Abstract
The purpose of the paper is to discuss methodology for software safety design in the field of civil aviation. RTCA DO-178B standard has been widely accepted in the civil aviation and the reality show that its effect in aviation safety is acceptable, while the method is considered not so safety oriented, although some safety concern has indirectly showed in DO-178B. The paper discusses current safety design mechanism for software certification compliance using DO-178B and system safety assessment methodology, and gives authority concerns if alternative means proposed.