There are plenty of questions in the wake of an aircraft crash which has claimed the lives of three U.S. Marines. 

They died yesterday off the coast of northern Australia, during a routine military exercise.  

The Marine Rotation Force says five others have been transported to Royal Darwin Hospital in a serious condition.  

International Correspondent Steve Price told Mike Hosking that there were 23 Marines on the Osprey tilt-rotor aircraft when it crashed. 

He says the crash occurred on the Tiwi Islands at approximately 9.30 a.m 

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