The Rockwell Collins AHC-85E is an Attitude Heading Computer that is part of the AHS-85E Attitude Heading System. The AHC-85E Attitude heading computer has one low-speed ARINC 429 receiver, initialization timer, three high-speed ARINC 429 outputs, discrete initialization annunciator output, motion monitors, reduced drift rate over temperature variations while in DG mode, box orientation test and four modes of STIM and AHC-85E orientation available in STIM mode. The AHC-85E does not support analog interface to flight control systems. The AHC-85E may operate from aircraft +28-V dc battery bus for approximately 11 minutes after shutdown of primary 28-V bus.
The AHC-85E is housed in an ATR, short, full height case measuring 4.875 inches wide, 14.50 inches deep, 7.63 inches high and weighs 14.20 pounds not including the mounting rack. The AHC-85E is rack mounted in a UMT-16( ). The AHC-85E operates at a maximum altitude of +55,000 feet with an operational temperature range of 55 to +70°C.