Epidemiology of helicopter accidents: Trends, rates, and covariates

Churchwell, Jared S.; Zhang, Katherine S.; Saleh, Joseph H.

doi:10.1016/j.ress.2018.08.007

Cited by 18 publications

(11 citation statements)

References 8 publications

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“…The end-objective is to contribute toward improving the safety track record of helicopters, and ultimately to reduce the burden of injuries, fatalities, and financial losses due to helicopter accidents. In a previous work, we examined trends, rates, and factors associated with helicopters accidents [1]. We controlled for number of main rotor blades, engine type (turboshaft versus reciprocating), and number of engines (single versus twin).…”

Section: Introductionmentioning

confidence: 99%

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

et al. 2019

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In this work, we establish that maintenance and inspection are a risk factor in helicopter accidents. Between 2005 and 2015, flawed maintenance and inspection were causal factors in 14% to 21% of helicopter accidents in the U.S. civil fleet. For these maintenance-related accidents, we examined the incubation time from when the maintenance error was committed to the time when it resulted in an accident. We found a significant clustering of maintenance accidents within a short number of flight-hours after maintenance was performed. Of these accidents, 31% of these accidents occurred within the first 10 flight-hours. This is reminiscent of infant mortality in reliability engineering, and we characterized it as maintenance error infant mortality. The last quartile of maintenance-related accidents occurred after 60 flight-hours following maintenance and inspection. We then examined the “physics of failures” underlying maintenance-related accidents and analyzed the prevalence of different types of maintenance errors in helicopter accidents. We found, for instance, that the improper or incomplete (re)assembly or installation of a part category accounted for the majority of maintenance errors with 57% of such cases, and within this category, the incorrect torquing of the B-nut and incomplete assembly of critical linkages were the most prevalent maintenance errors. We also found that within the failure to perform a required preventive maintenance and inspection task category, the majority of the maintenance programs were not executed in compliance with federal regulations, nor with the manufacturer maintenance plan. Maintenance-related accidents are particularly hurtful for the rotorcraft community, and they can be eliminated. This is a reachable objective when technical competence meets organizational proficiency and the collective will of all the stakeholders in this community. We conclude with a set of recommendations based on our findings, which borrow from the ideas underlying the defense-in-depth safety principle to address this disquieting problem.

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Section: Introductionmentioning

confidence: 99%

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

et al. 2019

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“…Epidemiological models consider that the spread of events can be modeled using the same analogy of spread of a disease. Accidents are the result of manifest and latent events that take place under epidemic context [127,128].…”

Section: Domino Effect Treatmentmentioning

confidence: 99%

Analysis and Characterization of Risk Methodologies Applied to Industrial Parks

et al. 2020

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It is important to evaluate the risks in industrial parks and their processes due to the consequences of major accidents and especially the domino effect. Scientific works present a wide possibility of models to deal with these situations. In this work, based on the information extracted from the scientific literature, six groups of risk methodologies are defined, analyzed, and characterized with methods that cover the standards, preventive, probabilistic, traditional, modern, and dynamic evaluation that are applied or could be used in industrial parks. It also tries to achieve the objective of determining which are more appropriate if the possible situations and causes that can produce an accident are taken into account, identifying and evaluating them with characteristics of simultaneity and immediacy, determining the probability of an accident occurring with sufficient advance in time to avoid it under the use of a working operational procedure. There is no definitive methodology, and it is necessary that they complement each other, but considering the proposed objective, the integrated application of traditional methodologies together with the management of safety barriers, the dynamic evaluation of risks, and the inclusion of machine learning systems could fulfill the proposed objective.

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“…This requires some detailed explanation. It was addressed in a previous work by Churchwell et al [1], and it is worth repeating here for ease of reading and to keep this work self-contained. Limited helicopter flight-hours data are collected in the US.…”

Section: Limitationsmentioning

confidence: 99%

“…For context, the fatal accident rate of civilian helicopters in the U.S. has shown little or no progress over the last decade, and it is about 17 times higher than fatal accident rates of passenger cars. Over 120 helicopter accidents occur every year, with several hundred injuries and fatalities, and a few hundred million dollars in yearly losses (details in Churchwell et al [1], and Saleh et al [2]). These issues are cursorily noted to motivate the need for more research into helicopter accidents and for more vigorous safety intervention efforts by the regulators and other stakeholders in this industry.…”

Section: Introductionmentioning

confidence: 99%

“…Such findings, however, have to be interpreted cautiously because the lack of exposure data in these studies (the absence of denominator for calculating accident rates, such as total number of medical helicopters in operation or their total flight hours). A more extensive literature review can be found in the related articles by the authors [1,2].…”

Section: Introductionmentioning

confidence: 99%

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Statistical learning for turboshaft helicopter accidents using logistic regression

et al. 2020

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The objective of this work is to advance the understanding of helicopter accidents by examining and quantifying the association between helicopter-specific configurations (number of main rotor blades, number of engines, rotor diameter, and takeoff weight) and the likelihood of accidents. We leverage a dataset of 8,338 turboshaft helicopters in the U.S. civil fleet and 825 accidents from 2005 to 2015. We use the dataset to develop a logistic regression model using the method of purposeful selection, which we exploit for inferential purposes and highlight the novel insights it reveals. For example, one important question for the design and acquisition of helicopters is whether twin-engine turboshaft helicopters exhibit a smaller likelihood of accidents than their single-engine counterparts, all else being equal. The evidence-based result we derive indicates that the answer is contingent on other covariates, and that a tipping point exists in terms of the rotor diameter beyond which the likelihood of accidents of twin-engines is higher (worse) than that of their single-engine counterparts. Another important result derived here is the association between the number of main rotor blades and likelihood of accidents. We found that for single-engine turboshaft helicopters, the four-bladed ones are associated with the lowest likelihood of accidents. We also identified a clear coupling between the number of engines and the rotor diameter in terms of likelihood of accidents. In summary, we establish important relationships between the different helicopter configurations here considered and the likelihood of accident, but these are associations, not causal in nature. The causal pathway, if it exists, may be confounded or mediated by other variables not accounted for here. The results provided here lend themselves to a rich set of interpretive possibilities, and because of their significant safety implications they deserve careful attention from the rotorcraft community.

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Epidemiology of helicopter accidents: Trends, rates, and covariates

Cited by 18 publications

References 8 publications

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

Analysis and Characterization of Risk Methodologies Applied to Industrial Parks

Statistical learning for turboshaft helicopter accidents using logistic regression

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