The IPC Reference forms part of the Logistic Support Analysis (LSA)
data, and is used as a reference if you do not know what a component
is or what it looks like.
If the maintained parent number is a Maintenance Significant Item
(MSI), the manufacturer may supply an Illustrated Parts Catalogue
(IPC).
The purpose of this field is to reference the product structure linked
to the IPC, for example, quoting the IPC number, page number, or the
paragraph i.e. it shows the part in its "where used" application.
It is an optional text field with a maximum length of 20 characters.