EMS helicopter crashes: what influences fatal outcome?

STUDY OBJECTIVE: In recent years, air transport of patients has been associated with disproportionate increases in crashes and deaths. We identify factors related to fatal outcome in air medical helicopter crashes and suggest preventive measures. METHODS: This was a retrospective study using National Transportation Safety Board records for helicopter emergency medical services (EMS) crashes between January 1, 1983, and April 30, 2005. The main outcome measure was the percentage of air medical crashes resulting in 1 or more deaths. RESULTS: There were 182 helicopter EMS crashes during the 22.3-year study period; 39% were fatal. One hundred eighty-four occupants died: 45% of the 44 patients and 32% of the 513 crewmembers. Fifty-six percent of crashes in darkness were fatal compared with 24% of crashes not in darkness. Seventy-seven percent of crashes in instrument meteorological conditions were fatal compared with 31% in visual conditions. Thirty-nine percent of all deaths occurred in crashes with postcrash fires; 76% of crashes with postcrash fire were fatal compared with 29% of other crashes. Multivariate logistic regression revealed that controlling for other factors, the odds of fatal outcome was increased by postcrash fire (odds ratio [OR] 16.1; 95% confidence interval [CI] 5.0 to 51.5], bad weather (OR 8.0; 95% CI 2.4 to 26.0), and darkness (OR 3.2; 95% CI 1.3 to 7.9). CONCLUSION: Fatalities after helicopter EMS crashes are associated especially with postcrash fire and with crashes that occur in darkness or bad weather and can be addressed with improved crashworthiness and measures to reduce flights in hazardous conditions. Further studies will be necessary to determine which changes will decrease the fatal crash rate and which are cost effective.

Characteristics of alcohol-related fatal general aviation crashes.

BACKGROUND: The effects of alcohol on piloting performance have been studied extensively. Information describing alcohol-related aviation crashes, however, is scant. METHODS: We developed a data system for fatally injured pilots in Maryland, New Mexico, and North Carolina by linking autopsy data from the state medical examiner offices and crash investigation reports from the National Transportation Safety Board. Alcohol-related crashes are defined as those in which the pilot had a blood alcohol concentration of 20 mg/dL or greater. Differences between alcohol- and non-alcohol-related crashes were assessed with regard to pilot characteristics, crash circumstances, and human factors. RESULTS: The National Transportation Safety Board recorded 313 general aviation crashes fatal to the pilot in the three states between 1985 and 2000. Of these crashes, 255 (81%) were matched successfully with medical examiner records. Alcohol testing results were available for 233 of the fatally injured pilots. Of those tested for alcohol, 25 (11%) had blood alcohol concentrations > or =20 mg/dL (mean=75 +/- 64 mg/dL). The majority of alcohol-related crashes (52%) occurred at night (7p.m. to 6a.m.), compared with 28% of other crashes (P < 0.01). Alcohol-related crashes were significantly more likely than other crashes to have involved continued flight under visual flight rules (VFR) into instrument meteorological conditions (IMC) (32% versus 12%, P < 0.01), and flawed decisions (64% versus 41%, P = 0.03). CONCLUSIONS: Distinctive epidemiological patterns are exhibited in alcohol-related fatal general aviation crashes. Alcohol appears to play a particularly important role in crashes involving flight under VFR into IMC.

Human factors in aviation crashes involving older pilots.

BACKGROUND: Pilot errors are recognized as a contributing factor in as many as 80% of aviation crashes. Experimental studies using flight simulators indicate that due to decreased working memory capacity, older pilots are outperformed by their younger counterparts in communication tasks and flight summary scores. OBJECTIVE: This study examines age-related differences in crash circumstances and pilot errors in a sample of pilots who flew commuter aircraft or air taxis and who were involved in airplane or helicopter crashes. METHODS: A historical cohort of 3306 pilots who in 1987 flew commuter aircraft or air taxis and were 45-54 yr of age was constructed using the Federal Aviation Administration's airmen information system. Crash records of the study subjects for the years 1983-1997 were obtained from the National Transportation Safety Board (NTSB) by matching name and date of birth. NTSB's investigation reports were reviewed to identify pilot errors and other contributing factors. Comparisons of crash circumstances and human factors were made between pilots aged 40-49 yr and pilots aged 50-63 yr. RESULTS: A total of 165 crash records were studied, with 52% of these crashes involving pilots aged 50-63 yr. Crash circumstances, such as time and location of crash, type and phase of flight, and weather conditions, were similar between the two age groups. Pilot error was a contributing factor in 73% of the crashes involving younger pilots and in 69% of the crashes involving older pilots (p = 0.50). Age-related differences in the pattern of pilot errors were statistically insignificant. Overall, 23% of pilot errors were attributable to inattentiveness, 20% to flawed decisions, 18% to mishandled aircraft kinetics, and 18% to mishandled wind/runway conditions. CONCLUSIONS: Neither crash circumstances nor the prevalence and patterns of pilot errors appear to change significantly as age increases from the 40s to the 50s and early 60s.