The controller issued a traffic call to the helo about the CRJ but failed to issue a traffic call to the CRJ advising him of the helo, its position and intentions which is not only required by FAA7110.65 but it let’s the CRJ know to be looking for the aircraft. There are specific rules and phraseology for approving “Visual Separation” that must be issued to both aircraft and this was not done.
When a CA (Conflict Alert) goes off there is a loud audible alarm in the tower cab and the two conflicting data tags will both flash on the radar to alert the controller that immediate action is needed. “Pass behind” is not a positive control instruction and an immediate instruction such as “PAT25 turn left immediately traffic less than a mile is a CRJ landing RWY 33” as you don’t just assume or hope they are going to miss.
There are errors on ATC side and errors on the helo pilots side and unfortunately 67 people paid the price for these mistakes.
