MIL-HDBK-17-3F Volume 3,Chapter 8 Supportability CHAPTER 8 SUPPORTABILITY 8.1 INTRODUCTION Supportability is an integral part of the design process that ensures support requirements are incorpo- rated in the design and logistics resources are defined to support the system during its operating or useful life.Support resource requirements include the skills,tools,equipment,facilities,spares,techniques, documentation,data,materials,and analysis required to ensure that a composite component maintains structural integrity over its intended lifetime.When the load carrying capability of an aircraft,or product is compromised,(i.e..loss of design function),the damaged structure must be restored quickly and at low cost.Customer requirements can dictate maintenance philosophy,materials availability,and repair capa- bilities that a design team must incorporate throughout the design process.As the contributors to this chapter were primarily from the aircraft industry,the text is slanted towards its particular needs.However, the guiding principles can be beneficial in other composite applications. Since the operating and support cost of a vehicle continues to escalate throughout its life,it becomes imperative to select and optimize those designs that maximize supportability.Life cycle cost,being com- prised of research and development,acquisition,operational and support,and disposal costs,is often a crucial customer requirement for any new weapon system or commercial transport.Often,design changes that enhance producibility,improve vehicle availability,and reduce operational and support costs,far outweigh the short-term increases in acquisition costs.Lost airline profits and reduced wartime readiness are a direct result of designs that did not incorporate supportability early in the design process. Telltale indicators of non-supportable designs include expensive spares,excessive repair times,and un- needed inspections. Aircraft users are often constrained to perform maintenance during aircraft turnaround,after each day's usage,and during scheduled maintenance.Repair time limitations can range from several minutes to several days.In each case users of aircraft containing composite components require durable struc- tures that,when damaged,can be repaired within the available support infrastructure including skills,ma- terials,equipment,and technical data. Composite designs are usually tailored to maximize performance by defining application dependent materials,ply orientation,stiffening concepts,and attachment mechanisms.High performance designs are often less supportable due to increased strain levels,fewer redundant load paths,and a mix of highly tailored materials and geometries.Product design teams should focus on a variety of features that im- prove supportability including compatibility of available repair materials with those used on the parent structure,available equipment and skill,improving subsystem accessibility,and extended shelf-life com- posite repair materials.Structural elements and materials should be selected that are impervious to in- herent and induced damage especially delaminations,low velocity impacts,and hail damage.Each sup- portability enhancement feature results from the designer having an explicit knowledge of the aircraft's operational and maintenance environment and associated requirements and characteristics.Other de- sign considerations also have an impact on supportability including durability,reliability,damage toler- ance,and survivability.A supportable design integrates all the requirements,criteria,and features neces- sary to provide highly valued products in terms of performance,affordability and availability. This section is designed to assist integrated product teams in the development of supportable prod- ucts through five basic sections:1)Introduction-which provides an overview of the Supportability chap- ter;2)Design for Supportability-which provides the designer with design criteria,guidelines and check- lists to ensure a supportable design;3)Support Implementation-which defines and demonstrates those key elements of supportability that must be performed to insure mission success;4)Composite Repairs of Metal Structure-which provides an alternative means to standard metal repair options,and(5)Logistics Requirements-which establishes the support resources needed to maintain the backbone of the support structure.Each section provides the designer and aircraft user with the supportability data and lessons learned that will reduce cost of ownership and improve aircraft availability.Other sections throughout MIL-HDBK-17 discuss the details needed to design supportable components.Sections contained in Vol- 8-1MIL-HDBK-17-3F Volume 3, Chapter 8 Supportability 8-1 CHAPTER 8 SUPPORTABILITY 8.1 INTRODUCTION Supportability is an integral part of the design process that ensures support requirements are incorpo￾rated in the design and logistics resources are defined to support the system during its operating or useful life. Support resource requirements include the skills, tools, equipment, facilities, spares, techniques, documentation, data, materials, and analysis required to ensure that a composite component maintains structural integrity over its intended lifetime. When the load carrying capability of an aircraft, or product is compromised, (i.e., loss of design function), the damaged structure must be restored quickly and at low cost. Customer requirements can dictate maintenance philosophy, materials availability, and repair capa￾bilities that a design team must incorporate throughout the design process. As the contributors to this chapter were primarily from the aircraft industry, the text is slanted towards its particular needs. However, the guiding principles can be beneficial in other composite applications. Since the operating and support cost of a vehicle continues to escalate throughout its life, it becomes imperative to select and optimize those designs that maximize supportability. Life cycle cost, being com￾prised of research and development, acquisition, operational and support, and disposal costs, is often a crucial customer requirement for any new weapon system or commercial transport. Often, design changes that enhance producibility, improve vehicle availability, and reduce operational and support costs, far outweigh the short-term increases in acquisition costs. Lost airline profits and reduced wartime readiness are a direct result of designs that did not incorporate supportability early in the design process. Telltale indicators of non-supportable designs include expensive spares, excessive repair times, and un￾needed inspections. Aircraft users are often constrained to perform maintenance during aircraft turnaround, after each day’s usage, and during scheduled maintenance. Repair time limitations can range from several minutes to several days. In each case users of aircraft containing composite components require durable struc￾tures that, when damaged, can be repaired within the available support infrastructure including skills, ma￾terials, equipment, and technical data. Composite designs are usually tailored to maximize performance by defining application dependent materials, ply orientation, stiffening concepts, and attachment mechanisms. High performance designs are often less supportable due to increased strain levels, fewer redundant load paths, and a mix of highly tailored materials and geometries. Product design teams should focus on a variety of features that im￾prove supportability including compatibility of available repair materials with those used on the parent structure, available equipment and skill, improving subsystem accessibility, and extended shelf-life com￾posite repair materials. Structural elements and materials should be selected that are impervious to in￾herent and induced damage especially delaminations, low velocity impacts, and hail damage. Each sup￾portability enhancement feature results from the designer having an explicit knowledge of the aircraft's operational and maintenance environment and associated requirements and characteristics. Other de￾sign considerations also have an impact on supportability including durability, reliability, damage toler￾ance, and survivability. A supportable design integrates all the requirements, criteria, and features neces￾sary to provide highly valued products in terms of performance, affordability and availability. This section is designed to assist integrated product teams in the development of supportable prod￾ucts through five basic sections: 1) Introduction - which provides an overview of the Supportability chap￾ter; 2) Design for Supportability - which provides the designer with design criteria, guidelines and check￾lists to ensure a supportable design; 3) Support Implementation - which defines and demonstrates those key elements of supportability that must be performed to insure mission success; 4) Composite Repairs of Metal Structure – which provides an alternative means to standard metal repair options, and (5) Logistics Requirements - which establishes the support resources needed to maintain the backbone of the support structure. Each section provides the designer and aircraft user with the supportability data and lessons learned that will reduce cost of ownership and improve aircraft availability. Other sections throughout MIL-HDBK-17 discuss the details needed to design supportable components. Sections contained in Vol-