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

extensive use of specialized inspection techniques and/or equipment. Intricate cleaning and substantial access or disassembly procedures may be required.

3.31 Integrity.

Integrity is comprised of the essential characteristics of systems and equipment which allows specified performance, safety, durability, reliability, and supportability to be achieved under specified operational conditions over a defined service lifetime.

3.32 Leak before burst.

A through crack in a fluid container will leak fluid before burst by demonstrating tolerance of a through thickness crack two times (2X) the wall thickness, or a size agreed upon with the Procuring Service, when subject to limit loading conditions.

3.33 Maintenance-free operating period.

This phase is that segment of the required operational service life during which no preventive maintenance is required to ensure performance and operational readiness. The results of durability testing and analysis are used to determine the maintenance-free operating period.

3.34 Maintenance Planning Data (MPD) Document.

To support maintenance of the type certificate for Commericial Derivative Aircraft (which indicates the airplane will be maintained in a condition of airworthiness equal to its certified or properly altered condition), the aircraft manufacturer/OEM provides a Maintenance Planning Data (MPD) Document to operators. The MPD includes both FAA mandatory requirements and OEM recommended (non-mandated) requirements. Mandated tasks are the Certification Maintenance Requirements (CMRs) and Airworthiness Limitations. Other tasks originate from the Maintenance Review Board (MRB) report (which includes tasks derived through MSG analysis or other FAA approved methodology), Service Actions, and other OEM information.

The MPD also addresses corrosion, structural fatigue/durability, and critical system/part reliability concerns

3.35 Maintenance Significant Item (MSI).

The term MSI is used in Maintenance Steering Group (MSG-3) Analysis and refers to parts whose failure could result in one of the following effects:

a. Impact to safety (ground or flight)

b. Be undetectable during operation (latent)

c. Impact ability to perform a mission d. Have significant economic impact.

3.36 Maintenance Steering Group - 3 (MSG-3) analysis.

This is a structed analysis, based on Reliability Centered Maintenance principles, which identifies appropriate preventative maintenance tasks to optimize aircraft availability versus maintenance cost. MSG-3 analysis is widely used in the commercial aviation industry.

3.37 Mission-critical component.

A mission-critical component is a component whose failure would: (a) prohibit the execution of a critical mission, (b) significantly reduce the operational mission capability, or (c) significantly increase the system vulnerability during a critical mission.