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

5.4.8 Component qualification.

Each MECSIP component shall demonstrate compliance to its requirements through a combination of the following: analysis; demonstration, inspection, similarity and/or test. Testing includes both component qualification test and component bench test. Examples of bench testing include: fuel pump pressure and flow; pump pressure pulses; actuator slew rate; sensor operation; electro-hydraulic servo valve operation; control stability/response; speeds; temperatures; amperes and voltages; and fault injection, detection, and accommodation.

5.4.9 Vibration and dynamic response.

All MECSIP safety-, mission- and durability-critical components shall be tested to verify they do not contain any damaging resonant conditions or responses within their operating range. Examples of these tests include: pump pressure pulses, resonance response searches, ping tests and dwells, and HCF endurance.

5.4.10 Strength testing.

Testing of components, assemblies, and/or systems shall be performed to verify strength requirements. Thermal and other environmental effects shall be simulated along with load applications when these conditions impose significant effects on the component strength. Examples of strength testing include proof, burst, and leak before burst testing. Test results shall be used to evaluate design margins and growth capability.

5.4.11 Durability testing.

For each component identified in 5.2.12 to have a maintenance free operating time, a test program shall be conducted to substantiate the overall durability of those components. Durability testing consists of component, assembly, and/or full system tests which simulate repeated loads and environmental conditions that represent design usage and design service life criteria. For components with periodic maintenance required to meet the installed life requirement, that maintenance shall be performed at the scheduled intervals during test.

Tests, particularly for expensive and long lead development items, shall be scheduled early in the test program to allow for identification and correction of critical areas and failure modes

(e.g., cracking, wear, chafing, leakage, etc.). The durability test schedule should be established

to support acquisition decisions which consider component criticality, risk mitigation, and lead time for all potential design issues during qualification. Testing milestones shall be established as part of the overall system test planning.

The results of durability testing shall be the basis for any design modifications, special inspections, and/or maintenance actions for critical components and installed systems.

Test duration requirements will vary depending on the specific application. Components shall be required to demonstrate a sufficient number (minimum two lifetimes) of design service lives to impart confidence that the component will achieve one lifetime in service. Test articles shall be selected which represent the production configurations. Test loadings and environments shall represent the significant elements of the design service usage spectrum. Test loadings shall be combined with environmental degraders, where appropriate, to simulate actual usage (e.g., cycles with dust immersion). Truncation and simplification of the repeated loads and environments shall be substantiated by analysis and/or test to verify equivalency to the design usage spectrum.