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OSMA Releases Fastener Policy Update

OSMA Releases Fastener Policy Update

6-minute read
Close-up of various steel nuts and bolts

The Office of Safety and Mission Assurance (OSMA) simultaneously renumbered and published an update to NASA-STD-6008, NASA Fastener Procurement, Receiving Inspection, and Storage Practices for Spaceflight. The new document, NASA-STD-8739.14, NASA Fastener Procurement, Receiving Inspection, and Storage Practices for NASA Mission Hardware, is now available for download at standards.nasa.gov. This is the first substantive technical change to the document since its stewardship transferred from the NASA Office of Chief Engineer (OCE) to OSMA in 2008. The number change aligns with OSMA’s assigned number series for technical standards.

Now that NASA-STD-8739.14 is an OSMA technical standard rather than an OCE standard, it is not required to self-declare whether it is mandatory or not. Instead the title, forward and applicability statements align the document with OSMA’s new “accepted standard” approach to defining NASA Safety and Mission Assurance (SMA) policy. NASA Quality policy — NPR 8735.2C, Hardware Quality Assurance Program Requirements for Programs and Projects — when it is published later this year, will require programs and projects to use NASA-STD-8739.14 in their Quality Assurance (QA) Plans unless some other equivalent or risk-based alternative approach is applicable. (Read “OSMA Prepares to Release NASA-STD-8739.14 for Review” for information on that policy.) 

OSMA’s Mechanical Systems Assurance (MSA) project, who updated the policy on behalf of OSMA’s QA program, wrote the content so that the technical content can be used within or outside of a formal NASA Quality Assurance program; however, the applicability statements are tied closely to programs and projects managed in accordance with NPR 7120.5, NASA Space Flight Program and Project Management Requirements, or NPR 7120.8, NASA Research and Technology Program and Project Management Requirements. Programs’ and projects’ use of NASA-STD-8739.14, in whole or in part, will be determined by their Risk Management strategy and evaluation by relevant technical authorities (i.e., engineering Technical Authority and SMA Technical Authority). It should be noted that the scope of NASA-STD-8739.14 has elements of a Quality Management System (QMS) that are typically addressed globally by a NASA center or external supplier rather than on a project-by-project basis. Examples of these elements are counterfeit controls, incoming receiving inspection and storage controls that preserve lot traceability. NPR 8735.2C will require NASA center QMSs to reflect the relevant requirements found in NASA-STD-8739.14.

The update also expanded the title and applicability statements from an emphasis on spaceflight hardware to include any custom mission hardware integrated into an aircraft. This expanded scope is limited to fasteners used in instrument or experiment hardware that is outside of the purview of the Federal Aviation Administration certification processes and that can threaten aircraft safety or the safety of the aircraft crew (i.e., air worthiness).

Past interpretations of NASA-STD-6008’s use of the facture critical categories defined by NASA-STD-5019, Fracture Control Requirements for Spaceflight Hardware indicated that the standard was only for programs where fastener failure could cause a human safety catastrophe (i.e., significant injury or death). However, over the years, NASA-STD-6008 became widely used by programs and projects that benefited from a standardized acquisition, screening, qualification and materials control approach. The NASA-STD-8739.14 update continues to use criticality categories as a way of offering three different levels of QA: Level I, Level II and Level III. The standard no longer establishes the requirement to determine fracture criticality but instead assumes that that determination was already performed and, when NASA-STD-5019 is applicable, the fracture criticality is known. The NASA-STD-8739.14 QA levels are described in a manner that makes it readily apparent which QA level to use based on the known NASA-STD-5019 fracture criticality or which QA level to use when NASA-STD-5019 does not apply. In the latter case, the project has the authority to make the level selection that is compatible with the design and the project’s Risk Management approach. Because the standard requires different supplier selection criteria across the QA levels, it may not always be possible to associate a higher QA level with a fastener lot retroactively. Because the standard requires segregation of lots for even the lowest QA level, it will not be possible to assign a NASA-STD-8739.14 QA level to collections of fasteners whose lot traceability has been lost. This is a challenge for centers that would like to access large existing holdings of fasteners whose quality provenance does not fully align with a desired QA level. While the QA level definitions will assist projects that are using NASA-STD-5019 to choose the suitable QA level, in all cases, the decision-making about which QA level to use or whether to use fasteners that do not fully adhere to one of the QA levels is guided by the project’s Risk Management processes (e.g., risk assessment, QA Plan requirements, waivers, materials review boards, configuration and records management, and technical authority review). 

There will be different types of “users” of the document. These entities include the program or project that is levying the requirements (e.g., to use the standard and determining which QA levels are applicable), NASA in-house hardware developers, prime contractors, and prime contractors’ subtier suppliers (i.e., supply chain). Section 1 — which includes subsections titled Scope, Applicability, and Requirements Management and Flow Down — is addressed to the hardware acquirer (e.g., program or project, prime contractor). Section 4 is where the technical requirements begin. The entity who will procure and use the fastener, referred to as the hardware developer in the standard, executes the requirements, regardless of its place in the supply chain. 

The update reflects removed or changed technical requirements that create clarity and reduce duplication with other technical standards. The update also included the removal of requirements that prescribed how NASA materials engineers were to execute processes defined in NASA-STD-6016, Standard Materials and Processes Requirements for Spacecraft.

NASA-STD-8739.14 includes modified criteria and requirements for selecting a qualified or nonqualified supplier. Manufacturers or distributors are considered qualified if they are certified to one of the following QMS standards:

  • AS9100, Quality Management Systems – Requirements
  • ISO 9001, Quality Management System – Requirements
  • AS9120, Quality Management Systems – Requirements for Aviation, Space, and Defense Distributors

AS9003, Inspection and Test Quality Systems Requirements for Aviation, Space, and Defense Organizations is also allowed as an acceptable QMS standard when a third party has verified compliance. The suppliers associated with the products on the Defense Logistics Agency’s Qualified Supplier List for fasteners are now recognized as qualified. Reference to a NASA approved supplier list is no longer included because this list no longer exists. 

Language was simplified and clarified as it pertains to traceability, material test reports, and records delivery and retention. All of the incoming tests and inspections are summarized in a single table with columns dedicated to each QA level and whether the supplier is qualified or nonqualified. 

The standard provides clarifications for uses of quantitative, or semi-quantitative, chemical tests to avoid disagreements about the results of qualitative chemical tests. Hardness testing is no longer allowed as a substitute for tensile testing for fasteners whose small length puts them outside of the control limits set by the standard hardness test method. It is recognized that procurements through qualified suppliers, with complete traceability, resolves the tensile testing requirement for short fasteners.

Visual inspection magnification is now per the criteria contained in the applicable finish specification. Dimensional verification is required only for threaded fasteners and ASME B1.3, System 22 is required for QA Level I. System 22 or 21 can be used for QA Levels II and III.

Sample sizes for quality conformance tests are aligned with the ASTM F1470 standard. 

QA Level II fasteners now require complete traceability and procurement through a qualified supplier to preclude the requirement for destructive testing. When destructive testing is required, these sample quantities must be considered when placing orders for fasteners because they must be available for testing for each lot.

Questions regarding the understanding of the requirements in the standard can be directed to the technical Points of Contact: Brittany Kerr and Michael Viens.