SSI Selection Questions

The MGS-3 guideline for aircraft structural analysis describes several criteria to identify a structural significant item (SSI). It says:

"A Structural Significant Item (SSI) is any detail, element or assembly, which contributes significantly to carrying flight, ground, pressure or control loads, and whose failure could affect the structural integrity necessary for the safety of the aircraft."

In MPC, these items are identified in the structural hierarchy with the following icon:

A structural item will be marked as an SSI if you answer "Yes" to any of the SSI selection questions displayed in the bottom panel of the Structural Item Properties tab, as shown next:

Although the answers to these questions are displayed for all levels in the structural hierarchy, they can only be answered at the lowest (structural item) level. The answers displayed at higher levels show the combined responses from all the structural items in that branch of the hierarchy.