Stacked ECs
Stacked ECsEngineering Changes (ECs) may be "stacked" to revise parts that are not yet Released.
A part Revision may be in an EC that is not yet Released when new changes are required.
Stacking ECs may be useful when upcoming changes are urgent.
Once a part revision is locked down in the Approved state, it can be revised again.
The ECs must be Completed to Release the part revisions in order.
When an EC with a later revision reaches Review, if the previous part revision is not yet Released, an EC Dependency Route is created to block the later revision EC promotion.
To create stacked ECs for a part in the Approved state or higher:
Access a part Revisions page.
You may access the part Revisions page directly or click the part New Rev link on the EC Affected Items page of the EC that already includes the part.
Click 
on the part Revisions
page tool bar.
See Revise a Part for information on creating part revisions.
The new revision may be worked, and added to a new EC.
Specifications may not be PreReleased for the later revision until the earlier revision is Released.
A second part with a specification may not be promoted to Review and so the EC may not be promoted to Review until the earlier part is Released.