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

5.2.14  Maintenance concepts.

The operational service life requirements may be satisfied by a designed-in, maintenance-free operating period and scheduled preventive maintenance. In early trade studies, the contractor shall evaluate the impact of maintenance-free versus scheduled maintenance operating periods on cost, weight, performance, aircraft availability, and potential for maintenance-induced damage.  The studies shall also consider the logistics and support requirements, the overall maintenance concept, and the implementation approach for component/system maintenance tracking. The tracking system must assist the MECSIP Manager in performing the duties listed

in Task V.  The result of these trade studies will be used to define the design service life criteria for specific components as well as in-service maintenance required to achieve the specified

total required operational service life. Establishment of designed-in scheduled preventive

maintenance must be consistent with the operational, logistics, and support requirements. The approach to definition and development of equipment maintenance concepts shall be included

in the MECSIP Master Plan.

5.2.15   Electrical Wiring Interconnect System (EWIS) Design Actions, Task One.  (See

EWIS MIL-HDBK-525 for more details.)

Document overall EWIS and identify critical circuit paths and functions (AS50881, AC 25-27A, AC 25.1701-1, and AC 25.1309-1A)

a.   Identify EWIS components and materials and all power and signal paths and conduct a functional hazard analysis;

b.   Document wiring configuration and circuit schematics and functions;

c.   Document physical wire routing throughout the aircraft;

d.   Conduct an aircraft functional hazard analysis of EWIS failure modes, effects and criticality analysis (FMECA) (AC 25.1701-1);

e.   Document EWIS components and characteristics such as installation and separation;

f.    Identify catastrophic failure modes and mechanisms in critical EWIS components; and g.   Identify physical failures of the EWIS that can cause damage to co-located EWIS or

surrounding systems, structural elements, or injury to personnel.

5.2.16  Product Integrity Control Plan.

The contractor shall implement special controls to ensure the required integrity characteristics of safety-critical parts throughout production and sustainment is achieved/maintained.   Additional candidates for specialized controls are parts classified as mission-critical, durability-critical, and items which have hidden failure modes.  Specialized controls may be required for materials, processes, manufacturing, quality, nondestructive inspection, corrosion prevention, etc.  The Product Integrity Control Plan shall be a living document.  The initial version will be submitted in Task II, and updated in each successive MECSIP Task. As a minimum, the Product Integrity Control  Plan shall include:

a.   The critical parts list and selection rationale;

b.   Basic material properties, allowables, and process data used in the analyses and trade studies;

c.   Procedures to identify special provisions on the part drawings;

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