Wednesday’s fatal collision and two other incidents dramatically illustrate the challenges pilots and air traffic controllers face in the complex, security-sensitive skies above the nation’s capital.

A jet with 60 passengers and four crew members collided with an Army helicopter while approaching Ronald Reagan National Airport near Washington, D.C., sending the two aircraft plummeting into the Potomac River and killing everyone on board.

By LOLITA C. BALDOR, TARA COPP and ERIC TUCKER ARLINGTON, Va. (AP) — At least 28 bodies were pulled from the icy waters of the Potomac River after an American Airlines jet carrying 60