Horizontal Situation Indicator HSI Type AF/A24J-1, F4 Phantom II

The Type AF/A24J-1 Horizontal Situation Indicator, made by Collins Radio, was used in the iconic F4 Phantom II jet fighter of the US Air Force, Navy, and Marines during the Vietnam War.  In place of a conventional heading indicator, the HSI combines a heading indicator with a VHF omnidirectional range-instrument landing system (VOR-ILS)  display (see the description from the 1970 F-4C Flight Manual).  Our HSI traversed through the Sacramento Air Logistics center at McClellan Air Force Base in Nov 1977 (see label).