C-17 Warning and Caution Computer

The Warning and Caution Computer (WACC) is part of the C-17 integrated overall Warning and Caution System (WACS) that accepts discrete data, and data from 1553B bus connected specialized peripheral Line Replaceable Units (LRUs). Data transmission within the system is accomplished with a dual redundant MIL-STD 1553B serial data bus. WACC processed data are distributed to the overhead Warning and Caution Panel (WAP) via the 1553B. In addition, the WACC provides direct outputs to drive other annunciator lamps in the cockpit. Included in the Warning and Caution System is the Central Aural Warning System (CAWS) which provides audio warning derived from a menu of stored messages. The CAWS is architecturally located on the Mission 2 bus. The connection to, and the formatting of data from the WACS 1553B bus to the Mission 2 bus, is accomplished via the 2 Aircraft/ Propulsion Data Management Computer (APM-2). The Warning and Caution System consists of two redundant WACCs. One WACC serves as the 1553B Bus Controller (BC) while the redundant WACC serves as the back up bus controller. To further enhance the WACS reliability, the redundant WACC is powered by a separate 28 Voltpower source.<>