<P> Jesus nut, or Jesus pin, is a slang term for the main rotor retaining nut that holds the main rotor to the mast of some helicopters, such as the UH - 1 Iroquois helicopter; or more generally is any component that represents a single point of failure with catastrophic consequences . </P> <P> The term jesus nut may have been coined by American soldiers in Vietnam; the Vietnam War was the first war to feature large numbers of soldiers riding in helicopters . </P>

What is the jesus nut on a helicopter