Hi 

The Phase in date of the Parent part Revision is 11-28-2022

 In a setup like this the component parts in this structure must exit on or before this date, the existence is decided by the Phase in date of the Part Revision, when you add a component to a Structure we do not define the component revision, so system picks the earliest Phase in Date to validate if the part can be a component of the Structure, 

So if you change the Phase in date of the lowest revision of the Component Part in the Inventory Part/ Revision tab so that this new phase in data is earlier than or equal to 11-28-2022, you should be able to save the record,

If the component part you add here is a Subassembly with components, then you need to change the phase in date of all the components from bottom to the Top by modifying one at a time.

Other option is creating a new Revision of the Parent part FD-Fuel Tank so that the Phase in date of the new Revision is equal or greater than the Phase in date of the Component part that you try to add.