OOSC, Part II, Item 3. Coupling Devices, b. Upper Coupler - Flathead Countersunk Socket Head Caps

During a recent inspection it was discovered that the upper coupler bolts on a MC-331 cargo tank had several loose bolts. A total of 10/12 bolts on the left side and 11/12 bolts on the right side were loose. The upper coupler was secured using flat countersunk socket head cap screws. When using the OOSC it references the bolt table for the number of effective bolts per side and a Note: This only applies to hex head bolts and should not be applied to flat countersunk socket head cap screws. Is there a total number of effective flat head socket cap screws per side that would be required before it is considered an imminent hazard for a MC331 carrying a hazardous material? We do not believe that loose bolts would be considered effective. Second issue request/same topic

Please address the issue to include flat head socket cap screws in the OOSC and indicate the appropriate action an inspector should take depending on the number of ‘effective” screws. Currently, if all or several flat head socket cap screws are loose and no longer “effective” then based on the current OOSC it is not an OOS.

Request to revisit issue # 17-010-VEH and add verbiage to Part II, Item 3, Coupling Devices, b.(4)-Upper Coupler Bolts. Changes to include flat countersunk socket head cap screws in the Bolt Table, remove the note or add verbiage similar to: “For any bolt not specified in the table below by type and size when more than 25% of the fasteners are loose” it would be OOS. This would match the support and anchor requirements for Cargo Tanks. Currently, if all or several flat head socket cap screws are loose and no longer “effective” then based on the current OOSC it is not an OOS.