Composite Structural Modifications

Transcription

1 Composite Structural Modifications By: Cindy Ashforth To: Modification Workshop July 19, 2016

2 Welcome Thank you for attending this workshop Logistics Emergency Exits Tornado Procedures Lavatories Lunch, Breaks, Social Hour Website Survey 2

3 Workshop Goals Develop consensus on applicable regulations Identify challenges in certifying installation of composite parts or modifications of composite structures Identify best practices in certifying installation of composite parts or modifications of composite structures Potential coordination with standards organizations Identify subjects that should be addressed in guidance 3

4 Composite Modifications AC We have created an outline We intend for the AC to cover: Installation of Composite Parts (structural or nonstructural) on Metallic or Composite Structure May or may not require modification of existing structure Modification of Composite Structure (for whatever purpose) Includes interior installations, installing metallic parts on composite structure, repairs, etc. This workshop is an opportunity to discuss what information should be in the guidance and benchmark best industry practices 4

5 Modification AC The following slides present initial thoughts on potential AC content The purpose of this AC is to provide guidance regarding certification requirements of 14 CFR 21, 23, 25, 26, 27, and 29 associated with the alteration or change to type design of composite aircraft structure or installation of composite parts. Examples of the types of modifications, or alterations, that this AC is meant to address are as follows: Modification or alteration of composite structure, such as to install an antenna or winglets. Installation of composite parts (such as antenna, cargo or mission equipment pods, performance enhancing aerodynamic fairings, cowlings, etc.) on metallic or composite structure. At this point we do not intend to address parts 33 or 35 5

6 Modification AC Applicability This AC is applicable to design approval holders and applicants, FAA designees, and other parties approving modifications or alterations to composite aircraft structure or installation of composite parts on composite or metallic structure. As with all advisory material, this AC is not mandatory and does not constitute a regulation. It is issued for guidance purposes and to outline a means of compliance with applicable airworthiness requirements. 6

7 Modification AC Background The use of composites in aircraft structure and modifications to metallic structures has reduced weight without sacrificing structural strength. This has led to an increased use of composite materials in many applications that were traditionally metallic. Examples of modifications include large composite antenna radomes on metallic fuselage, alterations (antenna holes) to composite fuselage, composite winglets, engine cowls, composite skis, floats, camera pods, etc. 7

8 Modification AC Background (continued) Certifying composite materials for use in civil aircraft is not a straightforward task because composite materials are not standardized like metallic materials. Composite design data, such as material properties and design values, processing requirements, and analysis methods, are often proprietary. This presents a challenge for both modifiers and the FAA. Design practices used for structural modifications involving composites vary between projects, inhibiting certification efficiency and making it difficult to maintain a level playing field. 8

9 Modification AC Background (continued) The design data must be fully developed to ensure a quality part, as well as compatibility with existing structures that these parts are installed on. Without access to the original design data, or at least an understanding of the approach used to certify existing composite structure, it is possible that a modifier (STC applicant, DER, Repair Station, Mechanic/Inspector, etc.) may inadvertently introduce a noncompliance. 9

10 Modification AC Structural Modifications Regulatory Requirements The regulations are the same regardless of the materials (exception 2x.571/2x.573). Would like to provide a checklist for projects. Modifications to Metallic Structure What needs to be considered when you modify metallic structure to install composite parts. (thermal mismatch, galvanic corrosion, etc.) Modifications to Composite Structure What needs to be considered when you modify composite structure to install metallic or composite parts. Special Considerations for Pressurized Structure Whether metallic or composite, these things should be considered when modifying pressurized structure, such as fuselage skins. May need additional content for other specialized modifications, such as fuel tanks 10

11 Modification AC Composite Part Requirements General Materials and Processing Allowables and Design Values Development Static Strength Substantiation Damage Tolerance Bird Strike Inspection and Repair Flammability and Smoke Release Etc. This will be for both structural and non-structural parts, including interior components. 11

12 Modification AC Other Considerations (could perhaps retitle installation considerations ) Aeroelastic Instability Systems Interface Lightning Protection Instructions for Continued Airworthiness LOV Etc. Setting Thresholds and Intervals 12

13 Workshop Agenda Tuesday, July 19 Time Subject Speaker 8:00 8:15 Welcome and Introductions Larry Ilcewicz, FAA 8:15 8:45 Overview of proposed AC scope and workshop goals Cindy Ashforth, FAA Session 1: Requirements and Metallic Modifications 8:45 9:30 Modification Experience Simon Waite, EASA 9:30 10:00 Modification Challenges from the CAA NZ Perspective Greg Baum, CAA New Zealand 10:00 10:15 Break 10:15 10:45 Overview of regulatory requirements and Mike Cann, FAA existing guidance and industry documentation 10:45 11:15 Considerations and experiences installing composite parts on metallic structure Ed Davis, Aviation Partners 11:15 11:45 Structural Modifications Classification, Requirements and Certification Aspects Andries Buitenhuis, Fokker Aerostructures 11:45 12:15 Moderated Discussion Andreas Rambalakos, FAA 12:15 1:15 Lunch 13

14 Workshop Agenda Tuesday, July 19 Time Subject Speaker Session 2: Requirements / Practices to Design and Certify Composite Modification Parts 1:15 1:45 Common MRB for Composite Parts Dave McClenahan, McClenahan Engineering 1:45 2:15 Development and Certification of Composite Helicopter Rotor Blades James Van Horn, Van Horn Aviation LLC 2:15 2:45 Requirements / Practices to Design and Ed Goodrich, Nordam Certify Composite Modification Parts 2:45 3:00 Break 3:00 3:30 Special Mission Belly Pods / Radomes Frank Simmons, Gulfstream 3:30 4:00 Moderated Discussion Angie Kostopoulos, FAA 4:00 4:30 Industry Partnerships and International Standards for Certification Efficiency 4:30 5:00 Tour of National Center for Aviation Training 5:00 6:30 Hosted Social Hour John Tomblin, NIAR John Tomblin, NIAR 14

15 Workshop Agenda Wednesday, July 20 Time Subject Speaker Session 3: Requirements for Modifying Composite Structure 8:00 8:30 The Substantiation Dilemma Associated with Major Composite Repairs and Alterations 8:30 9:00 Perspectives on Modifications and Alterations on Modern Composite Airplanes 9:00 9:45 An experimental presentation on the effects of poor design or implementation of modifications involving composite materials 9:45 10:00 Break 10:00 10:30 Design and Process Guidelines for Helicopter Structural Modifications 10:30 11:00 Requirements for Modifications to Composite Structure Jim Epperson, Spirit Aerosystems Paul Brey, Consultant Yeow Ng, NIAR DJ Reddy, Consultant Barry Schroeder, Airbus and Surendra Rajpal, Boeing Eric Chesmar, United Airlines 11:00 11:30 Requirements for Modifications to Composite Structure 11:30 12:00 Moderated Discussion Larry Ilcewicz, FAA 12:00 1:00 Lunch 15

16 Workshop Agenda Wednesday, July 20 Time Subject Speaker Session 4: Special Subjects 1:00 1:40 Repair and Modification of Primary Composite Structural Components - Substantiation Complexities for Non-OEMs Within the Scope of both Field Approvals and STC Projects Steve Forness, Air Flight Technical 1:40 2:00 Background: Part 23, 21.9 NPRM Lester Cheng, FAA 2:00 2:30 Limit of Validity, Repairs, ModificatioAns, Composites, and the Aviation Advisory Rulemaking Committee 2:30 3:10 The Impact of Electromagnetic Effects on Composite Structure Design and Repair 3:10 3:25 Break Walter Sippel, FAA Billy Martin, NIAR 3:25 3:45 Inspection Challenges Rusty Jones, FAA 3:45 4:15 Substantiation of Bonded Repair Michael Borgman, Spirit Aerosystems 4:15 4:45 Moderated Discussions Mike Cann, FAA 4:45 5:00 Wrap Up and Closure Larry Ilcewicz, FAA 16

17 Challenge We have published expectations for initial certification of composite structure in AC B and other documents. The regulations are the same if it's type design or a modification to type design. Unless you are willing to discuss and propose different means of compliance to the regulations for modifications (including repairs), this new AC is going to look a lot like what is already published and you will all have this hurdle to meet. 17