Objectives: This study aimed to develop and test a comprehensive model analyzing direct and indirect relationships among workload, demographic factors, fatigue, work stress, and quality of life among aircraft maintenance personnel (AMP). Methods: This cross-sectional study was conducted at the maintenance, repair, and overhaul facility at Sultan Hasanuddin Airport, Makassar. Data collection combined structured interviews, standardized questionnaires (the NASA Task Load Index, Work Fatigue Feeling Measurement Questionnaire, Depression Anxiety Stress Scale-21, and World Health Organization Quality of Life-BREF), and objective measures (a Cocoro Meter for stress and an oximeter for physical workload). The model was examined using partial least squares structural equation modeling (PLS-SEM), which is well-suited to complex models with latent variables and non-normally distributed data. Results: In the PLS-SEM analysis, physical workload (β=0.229, p=0.018) and work experience (β=0.277, p=0.007) were significantly and directly associated with fatigue. Age significantly predicted work stress (β=0.371, p=0.001). Crucially, fatigue (β=−0.344, p=0.002) and work stress (β=−0.385, p<0.001) had significant negative direct effects on quality of life and were central mediators. No direct effects of exogenous variables on quality of life were observed. Cross-tabulation supported these findings; subgroups with higher physical demands, longer tenure, and older age reported greater fatigue, higher stress, and lower quality of life. Conclusions Fatigue and work stress are pivotal mediators that are significantly associated with reduced quality of life among AMP. Interventions to reduce physical workload and provide targeted support for more experienced and older workers may improve well-being and safety in the aviation maintenance industry.