Work-related aviation fatalities - Alaska, 1990-1994

Morbidity and Mortality Weekly Report, June 6, 1997

During 1990-1994, the annual occupational fatality rate in Alaska was 29.1 deaths per 100,000 workers, nearly six times the annual rate for the United States (5.1 per 100,000). In the United States, aviation-related fatality is the seventh leading cause of fatal occupational injury (1); however, in Alaska, this category is the second leading cause of occupational death. To characterize occupational aviation fatalities in Alaska, CDC analyzed all fatal occupational aviation crashes in Alaska during 1990-1994 (the most recent year for which complete data were available) and compared findings with overall patterns for the United States. This report summarizes the results of that study, which indicate that workers in Alaska are at increased risk for being killed in aircraft crashes when compared with all U.S. workers.

For all aircraft crashes during the study period, National Transportation Safety Board (NTSB) Accident Briefs were abstracted to obtain information about flight purpose, weather, aircraft, pilot, and probable cause. These reports were merged with records from the Alaska Occupational Injury Surveillance System, a database established and maintained by CDC's National Institute for Occupational Safety and Health, which includes information about cause of death, occupation of decedent, and circumstances associated with the crash. This study includes all occupational deaths related to commercial, military, and general aviation (i.e., all flying not involving military aircraft, scheduled airlines, and commuter or air-taxi service). For this analysis, an aircraft crash was defined as an incident in Alaska in which an aircraft in motion sustained substantial damage or an incident that resulted in injury or death to an aircraft occupant. An aircraft crash was categorized as occupational if at least one of the occupants in the aircraft was 1) working for pay or compensation; 2) working as a volunteer emergency medical technician, firefighter, or law enforcement officer; 3) traveling on business, including to and from customer/business contacts; or 4) engaging in a work activity in which the aircraft is the work environment. Denominator data for rates were based on 1990 U.S. Bureau of the Census and Alaska Department of Labor estimates.

During 1990-1994, a total of 876 aircraft crashes occurred in Alaska; of these, 405 (46%) were occupational. Overall, 106 (12%) crashes resulted in at least one fatality, and 69 (65%) of these were classified as occupational. Of these, 62 (90%) involved fixed-wing aircraft, and seven (10%) involved helicopters. Nearly all (61 [98%]) of the fixed-wing crashes involved propeller-driven aircraft; 54 (89%) were single-engine aircraft. No occupational fatalities occurred on scheduled commercial airline operations.

A total of 192 occupants were on board the 69 aircraft involved in the fatal occupational crashes; 149 (78%) of these occupants were killed. Of the 149 fatalities, 99 (66%) were occupation-related. The annual occupational fatality rate for pilots in Alaska was 268 per 100,000, 2.1 times higher than the U.S. pilot-specific rate of 126 per 100,000 (1). For all workers in Alaska, regardless of occupation, the death rate for work-related aircraft crashes was 8.3 per 100,000, 27.1 times higher than the U.S. rate of 0.3 per 100,000 (1).

The mean number of persons on board the aircraft was 2.8 (range: one-11); in 23 (33%) of these crashes, only the pilot was on board at the time of the crash. The mean age of the occupational decedents was 39 years (range: 20-68 years), and most (58 [59%]) were aged 30-44 years. In addition, nearly all (96 [97%]) deaths occurred among men. The most common cause of death was multiple impact injuries (48 [48%]), followed by head injuries (27 [27%]) and injuries to the chest (11 [11%]).

The takeoff and landing phases of flight together accounted for 228 (56%) occupational crashes, but for only eight (12%) of the fatal occupational crashes. Most (137 [60%]) of these crashes were associated with unimproved, off-airport sites (e.g., sandbars, mountain ridges, and meadows). Controlled flight into terrain during the cruise phase of flight (i.e., straight and level flying) or the maneuvering phase of flight (i.e., changing altitude or direction) together accounted for 46 (67%) fatal occupational crashes. The most common (28 [41%]) impact sites of fatal crashes were mountain sides and passes.

The Federal Aviation Administration (FAA) defines two categories of flying conditions based on meteorologic considerations. Instrument Meteorological Conditions (IMC) exist when visibility is [is less than] 1 mile or the aircraft cannot be operated clear of clouds or overcast; in IMC, pilots must rely on instrumentation for navigation. Visual Meteorological Conditions (VMC) exist when visibility is [is greater than or equal to] 1 mile and pilots can use visual cues for navigation. In Alaska, crashes occurring under IMC were 5.3 times (95% confidence interval=3.5-7.9) more likely to be associated with a death than crashes in VMC.