Gantt Chart

sorry, trying to supply as much info as you need,
Basically if the line is down, there is no production, so production run (coloured bar) must extend until the run is completed during free time .
I've tried to display this graphically on this attachment,

I know this has changed a bit, but Ops Manager has informed me that engineers (required for change overs) will be working the same hours as operators so changeovers cannot take place whilst the entire plant is off.

I'm sorry if this is a bit blurred, but i'm not sure how to explain it.