 of the European Parliament and of the Council of 9 March 2016 on personal protective equipment and repealing Council Directive 89/686/EEC (OJ L 81, 31.3.2016, p. 51). [[12]](#_ftnref12) Commission Regulation (EU) No 965/2012 of 5 October 2012 laying down technical requirements and administrative procedures related to air operations pursuant to Regulation (EC) No 216/2008 of the European Parliament and of the Council (OJ L 296, 25.10.2012, p. 1). [[13]](#_ftnref13) Regulation (EC) No 2037/2000 of the European Parliament and of the Council of 29 June 2000 on substances that deplete the ozone layer. [[14]](#_ftnref14) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). --- [[1]](#_ftnref1) The published date represents the date when the consolidated version of the document was generated. [[2]](#_ftnref2) Euro-Lex, Important Legal Notice: <http://eur-lex.europa.eu/content/legal-notice/legal-notice.html>. [[3]](#_ftnref3) It should be noted that rotorcraft tend to have a high centre of gravity due to the position of the engines and gearbox on top of the cabin. It therefore follows that most of the ballast is likely to be required to be installed in these high locations of the model. [[4]](#_ftnref4) Rotors touching the waves can promote capsize, but they can also be a stabilising influence depending on the exact circumstances. Furthermore, rotor blades are often lost during the ditching due to contact with the sea. It is therefore considered acceptable to omit them from the model. [[5]](#_ftnref5) In general the model cannot be permitted to float freely in the basin because in the necessarily long wave test durations, the model would otherwise drift down the basin and out of the calibrated wave region. Constraining the model to remain beam-on to the waves and not float freely is regarded as a conservative approach to the capsize test. . A free-floating test is optional after a specific capsize event, in order to investigate whether the restraint system contributed to the event. It may also be possible to perform a complete free-floating test campaign by combining many short exposures in a wave basin capable of demonstrating a large calibrated wave region. [[6]](#_ftnref6) A sea anchor deployed from the rotorcraft nose is intended to improve stability by keeping the rotorcraft nose into the waves. However, such devices take a significant time to deploy and become effective, and so, their beneficial effect is to be ignored. The rotorcraft model will be restrained to remain beam-on to the waves. [[7]](#_ftnref7) Wind generally has a tendency to redirect the rotorcraft nose into the wind/waves, thus reducing the likelihood of capsize. Therefore, this conservative testing approach does not include a wind simulation. [[8]](#_ftnref8) Each 5-minute exposure might not be independent if, for example, there was flooding of the rotorcraft, progressively degrading its stability. However, in this context, it is considered that the assumption of independence is conservative. [[9]](#_ftnref9) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). [[10]](#_ftnref10) Council Directive 89/686/EEC of 21 December 1989 on the approximation of the laws of the Member States relating to personal protective equipment (OJ L 399, 30.12.1989, p. 18). [[11]](#_ftnref11) Regulation (EU) 2016/425 of the European Parliament and of the Council of 9 March 2016 on personal protective equipment and repealing Council Directive 89/686/EEC (OJ L 81, 31.3.2016, p. 51). [[12]](#_ftnref12) Commission Regulation (EU) No 965/2012 of 5 October 2012 laying down technical requirements and administrative procedures related to air operations pursuant to Regulation (EC) No 216/2008 of the European Parliament and of the Council (OJ L 296, 25.10.2012, p. 1). [[13]](#_ftnref13) Regulation (EC) No 2037/2000 of the European Parliament and of the Council of 29 June 2000 on substances that deplete the ozone layer. [[14]](#_ftnref14) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). ##### MG 23 Automatic Flight Guidance and Control Systems (AFGCS) installation in CS-29 Rotorcraft *ED Decision 2018/015/R* This AMC provides further guidance and acceptable means of compliance to supplement FAA AC 29-2C Change 7 MG 23, which is the EASA acceptable means of compliance, as provided for in [AMC 29 General](#_DxCrossRefBm1685772176). However, some aspects of the FAA AC are deemed by EASA to be at variance with EASA’s interpretation or its regulatory system. EASA’s interpretation of these aspects is described below. Paragraphs of FAA AC 29-2C Change 7 MG 23 that are not amended below are considered to be EASA acceptable means of compliance. a. Purpose. (1) The following Radio Technical Commission for Aeronautics (RTCA) documents are considered to be guidance for showing compliance with the relevant certification specifications for the installation of automatic flight control guidance and control systems (AFGCS). (i) RTCA Document DO-325, *Minimum Operational Performance Standards (MOPS) for Automatic Flight Guidance and Control Systems and Equipment*, issued 8 December 2010. (ii) RTCA Document DO-336, *Guidance for Certification of Installed Automatic Flight Guidance and Control Systems (AFGCS) for Part 27/29 Rotorcraft*, issued 21 March 2012. (2) RTCA Document DO-325 contains the minimum operational performance standards (MOPS) for AFGCS equipment. DO-336 provides guidance on obtaining installation approval of AFGCS in rotorcraft. It invokes parts of DO-325 as the performance standards that are applicable for the installation of AFGCS equipment in rotorcraft. It provides guidance on conducting a safety assessment. Lastly, DO-336 provides lists of the regulations that can be applicable to an AFGCS installation and potential methods of compliance with those regulations. (3) The guidance contained in DO-336 and DO-325 is not mandatory and provides guidance for showing compliance with the applicable provisions of CS-29. Note: following this guidance alone does not guarantee acceptance by EASA. EASA may require additional substantiation or design changes as a basis for finding compliance. b. Guidance for the use of RTCA Documents DO-325 and DO-336. RTCA Document DO-336 has two primary focus items: to highlight the requirements for a proper safety assessment (Chapter 8) and the compliance demonstration (Chapter 9). Note: each of these should be discussed with EASA very early in the certification programme, and included in the certification plan. c. References. (1) CS-29 provisions <table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0"> <col/> <col/> <thead> <tr valign="top"> <td bgcolor="#808080"><p align="center"> <b>Paragraph </b> </p> </td> <td bgcolor="#808080"><p align="center"> <b>Title </b> </p> </td> </tr> </thead> <tbody> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29.671 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> General. (Control Systems) </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29.672 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Stability augmentation, automatic, and power-operated systems. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29.1309 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Equipment, systems, and installations. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29.1329 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Automatic pilot system. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29.1335 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Flight director systems. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> Appendix B to CS-29 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Airworthiness Criteria for Helicopter Instrument flight </p> </td> </tr> </tbody> </table> (2) AMC/ACs (available at http://rgl.faa.gov/) or <https://www.easa.europa.eu/document-library/certification-specifications/group/amc-20-general-acceptable-means-of-compliance-for-airworthiness-of-products-parts-and-appliances>) <table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0"> <col/> <col/> <tr valign="top"> <td bgcolor="#808080"><p align="center"> <b>AMC/AC </b> </p> </td> <td bgcolor="#808080"><p align="center"> <b>Title </b> </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 20-115D </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Airborne Software Development Assurance Using EUROCAE ED-12 and RTCA DO-178 </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 20-138 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Airworthiness Approval of Positioning and Navigation Systems </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 20-152 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> RTCA, Inc., Document RTCA/DO-254, Design Assurance Guidance for Airborne Electronic Hardware. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 21-50 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Installation of TSOA Articles and LODA Appliances </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29-2C, Section 29.671</p> </td> <td bgcolor="#d9d9d9"><p align="center"> Control Systems - General. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29-2C, Section 29.672</p> </td> <td bgcolor="#d9d9d9"><p align="center"> Stability Augmentation, Automatic, and Power-Operated Systems. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29-2C, Section 29.1309</p> </td> <td bgcolor="#d9d9d9"><p align="center"> Equipment, Systems, and Installations. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29-2C, Section 29.1329</p> </td> <td bgcolor="#d9d9d9"><p align="center"> Automatic Pilot System. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> 29-2C, Section 29.1335</p> </td> <td bgcolor="#d9d9d9"><p align="center"> Flight Director Systems. </p> </td> </tr> </table> (3) Industry standards (RTCA documents are available at [www.rtca.org](http://www.rtca.org/) and SAE international documents are available at [www.sae.org](http://www.sae.org/)): <table bgcolor="#d9d9d9" cellpadding="7" cellspacing="0"> <col/> <col/> <tr valign="top"> <td bgcolor="#808080"><p align="center"> <b>Document </b> </p> </td> <td bgcolor="#808080"><p align="center"> <b>Title </b> </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> RTCA/ DO-178 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Software Considerations in Airborne Systems and Equipment Certification </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> RTCA/ DO-254 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Design Assurance Guidance for Airborne Electronic Hardware </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> RTCA/ DO-325 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Minimum Operational Performance Standards (MOPS) for Automatic Flight Guidance and Control Systems and Equipment, issued December 8, 2010. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> RTCA/ DO-336 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Guidance for Certification of Installed Automatic Flight Guidance and Control Systems (AFGCS) for Part 27/29 Rotorcraft, issued March 21, 2012. </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> SAE, International ARP 4754A </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Guidelines for Development of Civil Aircraft and Systems </p> </td> </tr> <tr valign="top"> <td bgcolor="#d9d9d9"><p align="center"> SAE, International ARP 4761 </p> </td> <td bgcolor="#d9d9d9"><p align="center"> Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment </p> </td> </tr> </table> [Amdt No: 29/6] --- [[1]](#_ftnref1) The published date represents the date when the consolidated version of the document was generated. [[2]](#_ftnref2) Euro-Lex, Important Legal Notice: <http://eur-lex.europa.eu/content/legal-notice/legal-notice.html>. [[3]](#_ftnref3) The published date represents the date when the consolidated version of the EAR book was generated. [[4]](#_ftnref4) Euro-Lex, Important Legal Notice: <http://eur-lex.europa.eu/content/legal-notice/legal-notice.html>. [[5]](#_ftnref5) It should be noted that rotorcraft tend to have a high centre of gravity due to the position of the engines and gearbox on top of the cabin. It therefore follows that most of the ballast is likely to be required to be installed in these high locations of the model. [[6]](#_ftnref6) Rotors touching the waves can promote capsize, but they can also be a stabilising influence depending on the exact circumstances. Furthermore, rotor blades are often lost during the ditching due to contact with the sea. It is therefore considered acceptable to omit them from the model. [[7]](#_ftnref7) In general the model cannot be permitted to float freely in the basin because in the necessarily long wave test durations, the model would otherwise drift down the basin and out of the calibrated wave region. Constraining the model to remain beam-on to the waves and not float freely is regarded as a conservative approach to the capsize test. . A free-floating test is optional after a specific capsize event, in order to investigate whether the restraint system contributed to the event. It may also be possible to perform a complete free-floating test campaign by combining many short exposures in a wave basin capable of demonstrating a large calibrated wave region. [[8]](#_ftnref8) A sea anchor deployed from the rotorcraft nose is intended to improve stability by keeping the rotorcraft nose into the waves. However, such devices take a significant time to deploy and become effective, and so, their beneficial effect is to be ignored. The rotorcraft model will be restrained to remain beam-on to the waves. [[9]](#_ftnref9) Wind generally has a tendency to redirect the rotorcraft nose into the wind/waves, thus reducing the likelihood of capsize. Therefore, this conservative testing approach does not include a wind simulation. [[10]](#_ftnref10) Each 5-minute exposure might not be independent if, for example, there was flooding of the rotorcraft, progressively degrading its stability. However, in this context, it is considered that the assumption of independence is conservative. [[11]](#_ftnref11) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). [[12]](#_ftnref12) Council Directive 89/686/EEC of 21 December 1989 on the approximation of the laws of the Member States relating to personal protective equipment (OJ L 399, 30.12.1989, p. 18). [[13]](#_ftnref13) Regulation (EU) 2016/425 of the European Parliament and of the Council of 9 March 2016 on personal protective equipment and repealing Council Directive 89/686/EEC (OJ L 81, 31.3.2016, p. 51). [[14]](#_ftnref14) Commission Regulation (EU) No 965/2012 of 5 October 2012 laying down technical requirements and administrative procedures related to air operations pursuant to Regulation (EC) No 216/2008 of the European Parliament and of the Council (OJ L 296, 25.10.2012, p. 1). [[15]](#_ftnref15) Regulation (EC) No 2037/2000 of the European Parliament and of the Council of 29 June 2000 on substances that deplete the ozone layer. [[16]](#_ftnref16) Commission Regulation (EU) No 744/2010 of 18 August 2010 amending Regulation (EC) No 1005/2009 of the European Parliament and of the Council on substances that deplete the ozone layer, with regard to the critical uses of halon (OJ L 218, 19.8.2010, p. 2). [[17]](#_ftnref17) This includes but is not limited to inspection intervals and life limits listed in the ALS of the ICA. Other examples include overhaul intervals, operating time limits and check or inspection intervals, typically listed in Chapter 5 of the ICA, that are essential towards ensuring the safety and reliability of the part/assembly in question. [[18]](#_ftnref18) This refers to applications that are used to indicated to the crew whether, how and/or when specific actions need to be taken in flight, e.g. as a result of a detected incipient failure. [[19]](#_ftnref19) The guidance within this section has been conceived as a reference approach that may be followed for any individual application for credit, focusing on applications that aim at obtaining the maximum credit possible (e.g. completely replace a maintenance task or extend an inspection interval as much as possible). Applicants should deem that commensurate adjustments relative to this guidance may be discussed, considering the specific details of the VHM application for credit, as well as when the same VHM system is used for a number of applications for credit. [[20]](#_ftnref20) All possible functionalities of the ground segment of the VHM system should covered by the verification activities; tests are expected for these verifications. [[21]](#_ftnref21) The VHM application described is depicted between Cases 1 and 2 in Figures 5 and 6 to indicate that some alleviating factors are included but without reaching those required for Case 2. [[22]](#_ftnref22) This is based on the fact that 1E-07 per flight hour is acceptable when the Case 2 criterion for low probability of occurrence of any preceding degraded condition, 1E-05 per flight hour, is demonstrated. In this instance, a probability of occurrence of 1E-04 per flight hour is demonstrated, 1E-01 away from the target. Therefore, it would be reasonable to apply this delta to the proposed alleviated quantitative safety objective. [[23]](#_ftnref23) The VHM application described is depicted between Cases 2 and 3 in Figures 5 and 6 to indicate that some alleviating factors beyond those required for Case 2 are included but without reaching those required for Case 3.