War zones: When drones fall from the sky

More than 400 large U.S. military drones have crashed in major accidents around the world since 2001, a record of calamity that exposes the potential dangers of throwing open American skies to drone traffic, according to a yearlong Washington Post investigation.

Since the outbreak of the wars in Afghanistan and Iraq, military drones have malfunctioned in myriad ways, plummeting from the sky because of mechanical breakdowns, human error, bad weather, and other reasons, according to more than 50,000 pages of accident investigation reports and other records obtained under the Freedom of Information Act.

Commercial drone flights are set to become a widespread reality in the United States, starting next year, under a 2012 law passed by Congress.

Drone flights by law enforcement agencies and the military, which already occur on a limited basis, are projected to surge.

The documents obtained by the Post detail scores of previously unreported crashes involving remotely controlled aircraft, challenging the federal government's assurances that drones will be able to fly safely over populated areas and in the same airspace as passenger planes.

Military drones have slammed into homes, farms, runways, highways, waterways, and, in one case, an Air Force C-130 Hercules transport plane in midair. No one has died in a drone accident, but the documents show that many catastrophes have been narrowly averted.

"All I saw were tents, and I was afraid that I had killed someone," Air Force Maj. Richard Wageman told investigators after an accident in November 2008, when he lost control of a Predator that plowed into a U.S. base in Afghanistan. "I felt numb, and I am certain that a few cuss words came out of my mouth."

Investigators were unable to pinpoint a definitive cause for the accident but said wind and an aggressive turn by the pilot were factors.

Several military drones have simply disappeared while at cruising altitudes, never to be seen again.