Army aeromedical crash rates.
BACKGROUND
Safety is a principal concern for everyone in aviation, including those in military and civilian aeromedical programs. The U.S. Army flies thousands of helicopter missions each year, including many aeromedical flights. The comparison between Army general and aeromedical aviation crash data provides a benchmark for establishing patterns in aeromedical safety and may be useful for similar programs examining safety profiles.


OBJECTIVE
To determine the crash rates of Army aeromedical rotary-wing (helicopter) programs and compare them with crash rates in Army general aviation.


METHODS
Retrospective review of safety data from 1987 to 1995. Crashes or mishaps are categorized into three classes: A, B, and C. Class A reflects the most serious mishap and involves loss of life or aircraft destruction, whereas classes B and C represent lesser but still significant mishaps. Crash rates are compared on a year-by-year basis and are reported as events per 100,000 flight hours. Statistical analysis was performed by the z test with Yates' correction, with significance set at p < or = 0.05.


RESULTS
During the study period, 13.31 million total flight hours were recorded, with 741,000 aeromedical hours logged. The mean Army general aviation class A crash rate was 1.86 compared with the aeromedical rate of 2.02. The mean general class A to C crash rate was 7.37 compared with the aeromedical rate of 7.44. Between 1992 and 1995, there were 3 years when the Army aeromedical program suffered no class A mishaps. Differences between study groups are statistically significant, but they are interpreted conservatively given the very low incidence of mishaps in both groups. Both rates are comparable with published civilian mishap rates.


CONCLUSIONS
There is a very low overall incidence of crashes in both groups. There may be no practical difference between Army general and aeromedical aviation mishap rates. Furthermore, Army crash rates are comparable with published civilian mishap rates.
De Lorenzo
R A
RA
Department of Medical Science, U.S. Army Academy of Health Sciences, Fort Sam Houston, TX 78234-6132, USA.
Freid
R L
RL
Villarin
A R
AR
D000060:Accidents, Aviation / Q000706:statistics & numerical data* / Q000639:trends; D017732:Air Ambulances / Q000706:statistics & numerical data*; D000401:Aircraft / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008889:Military Personnel; D011159:Population Surveillance; D012189:Retrospective Studies; D012449:Safety; D014481:United States / Q000453:epidemiology