Marine Corps aviation units have been ordered to ground all aircraft for 24 hours to focus on safety.Gen. Robert Neller, Marine Corps commandant, said unit commanders could schedule the pause at their discretion within a two-week period. A statement said the halt to flight operations will not affect operational commitments.The order comes after two recent crashes of Marine Corps aircraft.Last weekend, a Marine Corps MV-22 Osprey crashed off the coast of Australia. Three Marines died in the crash.July 10, a Marine Corps C-130 crashed in Mississippi. All 16 aboard were killed: 15 Marines and a Navy corpsman.As yet, investigators have not announced a cause for either crash.The Marine Corps statement said aviation units will use the 24-hour suspension: