The two parts of the BOM are:
This is the first part of the document and it lists the assemblies that make up the vehicle, identified by a drawing number, the indication whether it is a Make or Buy assembly, and the corresponding diagram number.
The assembly list is given in C.I.G. (Assembly identification code) order.
Assemblies with different drawing numbers may share the same C.I.G., which therefore identifies a macro-assembly.
This document refers to the assemblies in the same order, breaking down the COMPOSITION OF ASSEMBLY into the elements that comprise it and the IEM number that appears on the reference diagram indicated in the list (if given).
An example of a BOM is given below.
It is possible to see the structure of the BOM and the contents.
Bill of materials example
