A causal factors analysis of helicopter accidents in New Zealand 1996-2005 and the United Kingdom 1986-2005

Abstract

Abstract Helicopter accidents cause many fatalities, and their avoidance is a major area of work for Civil Aviation safety authorities around the World. This paper uses helicopter accident data from the United Kingdom between 1986 and 2005 for 566 accidents and from New Zealand between 1996 and 2006 for 230 accidents to analyse helicopter accidents according to five categories of causes: airworthiness failure (engine); airworthiness failure (non-engine), operational failure, maintenance failure and mixed failure (i.e. operational and airworthiness combined). Factors associated with accidents, e.g. the engine types and weights of the helicopters involved; the nature of the operations and the phase of flight of the helicopter are also analysed. Operational failures were further analysed by Human Factors Analysis and Classification Scheme (HFACS) and airworthiness failures by a logical scheme of helicopter components. The results indicate that operational failures, especially due to unsafe acts, are the major cause of accidents in both countries followed by airworthiness causes. Light single piston helicopters are by far the major group associated with accidents in both countries, with few accidents for twin turbine helicopters. The majority of accidents were in non-public operations with few in public operations and in both countries, the cruise/flight/circuit phase has the largest number of accidents. Further analyses indicated statistically significant associations: type of helicopter and the cause of accidents; type of helicopter and the phase of flight; cause of accidents and nature of flights; cause of accidents and phase of flights; training flights and inadequate supervision; landing and procedural error and cruise and attention failure.