U.S.: Marines killed in helicopter training at California’s Camp Pendleton
- what Two military helicopters collided in midair Wednesday night. The collision, which happened during a routine training session along the Arizona-California border, killed seven U.S. Marines.
- why The investigation is still on-going, so officials have not announced the cause of the collision. The crash occurred at night with a lot of dust in the air from the aircraft, limiting visibility. source