On Independence Day, the warship got underway for her second tour of duty off Vietnam. After a week on the northern SAR station, she relieved "Sterett" again on 13 July, but this time as PIRAZ ship. On the night of 19 July, five MiGs attacked "Biddle" in two raids. In the first raid, the guided-missile frigate's Terrier missiles destroyed one of the intruders. She claimed a possible kill in the second raid and credited it to her gun batteries. The warship drove off the remaining attackers and suffered no damage herself.