ARINC 777-2 PDF

Purpose and Scope

This document contains the physical form and fit dimensions, the electrical interface definition, and a description of the functions, operations, and interfaces of the Recorder Independent Power Supply (RIPS) for the Cockpit Voice Recorder (CVR) or crash survivable recorder units that combine voice with other recording functions. The RIPS is used to provide backup power for the recorder that is independent of the aircraft generated power busses. Attachment 1 shows a typical configuration.

The intention of such an arrangement is to allow the recorder to continue to record after primary power is lost. Since it is not practical to establish a protocol to distinguish between a routine power outage and all the possible scenarios of emergency power outage, the backup must be applied to all cases. For this reason, the duration of the backup must be limited to ensure that the recorder does not overwrite more of the oldest data than necessary.