Abstract: This paper describes the sources of measurement uncertainty related to flight testing, and analysis of some methods of eliminating or minimizing measurement uncertainty in collected flight data. Measurement uncertainty is an estimation of the potential error in a measurement result that is caused by variability in the equipment, the processes, the environment, and other sources. Flight testing is very complex experimental procedure. In fact, many of these error sources are and require special attention. As a result, it combines most of the types of errors found in experimental methods. For instance, systematic and random errors are found in the Data acquisition systems from which we collect our data. Random errors come from the atmosphere, electromagnetic interference and from pilot technique. Bearing in mind that the testing of the aircraft last stage of creating an aircraft, it is necessary to understand where the sources of the flight testing uncertainty lie, take steps to avoid or minimize that uncertainty, and then present the data in a manner that recognizes the remaining uncertainty. Evaluating the measurement uncertainty in any particular situation therefore comprises the identification, quantification and combination of these components. Therefore the Air Force Flight Test Centers is continually seeking ways to improve the planning, execution, analysis, and reporting of developmental test and evaluation programs. The statistical methods use to calculate confidence intervals or uncertainty for the final results.