A radar warning receiver is an aircraft electronic device that detects and analyzes threat signals around the aircraft and alerts pilots to the analyzed threat signals to improve aircraft viability. Defective phenomena of radar warning receivers occur between aircraft operations such as power failure and boot errors. Consequently, there is a need to resolve radar warning receiver defects and improve quality. In this study, the cause of the defect phenomena was analyzed and improvement measures for each identified defect cause were presented. Process improvement was carried out to solve defects caused by the cause of occurrence, and process measures were added to strengthen product inspection procedures and prevent defects. The validity of design improvement was verified through the component and aircraft system flight test.