Pilots were disorientated in fatal Louisiana Army National Guard UH-60 crash

The pilots of a U.S. Army helicopter that crashed into a Florida bay in March, killing 11 service members, lost control of the aircraft after becoming disoriented in heavy sea fog, the military said on Thursday.

An investigation found that the two pilots failed to switch from using visual flight procedures to instruments that could have helped them navigate the foggy conditions they encountered during the nighttime training exercise, according to a statement from the Louisiana National Guard.

Four guard soldiers and seven Marines from a special operations unit from Camp Lejeune in North Carolina died when the UH-60 Black Hawk helicopter plunged into waters off the Florida Panhandle on March 10. The pilots were among those killed.

A second helicopter in the exercise turned back due to the weather and landed safely.

"Training for high-risk, realistic missions is something these service members accepted on a regular basis to be able to do their job when called upon," said Major General Glenn Curtis, adjutant general of the Louisiana National Guard.