A phantom BOM is a BOM used for non-stocked subassemblies. In Microsoft Dynamics NAV, a phantom BOM is a production BOM that is chosen on a production BOM line.
A phantom BOM represents a group of items that are put together immediately before being used in production. Instead of listing each of the items needed in the production BOM lines, users can choose the phantom BOM. Phantom BOMs allow the MRP process to account for the components without having to create an Item card or a separate production order for the subassembly. The time required for assembling a phantom BOM is considered to be zero or is accounted for in the master item’s routing. Using phantom BOMs can also simplify the creation or review of production BOMs by listing the phantom BOM instead of each component. Deciding whether a subassembly will be set up as a phantom BOM or an item is a matter of opinion, and the decision is usually made by the engineers or production managers.