Aircraft maintenance workers are exposed to high injury rates, but risk exposures are difficult to measure and task contributors are difficult to identify due to the wide variety of parts and irregularity of jobs in this industry. Subjective metrics, posture assessments, and lifting analyses were collected from 235 employees from five work areas in aviation maintenance, repair and overhaul (MRO) facilities to measure ergonomic risk factors and identify task factors contributing to poor biomechanics. Nordic Musculoskeletal Questionnaire indicated that the low back was the most commonly reported region of the body experiencing aches, pain, and discomfort (41% of participants), while knees were the highest (68%) in cabin maintenance, likely due to constraints in the aircraft cabin. Rapid Entire Body Assessment (REBA) assessments showed that 57% of the jobs examined fell within the high-risk category. Causes of poor biomechanics differed by work area, e.g., overhead work was a key contributor in the engine change facility, while non-adjustable workstations were a likely contributor in cabin maintenance and engine maintenance. The under-looked cabin maintenance, engine change, and logistic jobs are the most pressing work areas in MRO that need ergonomic interventions.