We have selected the study of software development life cycle- waterfall model, herein after is referred to as SDLC for brevity purpose. We have been allowed to study in the software firm - Aviation Management Consultants. The researchers studied the software named –“Routonomics” developed by the firm. The software enables the airlines to prepare the business plan with 5 years perspective. The purpose of selection of this subject is that SDLC- Waterfall Model is the reference model of any software related work. Many SDLC models evolved from this basic concept. Further, the firm introduced a small change in one of the reports to enable us to understand the practical perception of the SDLC. The researchers were involved in the simulated development of small change in the report.