Maintenance performance assessment is important to be done because it is considered as one of the biggest costs in a company. Maintenance turns thing into its best performance so it is necessary to do maintenance. There are many tools to evaluate maintenance performance, one of them is Maintenance Scorecard. Combination between Six Sigma and Maintenance Scorecard can help evaluate maintenance performance with the calculation of DPMO and sigma level. Six Sigma Maintenance Scorecard has been proven to be an effective tool to evaluate maintenance performance according to previous research. Six Sigma Maintenance Scorecard used European Standard Maintenance Key Performance Indicators. There are 21 relevant indicators to the company, but only 9 were included in this research because of limitation. Results were measured using temporary Six Sigma Maintenance Scorecard in PT X Aircraft Services. It was still a temporary scorecard because there are some indicators that should be included too. Furthermore, this research also gives recommendation of aspects that should be improved and suggestions for both future research and PT X Aircraft Services.