Masters Theses

Date of Award

12-2000

Degree Type

Thesis

Degree Name

Master of Science

Major

Aviation Systems

Major Professor

Ralph D. Kimberlin

Committee Members

Frank Collins, C. T. N. Paludan

Abstract

U.S. Army UH-60 and OH-58 helicopter accident data was reviewed to determine injury mitigation effectiveness of a developmental cockpit airbag system The analysis methodology required that each accident file be completely reviewed to develop an understanding of injury mechanics and sequence. Pilot and copilot injury data and the associated injury producing mechanics were analyzed and injury mitigation envelopes considered. For the UH-60, the U S Army Safety Center accident database was reviewed via the Army Safety Management Information System (ASMIS) from 1 January 1985 to 31 December 1996 yielding 55 accident cases involving 59 aircraft. Forty-four accidents were classified as Class A and 11 were Class B. For the OH-58 the U.S. Army Safety Center accident database was reviewed via the ASMIS from 1 January 1980 to 31 March 1997, yielding 122 accidents involving 124 aircraft. Sixty-two accidents were classified Class A, 35 Class B and 25 Class C. For the UH-60 analysis, aircraft accident groups were: Fifteen catastrophic, four no strike injury, two unrelated injury, six deployment criteria not met and 32 potentially preventable injuries. For the OH-58 analysis, these groups were: Twenty-one catastrophic, 15 no strike injury, three unrelated injury, 23 deployment criteria not met, and 62 potentially preventable injuries. For the UH-60, the proposed analytical model predicted that CABS could have prevented one of three critical (33.3%), five of 15 (33.3%) major, 13 of 41 (31.7%) minor, and 15 of 25 (60%) minimal injuries. In addition, the analytical model predicted four of 15 (26.7%) major injuries mitigated to minor and 13 of 41 (31.7%) minor injuries mitigated to minimal. Overall, the analytical model predicted 34 (40.5%) of the 84 injuries could have been prevented and 17 (20.2%) reduced in severity. For the OH-58, the proposed analytical model predicted that CABS would have prevented one of 25 (4.2%) fatal and two of 29 (6.9%) critical injuries. The results also indicate that CABS could have prevented four of 99 (4%) of the major, 28 of 103 (27.2%) of the minor and 24 of 110 (20.8%) of the minimal injuries. Overall, of the 365 pilot injuries, 59 (16.2%) could have also been prevented and 36 reduced m severity (9.9%) This is a relatively small level of effectiveness compared to the UH-60. The large discrepancy is most likely due to the high number of lower extremity injuries caused by the lack of structural integrity in the OH-58, the high number of back injuries due to the aircraft's inability to withstand large vertical g-forces, and the significantly smaller UH-60 injury data population. In conclusion, it was shown that the airbag is predicted to be somewhat effective at preventing serious injuries, and very effective at preventing secondary injuries.

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