.part03.rar indicates it is part of a multi-part archive ( .part01 , .part02 , etc.). All parts are required in the same folder to extract the content.
this file (and need help with the error "part 3 is missing" or similar)? Locate the other parts (1, 2, 4, etc.)? GF171122-C2R-FLT.part03.rar
You will need software like WinRAR or 7-Zip to extract the contents. Are you trying to: GF171122-C2R-FLT.part03.rar