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.

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

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 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.

An American Airlines jet collided midair with a military helicopter near Reagan National Airport. Four crew and 60 passengers were on board the plane.

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

The NTSB shared photos of one of the black boxes that was recovered from the American Airlines jet that crashed near Washington.

One of the victims of the American Airlines crash has been identified as a Connecticut youth soccer coach and father of three by state officials.

The Army helicopter and regional American Airlines jet that collided over Washington are both workhorse aircraft that operate around the world on a daily basis. There were 60 passengers and four crew members on the jet,

The airspace around Washington, D.C., is congested and complex — a combination aviation experts have long worried could lead to catastrophe.