The US Marine Corps on Friday ordered its aircraft squadrons to suspend flight operations for 24 hours sometime during the next two weeks to review procedures after two of its planes crashed, killing dozens.General Robert Neller, commandant of the US Marine Corps, directed aviation units to time the suspensions in a way that would not disrupt "operational commitments," the Marine Corps said in a statement on Friday. Commanders will determine the schedule for their units."Pauses in operations are not uncommon and are viewed as a responsible step to refresh and review best practices and procedures so our units remain capable, safe, and ready," the statement said.Last weekend, a Marine MV-22 Osprey tilt-rotor aircraft crashed off northeastern Australia, killing three Marines aged 19 to 26. Twenty-three others on the craft were rescued.In July, a KC-130 Hercules transport plane crashed in Mississippi, killing 16 service members, including reservists from New York state and active-duty Marines based in North Carolina.The Osprey is built by Boeing Co and Textron Inc's Bell Helicopter. It is designed to lift off like a helicopter and then rotate its blades to fly like a plane.The KC-130 Hercules is produced by Lockheed Martin Corp . It carries cargo, conducts in-air refueling, and can carry 92 ground troops or 64 paratroopers, according to the US Navy website.Last December, the US grounded its MV-22 Osprey aircraft in Japan at the request of Tokyo following a crash southwest of Okinawa. The aircraft has been a lightning rod for opponents to the heavy US military presence on Okinawa, which lies south of the main Japanese island group.