qazme wrote on Apr 22^nd, 2024 at 2:09am:

From the C130 manual at AVIALOGS. BLUE LEFT-LOC : Flying inbound or outbound on the localizer beam. (Think LOC mode on Boeing/Airbus) GYRO PILOT : Used for any autopilot mode not using radios. Wings level, flies where you point it. Can use the trim and turn dials to fine tune during flight. RANGE LOC : Used for VOR/VORTAC tracking. AFF/APR : Approach mode - ILS loc and glideslope tracking. Not sure if this mode is working as intended.

avialogs dot com /aircraft-l/lockheed/item/4364-to-1c-130b-1-flight-manual-c-130b-and-sc-130b

Page 339 onward for anyone interested.