Safety of twin-engine helicopters

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Publication Date:	01-2021
Authors:	Elena St. Amour Alex de Voogt

de Voogt, A., & St. Amour, E. (2021). Safety of twin-engine helicopters: Risks and operational specificity. In Safety Science (Vol. 136, p. 105169). Elsevier BV. https://doi.org/10.1016/j.ssci.2021.105169

Abstract

Objectives: To examine the difference between twin-engine and single-engine helicopter operations and accidents, and to understand the main factors that are associated with fatal twin-engine helicopter accidents.

Methods: Data concerning a ten-year period taken from the US National Transportation Safety Board online database on twin-engine helicopter accidents were analyzed and compared to a dataset of single- and twinengine helicopter accidents in Part 135 Air Taxi and Commuter operations.

Results and recommendations: Twin-engine helicopters show a lower risk of accidents compared to single-engine helicopters but with a similar proportion of fatal accidents. Twin-engine helicopters show a frequent involvement in air medical operations, which expose pilots more often to night and IMC flight conditions that are significantly more often associated with fatal accidents. The differences in accident rate cannot be explained by the profile of the pilots, the kind of accident causes or their type of operations but may possibly be associated with differences in geographical location or type of organization.