An American Airlines regional jet went down in the Potomac River near Ronald Reagan Washington National Airport.

An American Airlines regional jet went down in the Potomac River near Ronald Reagan Washington National Airport.

The Black Hawk is a US Army workhorse helicopter. It has been flying for decades. One tragically collided with a passenger jet this week.

An Army Black Hawk helicopter collided midair with an American Airlines flight from Wichita, Kansas, at Reagan National Airport on Wednesday.

A few minutes before the jet was to land, air traffic controllers asked American Airlines Flight 5342 if it could do so on a shorter runway, and the pilots agreed. Controllers cleared the jet to land, and flight tracking sites showed the plane adjust its approach to the new runway.

The Post can reveal that miscommunications in one of the most crowded and complex patches of sky in the US are likely to blame.

Ryan O’Hara, a father-of-one, was one of the three soldiers aboard the military helicopter, according to reports

The Army Black Hawk helicopter that collided with an American Airlines commuter plane near Reagan Washington National Airport in Virginia Wednesday was on a “training flight” when it crashed into the Potomac River, according to the military service branch.

Sixty passengers and four crew members from the plane and three Black Hawk helicopter personnel are feared dead as a recovery mission is underway.

The Army official said that the pilots were on a routine training flight along a familiar flight path that isn't particularly complicated.

According to the FAA, an Army Black Hawk helicopter collided into a 60-passenger flight landing at DCA midair.