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

5.2.9 Component classification.

MECSIP components (components include all Line Replaceable Units [LRUs] and Weapons Replaceable Assemblies [WRAs]) shall be classified for criticality as safety-, mission-, durability- critical, durability non-critical or other/expendable components. The Failure Modes, Effects, and Criticality Analysis (FMECA) and the Hazard Analysis (HA) for each specific system shall be considered in the component classification process. Within the FMECA, it is the "end effect"

that should be considered for component criticality determination. Component classification shall be performed at the LRU and WRA level, if applicable. Criteria shall be established to

select and classify critical hardware components and determine an appropriate approach for

their design. The impact on safety-of-flight, mission completion, and production and maintenance costs shall be considered in the selection of critical components. The process detailed on figure 1 shall be used for the classification process. The MECSIP recognizes equivalency of parts classification per RCM and/or MSG-3, see below for correspondence of classification categories. Categories "a.", "b.", and "c." of the following component classification categories shall be used, as a minimum, when a Program is still in the development phase. If parts classification is accomplished when a Program is already in the sustainment phase, parts in categories "a." and "b." shall be defined:

	MECSIP CLASSIFICATION		RCM/MSG-3 CLASSIFICATION
a.	Safety-critical components	=	Evident Safety or Hidden Safety
b.	Mission-critical components	=	Evident Operational
c.	Durability-critical components
d.	Durability-noncritical components	=	Evident Ecomonic or Hidden Economic
e.	Other/expendable components.

The overall approach, analysis assumptions, and candidate component lists shall be documented in the MECSIP Master Plan.

NOTE: All emergency systems (e.g., Life Support, ejection, fuel dump, ram air turbine, emergency landing gear extention, fire extinguisher bottle squibs, etc.) are considered to have a flight-critical function. Components which are essential to maintaining the function of the emergency system shall be included in the Safety-critical list.