Air Tour Helicopter Accidents (2014 to 2024): A Data-Driven Exploration of Causal and Contributing Factors

Abstract:
Helicopter air tours operate in one of the most challenging and least-controlled environments of commercial aviation, yet the safety outcomes of these operations remain inconsistent across regulatory frameworks. This study examined 55 helicopter air tour accidents in the United States from 2014 to 2024 using data from the NTSB Case Analysis and Reporting Online database. Defining event narratives, contributing factors narratives, and probable cause were coded to identify causal relationships between accidents and identify safety trends between 14 CFR Part 91 operations and Part 135 operations. CFR Part 91 operations exhibited accident rates approximately three times higher than Part CFR 135, averaging 3.94 per 100,000 flight hours compared to 1.23. Maintenance/mechanical was the most common initiating cause for accidents under CFR Part 91, accounting for 52% of cases compared to 37% under Part 135. Pilot/related cases were more prevalent under CFR Part 135, accounting for 53% of accidents. The two regulatory frameworks operated substantially different fleets, with CFR Part 91 relying on reciprocating-engine helicopters (76%) and Part 135 on turbine-powered aircraft (81%). Engine and powerplant/related events accounted for 27% of all defining events, and nearly half of all events involved a technical or mechanical initiator.

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