Investigators hope to reconcile the altitude differences with data from the helicopter's black box, which is taking more time ...

Preliminary data from the deadliest U.S. aviation accident in nearly 25 years showed conflicting readings about the altitudes of an airliner and Army helicopter when they collided near Washington.

Victims' families gathered near the site where a plane and copter collided and fell into the Potomac River. 'They are all ...