High-risk helicopter operational safety dynamics

Helicopter emergency medical service flights are conducted in hazardous operating conditions often at night and during inclement weather. The proportion of fatal accidents during those operations has remained unchanged over time. This investigation identified operational safety risk factors underlying those accidents with the aim to present quantitative risk assessment guidance material to improve safety and prevent night-time operational accidents. Inexperienced pilots in years within that domain had the greatest likelihood of a non-survivable accident in conditions unsuited for night visual flight rule operations. Prediction models using significant variables are presented as nomograms for guidance material to aid decision making.