The move comes after two AH-64 Apache helicopters collided in Alaska, killing three soldiers and injuring another, and two Black Hawks crashed in Kentucky, resulting in nine deaths.

General James McConville has ordered an aviation stand down, which will involve reviewing risk management processes, aviation maintenance training programs, aircrew training standardization and management, and supervisory responsibility.

Active-duty units have been ordered to complete a 24-hour stand down between May 1 and 5, while National Guard and Reserve units have until May 31.

The US military has experienced multiple other aircraft crashes in recent years, including the deaths of four Marines during NATO exercises in Norway and two Navy pilots in a T-45C Goshawk jet crash in Texas. (ILKHA)