A four axle AT crane overturned at a Shell facility in New Plymouth, New Zealand earlier today, no one was injured in the incident.The crane owned, by Titan crane hire, was working at the Shell Todd tank farm when it went over. It is not clear what caused the crane to lose stability, the outriggers appear to have been properly set with wood mats under each jack.
So barring any other explanations it looks like a classic stability overload. The Department of Labour is investigating the incident.
Source: