The primary objective of this study was to establish maximum human voluntary static tolerance levels of neck compressive loading to ensure the safe operation of a proposed Joint Strike Fighter (JSF) Head/Neck Restraint System (HNRS). A laboratory helmet-load apparatus was designed and used to safely apply compressive forces to the head/neck of 46 subjects’ (26 female;​ 20 male). Nearly all subjects were able to sustain maximum forces of at least 120 lbs for 5 seconds, with several subjects tolerating maximum sustained forces of over 200 lbs. Neck circumference was the most significant variable across gender with larger neck circumferences correlating to higher sustained forces. Regression models, however, demonstrated low R² values due to high maximum voluntary load variability among subjects of similar weights. Such findings suggest that while compressive neck forces of 100 lbs could be safely tolerated by potential users of the HNRS, no single force setting will likely be ideal for all users.