Context and Annex A

The first problem with DO-178C is that it is often poorly understood. This is often because the reader has not been able to understand the context in which it is set; that of aircraft certification. The second problem is that readers often want a quick guide to what they need to do and unfortunately they jump straight into the table at Annex A. The intent of these tables, written originally for DO-178B, was to provide a levelling of objectives.  In other words, which objectives would apply to which software Level, A, B, C or D.  The Annex gives a short title and the paragraph reference to the Objective.  If it applies at a particular software Level, there is a white dot, if it applies and an independent check is required, it is a black dot and, of course, if it does not apply, there is no dot.  To be clear, the objective is the reference text and not the wording in Annex A.  A common misunderstanding is that because there is a reference in Annex A to activities that these have to be done and are the only way to achieve the objectives; this is incorrect.  The activities are only included to provide some context and insight into the kind of evidence that might be provided for objective satisfaction.