The USAF 13th Fighter Squadron (13th FS The Panther Pack), formerly the 13th Tactical Fighter Squadron (13th TFS); is a USAF squadron based at Misawa Air Base in Northern Japan. The squadron was originally assigned to the 432nd FW with the F-16C/D Block 30 aircraft when it was assigned to Japan in 1987. In 1994, it was reassigned to the 35th FW and replaced its Block 30 aircraft with the Block 50. As a result, it then switched its tail code from MJ to WW in reference to its new SEAD capabilities.