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No abstract

Technological advances have enabled components to be added to Helmet Mounted Displays (HMDs) that provide increased pilot capability. Future Air Force fighter aircraft are being developed to incorporate added technologies that could result in heavier and bulkier HMDs. The added weight and center of gravity changes to the pilot’s helmet ensemble from these additional components place the neck at an increased risk of injury during ejection. This paper outlines a preliminary research methodology studying the human neck response data from the Air Force Research Laboratory’s extensive human impact testing database using the Nij criteria as an evaluative tool. Initial results are presented.

New helmet mounted visually coupled systems (night vision devices and helmet mounted displays) which are designed to improve pilot performance may only increase the existing potential for neck injury during emergency escape due to the increase in head supported weight and altered center-of-gravity (CG). Designers need criteria for helmet system mass properties which will not increase the risk of injury above acceptable limits. A research study reviewed and analyzed accident statistics, current literature, and in-house laboratory data. Mass properties of various helmet systems were related to biodynamic responses of instrumented humans and manikins from impact tests conducted on the Armstrong Laboratory Vertical Deceleration Tower. Accident data revealed severe neck injuries are relatively rare in an operational setting. Laboratory studies of head/neck biodynamic response relating compression force at the occipital condyles to head supported weight indicate average forces exceed safe guidelines. The studies also suggest that helmet systems weighing less than 2.27 kg and having a center-of-gravity located only slightly above the anatomical axis origin of the head, will not induce severe neck injury during the catapult phase of ejection compared to current operational helmets.

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway. Suite 1204, Artington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MMM-YYYY) April 2004 TITLE AND SUBTITLE REPORT TYPE Final ReportPilot Harness Suspension Study AUTHOR(S)Benjamin C. Kuennen, John R. Buhrman DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTTest manikins are used extensively to collect ejection test data in situations not appropriate for humans, but the accuracy of the manikin data is directly dependent on how well the test set-up simulates the actual pre-ejection conditions experienced by the pilot. The objective of this program was to investigate the differences in harness tension among pilots and to compare these tensions to those typically used in a test manikin in order to provide validation for data collected during manikin impact tests. Four pilots and one Hybrid HI 50th percentile manikin were lifted off the ground with a suspension hoist where a series of harness tension measurements were taken. The results demonstrated large individual differences among the human subjects and between the humans and the test manikin in the amount of harness slack generated by the lifting. Recommendations were made for setting the harness side adjustment index at level three during future mankin tests. SUBJECT TERMSHarness suspension, Harness tension, Harness adjustment, PCU-15/P harness