FDR Analyzer Unit (FDAU) is an indigenous system to decode the double frequency coded data from Play Back Unit (UVS-3M) of Mi-171V helicopter. The FDR Analyzer Unit is provided with client software Planeview to analyze the FDR data. Flight Data Replay unit (FDRU) is an indigenous system equivalent to the Russian made Play Back Unit (UVS-3M) for MLP-23-1 type tape transport mechanism. The FDRU helps in downloading the data from the tape on to a PC with the help of FDAU (FDR Analyser Unit). The collected data is further processed in the client software Planeview for offline data analysis.