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.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 - 26 - 27 - 28 - 29 - 30 - 31 - 32 - 33 - 34 - 35 - 36 - 37 - 38 - 39 - 40 - 41 - 42 - 43 - 44 - 45 - 46 - 47 - 48 - 49 - 50 - 51 - 52 - 53 - 54 - 55 - 56 - 57 - 58 - 59 - 60 - 61 - 62 - 63 - 64 - 65 - 66 - 67 - 68 - 69 - 70 - 71 - 72 - 73 - 74 - 75 - 76 - 77 - 78 - 79 - 80 - 81 - 82 - 83 - 84 - 85 - 86 - 87 - 88 - 89 - 90 - 91 - 92 - 93 - 94 - 95 - 96 - 97

MIL-STD-1798C

All test results shall be evaluated and compared against the original analytical predictions for wear and life. When damage is worse than predicted, the affected components shall be re- analyzed and appropriate corrective actions taken.

5.4.12 Vibration/dynamics/acoustics tests.

These tests shall be conducted to verify the vibration, dynamics, and acoustics response characteristics of the installed system and/or critical system components. These tests shall account for aircraft equipment installation dynamic transmissibility.

5.4.13 Damage tolerance tests.

Damage tolerance tests should be performed when deemed appropriate for specific applications. These tests shall be conducted to verify the damage tolerance characteristics of safety-critical and mission-critical components. These tests are used to establish damage tolerance margins, crack growth rates, critical crack lengths, residual strength, fail safety, leak before burst, or other characteristics defined by the specific damage tolerance criteria. No testing will be necessary for relatively-simple geometries and well-characterized materials, if there is adequate confidence in the accuracy of the analysis. Coupon, element, or component-

level testing shall be necessary for all other cases. The combination of test and analysis shall be adequate to impart confidence that the component will achieve one lifetime of service. An in-

service inspection period shall be established at one-half the validated design service life.

Components which satisfy damage tolerance through high durability margins shall be tested to the appropriate number of equivalent lives (the number of lifetimes analyzed/tested is a function

of the material used-typical values used for damage tolerance evaluation are four lifetimes via

analysis with testing to demonstrate two lifetimes) necessary to gain high confidence that the component will achieve one lifetime of service.

5.4.14 Thermal, environment, and loads survey.

Temperatures, loads, and other environmental factors shall be measured during the component development and system functional and flight tests. These values shall be compared against predicted values to verify design criteria. Data obtained from these surveys will be used to adjust operational limits and maintenance actions as determined from analysis and tests. The information will also be retained as "lessons learned" to assist in the development of criteria for future applications. The plan and approach for conducting this survey shall be included with the MECSIP Master Plan.

5.4.15 Overspeed/overtemperature tests of rotating parts.

Overspeed and overtemperature tests shall be conducted to substantiate/correlate analytical predictions. For the overspeed test, all rotors should be subjected to equipment operation for a stabilized period of at least five minutes duration at the required margin over maximum allowable steady-state speed at the equipment's maximum allowable temperature.

Following the test, parts and assemblies should be within allowable dimensional limits and there should be no evidence of imminent failure. Upon successful completion of the overspeed test, the same equipment shall be operated at the required temperature over the maximum allowable temperature and at no less than maximum allowable steady-state speed for five minutes. Following the test, parts and assemblies should be within allowable dimensional limits and there should be no evidence of imminent failure.