A Manual of Flight-Test Procedure is an essential guide for conducting flight tests to ensure the safety and efficiency of aircraft. Published in December 1927 in the Engineering Research Bulletin No. 9, the manual is designed for both practitioners in the Air Services and industry specialists interested in flight testing. The manual outlines procedures for production testing and research testing of aircraft, emphasizing the importance of standard tests to determine performance metrics such as climbing and speed capacity. The authors provide detailed steps for preparing the airplane for flight, including weighing, installing, and calibrating instruments, and conducting various flight tests like the sawtooth climb and airspeed calibration. The manual stresses the significance of accurate data collection and reduction, utilizing recording instruments to minimize human error and ensuring precise measurements. It also discusses the importance of presenting the data comprehensively for general use and further research. The manual serves as a guide for improving design through research testing, evaluating new extremes of design, and developing tests for special performance aspects. It advocates for standardization in testing methods, instruments, and mathematical relations to achieve consistency and comparability in flight test results globally. This manual is vital for anyone involved in the field of aeronautical engineering, providing a structured approach to flight-testing procedures and contributing to advancements in aircraft design and performance evaluation.