Aviators in critical missions will continue air operations (Image by CW2 Cameron Roxberry)|Public Domain

The US Army grounded aviation training units following the death of 12 soldiers in recent helicopter crashes in Alaska and Kentucky.

Units will be grounded until they complete the training. For active-duty units training is from May 1 to 5; Army National Guard and Reserve units have time till May 31.

Aviators in critical missions will continue air operations.

Frequent crashes
On Thursday, three soldiers were killed when two army helicopters collided near Healy, Alaska. The aircraft from the 1st Attack Battalion, 25th Aviation Regiment at Fort Wainwright, near Fairbanks, were returning from training.

It is the second accident involving military helicopters in Alaska this year.

In February, two soldiers were injured in an Apache helicopter crash at Talkeetna. 

In March, nine soldiers were killed when two US Army Black Hawk medical evacuation helicopters crashed in Kentucky.

The Army has found no pattern in the accidents.