On Tuesday, FAA gave approval to a drone large enough to carry tanks of fertilizers and pesticides to spray crops in the United States. The drone called RMAX has been developed by Steve Markofski, currently working with Yamaha Corp. USA. It is a remotely piloted helicopter that weighs 207 pounds (94 kilograms) and capable of carrying 61 pounds of liquid spray or granules for crop dusting.

The radio-controlled craft is powered by a 21-horsepower two-stroke engine, essentially a riding lawnmower engine.

Markofski said that smaller drones have already won approval for limited use to take pictures that help farmers identify unhealthy crops. However, a drone big enough to carry a payload has been approved by federal officials for the first time.

The drone already has been used elsewhere. Recently, the RMAX gained approval for use in Australia by the Civil Aviation Safety Authority (CASA). It has also flown for agricultural purposes in South Korea.

Overall, RMAX aircraft have logged over 2 million flight hours, responsible for spraying about 40% of Japan's rice crop today.

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

According to Ken Giles, professor of biological and agricultural engineering at the University of California, Davis, RMAX is best suited for precision spraying on California's rolling vineyards. It is also used in places that are hard to reach from the ground or with larger, piloted planes. The aircraft was tested by Giles in California to see if it could be used here.

Brian Wynne, president and CEO of the Association for Unmanned Vehicle Systems International, said that the approval highlights other potential uses. According to him, the FAA is taking an important step forward to help more industries realize the benefits drone technology.