Explanatory factors for the geographic distribution of U.S. civil aviation mortality

BACKGROUND: State-specific aviation-related mortality rates differ substantially between various geographical regions of the United States. PURPOSE: The purpose of this study was to ascertain important explanatory factors that account for the geographical distribution of mortality. METHODS: National Center for Health Statistics sources were used to calculate state-specific, age-adjusted mortality rates. Fatalities studied were those attributed to select civil aviation-related causes (ICD-9 E-codes 840.2-.6, 841.2-.6, 842.2-.6) that occurred from 1979-89. State-specific information on a variety of selected variables was obtained from census, commerce, and Federal Aviation Administration (FAA) sources. Multiple linear regression techniques were used to assess the relationship between selected variables and state-specific mortality rates. RESULTS: There were 13,048 deaths for a U.S. 11-year mean mortality rate of 4.9 deaths/1,000,000 general population. Mountainous states of the western U.S. had the highest 11-year mean mortality rates (range 8.6-79.6 deaths/1,000,000). Mid-Atlantic states had the lowest rates (range 1.6-2.9 deaths/1,000,000). Regression analysis identified pilot density (number of pilots per 1,000,000 general population), top elevation (highest point of land within state boundaries), and flight intensity (number of general aviation flight hours flown per pilot) as important factors in explaining 92% of state mortality differences. CONCLUSIONS: Highest aviation-related mortality rates are found in states with expanses of mountainous terrain, and relatively high pilot densities and flight activity levels.