Using mostly open-source software, the company hosts an online portal so clients can access the deliverables, including photomosaics, 3D point clouds and digital terrain models. The data can be imported into most engineering software.

Sherwin's favorite rig is the TBS Discovery Pro, a prosumer-grade quadcopter that comes as a kit and costs about $1,600. It weighs just 4 lbs. The copter's logic board doubles as its chassis. Sherwin's carries a GoPro still and video camera on a brushless-motor gimbal, and a global-positioning system. Its aerial scans can produce images with 3- to 7-cm resolution. Close-range facade scans can capture details as fine as 1 mm, Sherwin says. The GPS is accurate to 2.5 m, but the scanned mosaics are much more accurate due to the triangulation of pictures, he says, adding, "If we have actual surveyed ground control, the accuracy can be incredible."

Sherwin says one limitation of UAV use for inspection, though, is that operators can't yet touch or hammer surfaces, like concrete, to check for spalling. Otherwise, Sherwin says, "the opportunities are immense."

Sherwin and Burnett are by no means alone in banking on the NTSB judge's ruling and launching their UAVs. Pat Fuscoe, CEO of Fuscoe Engineering, Irvine, Calif., also believes the NTSB decision supersedes FAA policy, but still he treads with care. His operator is a licensed pilot, and Fuscoe gives clients "complimentary services" of view simulations and preliminary surveys. "The way we look at it, there's no transaction, there's no commercial application," Fuscoe said. "It's a bit of a rationalization, but we're hiding under the NTSB ruling."

John Lovin, senior vice president at Woolpert, Inc., a Dayton, Ohio, design, geospatial and infrastructure firm, is more cautious. His $100,000 Altavian Nova Block III UAV is leased to a local community college, whose students fly it legally, he says, under the umbrella of educational use. The firm uses student flight data to optimize its UAV workflow in anticipation of the day Woolpert can fly its own drone.