Explained: Investigators look at why a plane was allowed to take off as President Trump's helicopter approached

The NTSB and FAA are investigating why a commercial jet took off as Marine One, carrying President Trump, approached Reagan National Airport on Tuesday afternoon.

NTSB

National Transportation Safety Board, the agency investigating the incident.

FAA

Federal Aviation Administration, the regulator overseeing air traffic safety rules.

Marine One

The call sign for the helicopter used to transport the U.S. president.

loss of separation

A term describing when aircraft come closer together than safety rules allow.

conflicting route

A flight path that intersects or crosses another aircraft's path, posing a collision risk.