The development of aviation safety must be supported by reliable pilot competencies. One of the ways to realize the pilot competencies is by employing aircraft simulation. The objective of this research is to reduce the level of discrepancies in the King Air B200GT/350 I aircraft simulation by using the six sigma DMAIC method (Define, Measure, Analyze, Improvement, Control). Other tools for analyzing problems are Pareto diagrams, cause and effect diagrams, and FMEA. The discrepancies of aircraft simulation which become priority for improvement are the 47 percent discrepancies of the aircraft control system, the 30 percent discrepancies of modeling, and the 17 percent discrepancies of the cockpit I/O. The order of improvement priority is sorted from the highest RPN value at the repair stage. After the implementation of six sigma, the discrepancies  decreased from 45 percent to 18 percent, the sigma level increased from 2.42 to 3.04 and the cost of poor quality fell from IDR 64 million to IDR 28 million per month.