Just offshore of the towering national monuments of Washington, a tall crane now hovers over the Potomac River. It casts a large shadow over the effort to understand what caused the collision of a passenger jet and a military helicopter last Wednesday as a new phase of the recovery starts.

Recovery crews using a waterborne crane began raising the wreckage of an airliner from the icy Potomac River on Monday as divers, engineers, pathologists and others worked to account for still-missing crash victims,

Crews have begun removing wreckage from the Potomac River from the deadly midair collision last week that killed 67 people. Col. Francis B.