"There are two critical points in every aerial flight—its beginning and its end." — Alexander Graham Bell, 1906. From beginning till the end, the safety critical software plays a vital role in avionics and hence its development and its certification are indispensable. “RTCA DO-178B- Software Considerations in Airborne Systems and Equipment Certification” provides the normative guidelines to develop such systems. In particular, this standard provides the safety protocol and processes that should be followed to achieve safe systems. The safety guideline of DO178B emphasizes more on better documentation, communication and visibility into actual process. For realizing the guidelines of DO178B, a well-defined and collectively accepted (at least at the development team–level) interpretationof the protocol and processes is needed. To achieve such interpretation, a well-defined modeling language that models the process with safety construct is essential. The Object Management Group’s Software and System Process Engineering Metamodel SPEM 2.0 standard provides specification for modeling software and systems development processes. SPEM2.0, however, is a general purpose language and does notprovide sufficient coverage in terms of language constructs to address safety concerns. This thesis proposes S-SPEM, an extension of the SPEM2.0 to allow users to specify safety-oriented processes for the development of safety critical systems in the context of RTCA DO 178B. The DO178B is analyzed to capture the safety related process elements and SPEM 2.0 is extended to include those safety concepts. Moreover, to simulate and validate the modeled processes, S-SPEMconcepts are mapped onto XML Process Definition Language (XPDL) concepts and a transformation algorithm is sketched. Finally, a case-study will illustrate theusage and effectiveness of the proposed extension.