Ouch! Bad Timing To Cancel So Many Flights

I believe PSA is Wholly Owned, so they would have been doing regional somewhere. As to their Maintenance, I am sure it is a combination of In House Maintenance and Contracted MX. Now who would have completed this AD, I won't speculate since I don't work with this type of aircraft so I have no idea what the time frame for accomplishment is. From what I have heard, this is only pertaining to PSA aircraft.
 
That's the down Side to farming out.

Yes. The downtime will be costly as well as all the reinspects with possible unlimited O/T to get it done in timely manner.