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Philosophy and Assumptions |
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Philosophy and Assumptions |
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Philosophy and Assumptions
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Philosophy and Assumptions |
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Philosophy and Assumptions |
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RAM Commander assumes that all corrective action consists of the following maintenance tasks:
| • | Preparation |
| • | Fault isolation |
| • | Disassembly |
| • | Interchange (Remove/Replace) |
| • | Reassembly |
| • | Alignment (Calibration) |
| • | Checkout (Verification) |
| • | Start-up |
| • | Other (all other tasks not in the above list) |
In addition to the general assumptions listed in MIL-HDBK-472 Procedure 5, the RAM Commander maintainability prediction process includes an additional term: level of replace. Level of replace represents the specific maintenance level (location) where an item is to be removed and replaced. Therefore, the level of replace of an item corresponds to the level of repair of its parent. This assumes that an assembly is repaired by replacing one or more of its lower level parts.
The level of replace of the lower level parts must be equal to the level of repair of the assembly. MTTR can only be calculated for this situation:
When there are functional items in the product tree, then use “level of replace = unapplicable” so that these items will be transparent for MTTR calculation purposes. Unapplicable may be assigned to as many levels as required:
