Unmanned flight prepares to move deeper into the agriculture sector, now that federal regulators have approved Yamaha's crop dusting drone.

Yamaha's 207-pound (94 kilograms) RMAX can deliver and disperse tanks of fertilizer and pesticides across large swathes of land.

The unmanned helicopters have been in use in Japan for years, but the Federal Aviation Administration (FAA) finally gave clearance to the drones in the U.S. late last week. Stateside, farmers had only been allowed to survey their lands with drones.

"The enhanced safety achieved using [an unmanned aircraft] with the specifications described by [Yamaha] and carrying no passengers or crew, rather than a manned aircraft of significantly greater proportions, carrying crew in addition to flammable fuel, gives the FAA good cause to find that the UAS operation enabled by this exemption is in the public interest," stated [pdf] the FAA.

In approving the RMAX, the FAA imposed 28 conditions and one of the first of those was the declaration that the approval only applied to the Yamaha drone. All others will need individual approval.

The RMAX will be limited to operating at speeds no more than 45 MPH and a max altitude of 400 feet above ground level. The drone pilot and another observer will have to maintain a direct line of sight with the RMAX whenever it is in operation.

"I certainly understand their cautious approach," said Yamaha spokesperson Steve Markofski. "It's a daunting task given our airspace is complicated."

The world is finally ready for drones, with the rise of drone warfare and the proliferation of amateur drone pilots, but the RMAX has been in operation since 1997 and the FAA says there are about 2,600 of the unmanned air vehicles in operation. Agriculture is one of the more compelling use cases for the RMAX, but Yamaha says there are many others.

"Unmanned vehicles are ideally suited to dirty, dull and dangerous tasks," says Yamaha. "To this end RMAXs have been used to inspect active volcanoes, disaster zones and otherwise inaccessible sites. RMAX is used by many universities and research institutions. They are favored as a stable and reliable platform. RMAX has been used as photography, surveillance, photogrammetry and information gathering."

Take a look at this test flight of a Yamaha RMAX: