Military Maintenance Working Hours?

In Naval Aviation the only ones with mandatory crew rest guidelines were the Aircrew. However, the Squadron would set limits sometimes like make us go home after 18hrs or so because of safety issues. These Squadron Level instructions or SOP's usually weren't put in place until somebody got hurt or in an accident on the way home and fatigue was found to be a factor. They say that most safety instructions are "written in blood" for a reason...