MIL-STD-1798 Mechanical Equipment And Subsystems Integrity ProgramThe purpose of this standard is to describe the general process to achieve and maintain the physical and functional integrity of the mechanical elements of aircraft systems. The goal of this integrity program is to achieve the desired level of safety and aircraft availability at the most economic cost across the life cycle of the weapon system. This standard allows the process to be tailored in a competitive environment to meet specific equipment, subsystem, and/or system requirements. The Mechanical Equipment and Subsystems Integrity Program MECSIP is implemented in the planning process and continued until retirement of the system.

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MIL-STD-1798C

thickness, or a size agreed upon with the Procuring Service, when subject to limit loading conditions.

5.3.2.7.6 Proof test analysis.

An analysis shall be accomplished to support the concept of proof testing. The analysis shall demonstrate that when the component is subjected to proof test conditions, the probably of undetected defects that would lead to failure is improbable per AWB-013 and

NAVAIRINST 5000.21B. Proof tests shall then be performed on each production component to effectively demonstrate that the component is damage tolerant.

5.3.2.8 Risk-based analyses.

When a design concept (reference 5.2.12.2) is utilized to minimize risk for safety-critical failures, a Hazard Risk Index (HRI) shall be computed in accordance with MIL-STD-882, AWB-013, and NAVAIRINST 5000.21B. MECSIP requires that the resultant risk of safety-critical failure must

be in the improbable range per AWB-013 and NAVAIRINST 5000.21B.

5.3.2.9 Vibration/dynamics/acoustic analyses.

Dynamics analyses shall be conducted to establish component vibration and acoustic mode shapes and frequencies. An analytical dynamic model of the system and/or critical components shall be developed to identify critical system modes, potential forcing functions, and resonance conditions. In addition, the analyses shall show that the vibration levels are acceptable for the reliable performance of equipment throughout the design service life requirements.

5.3.3 Development tests.

The amount and type of tests required to support the design and development will vary. These shall include, but not be limited to, the tests described in the following subparagraphs.

5.3.3.1 Material characterization tests.

Material characterization data such as strength, fatigue, fracture toughness, crack growth rate, corrosion resistance, wear, and thermal stability are required to support the design and to meet specific integrity-related requirements. When the data is not available, material properties shall be established by test. Test specimens shall be fabricated to include critical manufacturing processes (e.g., forming, joining, and assembly techniques). The test plan shall identify the vendor material characterization test requirements necessary to ensure minimum required properties in finished components throughout production.

Materials property data must be statistically significant. All materials shall be procured to existing materials and process specifications. Any changes to the materials and process specifications may require retest. Material properties should be placed under configuration control by the contractor. Section thickness, thermal treatments, and manufacturing methods shall be the same on the test hardware as the production hardware.

Existing data obtained from literature sources or previous Program experiences may be used. However, for safety- mission- and/or durability-critical component application (see 5.2.10), these properties shall be verified using specimens fabricated from actual parts, as required.

Materials for safety- and/or mission-critical systems and components (see 5.2.10) should be characterized to include the full range of design, operating conditions, and natural and induced environments. Cyclic loading and time-dependent properties should reflect the environmental and design usage defined in the contractual documents or as modified in this standard.