We're going to start testing a few raid encounters on all Beta servers this Sunday, October 17 at 13:00 PDT. Two encounters will be tested:
Omnitron Defense System in Blackwing Descent
Halfus Wyrmbreaker in The Bastion of Twilight
Blackwing Descent is a raid zone with an entrance located along the side of Blackrock Mountain.
The Bastion of Twilight's entrance is located within Twilight Highlands.
Since these are the beta realms, this schedule is subject to change at a moment's notice due to bugs and server issues. More raid tests will be occurring over the next few weeks.