Applying Software Safety Methodologies to the SH-2G(A) Glass Cockpit

The SH-2G(A) maritime helicopter, developed by Kaman Aerospace Corporation for the Royal Australian Navy (RAN), incorporates a ‘glass cockpit’ to provide the crew interface for display, command and control of aircraft equipment, avionics, sensors and weapons. Kaman applied system safety methodologies for ensuring that software safety critical functions for data processing and display were identified and treated per the software risk index defined in MIL-STD-882C. The analysis technique includes developing specific prerequisite safety ‘products’ that serve as the basis for subsequent analysis and provides the framework and the context for understanding system-level hazards, functional contributions, failure modes to those hazards, and determination of the safety critical functions for the software builds. By defining aircraft system-level hazards and conducting a Functional Hazard Analysis, the safety critical functions were determined. This served as the basis for performing a software causal factor analysis. The output of this analysis is hazard-level fault trees and safety-specific software requirements for hazard elimination, mitigation, or control. In addition, this analysis identified existing hazard mitigation that was designed into the system through the implementation of sound engineering principles.