European Aviation Safety Agency Notice of Proposed Amendment 2015-07 Use of comparative analysis when showing compliance with SLD icing specifications RMT.0572 — 12.6.2015 EXECUTIVE SUMMARY Rulemaking task RMT.0058 aims to develop new CS-25 certification specifications for flight in icing conditions which were introduced through Amendment 16 of CS-25. A new Appendix O environmental standard representing Supercooled Large Drop (SLD) icing conditions has been created. These SLD icing conditions are therefore part of the certification specifications related to the ice protection of the aeroplane systems and equipment, powerplant and Auxiliary Power Unit (APU), as well as specifications related to aeroplane performance and handling qualities. This Notice of Proposed Amendment (NPA) addresses a need identified by the Agency during the development of rulemaking task RMT.0058, i.e. to have the possibility of taking credit from previously certified large aeroplane type designs having proven to safely operate in SLD icing conditions. The specific objective is to introduce an acceptable means of compliance which may be used by applicants in order to show compliance with the certification specifications related to SLD icing conditions. To this end, this NPA proposes changes to CS-25 Book 1 and Book 2 to enable the use of a means of compliance based on comparative analysis when showing compliance with SLD-related specifications. The proposed changes are expected to maintain safety while increasing cost-effectiveness and facilitating the certification process. Applicability Process map Affected ED Decision 2003/2/RM Concept Paper: No regulations Certification specifications, including Terms of Reference: 28.1.2013 and decisions: airworthiness codes and acceptable Rulemaking group: Yes means of compliance, for large RIA type: Light aeroplanes (‘CS-25’) Technical consultation Affected during NPA drafting: No stakeholders: Large aeroplane manufacturers Duration of NPA consultation: 3 months Driver/origin: New CS-25 provisions for flight in icing Review group: Yes conditions introduced through Focussed consultation: No Amendment 16 Publication date of the Opinion: N/A Request from industry Publication date of the Decision: 2016/Q2 Reference: NPA 2011-03; CRD 2011-03; NPA 2012- 22; CRD 2012-22 TE.RPRO.00034-004 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified. Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/Internet. Page 1 of 53 An agency o the European Union European Aviation Safety Agency NPA 2015-07 Table of contents Table of contents 1. Procedural information .................................................................................................................................... 4 1.1. The rule development procedure............................................................................................................ 4 1.2. The structure of this NPA and related documents .................................................................................. 4 1.3. How to comment on this NPA ................................................................................................................. 4 1.4. The next steps in the procedure .............................................................................................................. 4 2. Explanatory Note .............................................................................................................................................. 5 2.1. Overview of the issues to be addressed .................................................................................................. 5 2.2. Objectives ................................................................................................................................................ 5 2.3. Summary of the Regulatory Impact Assessment (RIA) ............................................................................ 5 2.4. Overview of the proposed amendments ................................................................................................ 5 2.4.1. Definitions........................................................................................................................................ 6 2.4.1.1 Key definitions ............................................................................................................................. 6 2.4.1.2 Additional definitions .................................................................................................................. 7 2.4.2. Comparative analysis as a means of compliance — Explanatory note ........................................... 8 2.4.2.1 Definition of ‘adequately safe fleet history’................................................................................ 9 2.4.2.2 Compliance with CS-25 Certification Specifications relative to flight in the icing conditions defined by Appendix C ................................................................................................................................ 15 2.4.2.3 Analysis of aeroplane design features or margins that are deemed to contribute to the safe fleet history ................................................................................................................................................. 15 2.4.2.4 Additional considerations — Augmenting comparative analysis ............................................. 16 2.4.3. Proposed amendments to CS-25 Book 1 and Book 2 .................................................................... 16 3. Proposed amendments .................................................................................................................................. 18 3.1. Draft Certification Specifications — CS-25 (Draft EASA Decision) ......................................................... 18 4. Regulatory Impact Assessment (RIA) ............................................................................................................. 39 4.1. Issues to be addressed .......................................................................................................................... 39 4.1.1. Safety risk assessment ................................................................................................................... 40 4.1.2. Who is affected? ............................................................................................................................ 40 4.1.3. How could the issue/problem evolve? .......................................................................................... 40 4.2. Objectives .............................................................................................................................................. 40 4.3. Policy options ........................................................................................................................................ 40 4.4. Analysis of impacts ................................................................................................................................ 40 4.4.1. Safety impact ................................................................................................................................. 40 4.4.2. Environmental impact ................................................................................................................... 41 4.4.3. Social impact .................................................................................................................................. 41 4.4.4. Economic impact ........................................................................................................................... 41 4.4.5. General aviation and proportionality issues ................................................................................. 41 4.4.6. Impact on ‘better regulation’ and harmonisation ......................................................................... 41 4.5. Comparison and conclusion .................................................................................................................. 41 4.5.1. Comparison of options .................................................................................................................. 41 4.5.2. Monitoring and ex post evaluation ............................................................................................... 41 5. References ...................................................................................................................................................... 42 5.1. Affected regulations .............................................................................................................................. 42 5.2. Affected CS, AMC and GM ..................................................................................................................... 42 5.3. Reference documents............................................................................................................................ 42 TE.RPRO.00034-004 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified. Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/Internet. Page 2 of 53 An agency o the European Union European Aviation Safety Agency NPA 2015-07 Table of contents 6. Appendices ..................................................................................................................................................... 43 6.1. Appendix 1 — Explanation of the method used to determine the number