Not a C-130 problem, a C-12 compass problem on a CASA 212. I am a AF retiree working on an Army contract at Ft Bragg. Worked C-130 Comm/Nav and GAC for 19 years. We defined a problem with our C-12 compass system. Compasses are not synching. Still have a heading flag on the HSI when the needle is centered on the compass controller. At an aircraft heading of 0 degrees, the heading flag on the HSI does not go out until the controller is adjusted to 347 degrees. thank you in advance.