At Boeing's South Carolina Dreamliner plant, the International Association of Machinists carved out a 178 member unit of mechanics - flight line readiness techs and inspectors - and hoped that the Speciality Healthcare micro-union strategy would prevail. Unfortunately for the IAM, the board had already reverted to the standard of community-of-interest test (in the PCC Structurals, Inc. 2017 decision). The board noted that the mechanics did not share an internal community of interest and did not have sufficiently distinct interests from those employees excluded from the petitioned-for unit (the remaining 2500+ employees).

Here's the official board decision.