The Australian Army grounded the whole fleet of 30 Blackhawk helicopters as a precaution after fractured bolts were discovered during scheduled maintenance.

The location and function of the fractured bolts has not yet been specified, and the grounding remains in force until an investigation is conducted into the fault.

Link ABC News:
http://www.abc.net.au/news/2012-01-21/army-grounds-black-hawks-in-e-timor/3785872?section=world