A modification is a generic definition of high-level definitions of service bulletins, airworthiness directives and other sundry change or maintenance request definitions for an engine type (or a top-level part). A modification on a part might actually require different work activities and/or spare parts be used on the part, or on its components. The components that are impacted by a modification (because work is performed on them) are called affected parts. For example, a modification on a jet engine might require that work be done on the three main rotor hubs of the Fan Module subassembly. The modification is defined as being on the jet engine, with affected parts being the rotor hubs that are actually two or three levels down in the overall jet engine structure.
A modification might be defined with a comply and a 
de-comply definition; the comply definition would describe how to perform the 
modification while the de-comply would describe how to back out of the 
modification after it was successfully performed.
Within IFS/Complex Assembly MRO, the handling of these modifications during an engine visit 
would be handled through a series of repair shop orders generated during the 
Disposition process. As parts are inspected during the Disposition process, the 
inspector will also be noting any modifications in which the part being 
inspected would be an affected part, and the inspector would be marking the part 
to be handled for the modification. This would cause the Disposition process to 
look at the modification definition in IFS Manufacturing to find the allocations 
and/or operations needed to perform the modification on the affected part being dispositioned.
Because the data to create allocations and operations is not present in 
IFS/Vehicle Information Management and 
would only be used by shop orders, the intent is to take the modification 
information in IFS/Vehicle Information Management and transfer it into IFS Manufacturing, so that 
repair codes can 
be associated to point out the allocations and operations needed to do the work. 
This will require that application is able to identify modifications in 
IFS/Vehicle Information Management that 
are ready for transfer, is able to assign one or more modifications to one or 
more sites, and transfer the modification and affected part information into the 
site or sites selected. 
Once this is done, information and link of repair codes to the modifications and 
affected parts transferred into manufacturing is available. System would allow 
to  re-transfer VIM modification data into Manufacturing, to handle situations 
where a modification has been created in IFS/Vehicle Information Management after the original transfer, or to 
deal with changes to the definition of the modification after the transfer was 
made.