Talk about swiss cheese though....
Aircraft dispatched with unserviceable TCAS (or TCAS failed at some point on EBO)
Aircraft requests climb in vicinity of other traffic
Climb request approved (obviously incorrectly)
By the time the climb commences after approval (or near enough to) crossing traffic is in the exact spot to cause a mid air....
Luckily TCAS was serviceable on one of the 330's!