A military helicopter was flying above the maximum altitude for its route when it collided with a passenger plane near Washington D.C. last week, authorities said. The National Transportation Safety ...

The Army pilots were juggling dark skies, low altitude, a busy airspace and a cockpit without certain traffic detectors before the helicopter’s midair crash with a regional passenger jet.

Data from air traffic control radar showed the military chopper was flying at 300 feet on the air traffic control display at ...