Abstract:
The objective of this work and its companion article is to provide a better understanding of helicopter accidents and to identify areas that deserve careful attention for improving safety and accident prevention. Three broad questions were here investigated: (1) whether there are safety blind spots in helicopter inspections and any association between inspection time and accidents? (2) whether there are geographic disparities in helicopter accident rates in the U.S. at the regional and state level? And (3) whether there is any association between pilot age and flight experience, and helicopter accident rates? Record Linkage of two Federal data sources, the FAA civil helicopter registration data and the NTSB accident data, enabled the investigation of these and other questions. The main results included the following. First, it was found that there is a clear and significant association between the time of inspection and the accident occurrence, with 10% of all accidents occurring within 4 flight hours of an inspection (all types of inspections). Second, it was found that there are clear and statistically significant geographic disparities in helicopter accident rates in the U. S., both at the regional and state level. Some of the worst-in-class states (e.g., Arkansas, Utah, West Virginia) have helicopter accident rates that are an order of magnitude higher than the best-in-class (e.g., Vermont, Connecticut). Third, it was found that the likelihood of a helicopter pilot to be in an accident is independent of his or her age. Possible confounders were discussed, and hypotheses were proposed as well as recommendations for the FAA and other stakeholders. The end-objective of these recommendations is to improve the safety track record of helicopters, to advance accident prevention, and to reduce their burden of injury, death, and financial losses.