The Rockwell Collins AHC-85 is an Attitude Heading Computer that is part of the AHS-85 Attitude Heading System. The AHC-85 Attitude heading computer has one low-speed CSDB receiver, initialization timer, three high-speed CSDB outputs, discrete initialization annunciator output, motion monitors, box orientation test and four modes of STIM and AHC-85 orientation available in STIM mode. The AHC-85 supports analog interface to flight control systems. The AHC-85 may operate from aircraft +28-V dc battery bus for approximately 11 minutes after shutdown of primary 28-V bus.

The AHC-85 is housed in an ATR, short, full height case measuring 4.875 inches wide, 14.50 inches deep, 7.63 inches high and weighs 14.00 pounds not including the mounting rack. The AHC-85 is rack mounted in a UMT-16( ). The AHC-85 operates at a maximum altitude of +55,000 feet with an operational temperature range of 55 to +70°C.