A combination of turbulence and flight speed has been blamed for a helicopter crash that killed its pilot in Wanaka two years ago.
The Transport Accident Investigation Commission's final report says experienced pilot Matthew Wallis died when his Robinson R-44 broke apart mid-flight.
The damage was caused by a problem known as mast-bumping, which occurs when a two-bladed teetering rotor head see-saws so much that it breaks its own drive shaft.
The fault has been central to other crash investigations involving Robinson helicopters and has resulted in 20 deaths in New Zealand over the last 30 years.
The Commission's chief commissioner is Jane Meares, she speaks to Susie Ferguson.
