AKDOT Employing Drone Tech for Inspections


Because of their ease of use and increased safety for workers, several state Departments of Transportation are turning towards utilizing autonomous drones to perform inspections on critical infrastructure. This technology can reportedly improve workflow efficiency and lower costs, as well.

The Federal Aviation Administration estimates that by 2025, there could be a total of more than 2.6 million commercial and recreational drones flying in U.S. airspace. Currently, there are more than 860,000 drones registered in the country, or about three times as many crewed aircraft.

“It’s critical that we have a standard set of rules for operations beyond visual line of sight – or BVLOS, as we call it – where you no longer have eyes on the drone. This would enable operations for things like routine package deliveries, infrastructure inspections and agriculture spraying and inspection,” said Acting FAA Administrator Billy Nolen at the White House Summit on Advanced Air Mobility last month.

Autonomous drones are unmanned aerial vehicles (UAVs) that can use artificial intelligence-powered navigation and operation software to take flight, and therefore can be operated by less experienced pilots.

The use of drones allow for safer and more frequent inspection, with continual monitoring of structures and providing up-to-date data. Autonomous drones can also get close-up in inaccessible areas, potentially finding anomalies that prevent structural failure and faster repair.

With manual drone inspections, a less experienced pilot might not be able to operate around low bridges. It is also more difficult to operate in a GPS-denied environment, more expensive and is harder to receive a waiver to fly compared to autonomous drones.

“They are a lot easier to fly than a traditional manual drone,” according to David Buhrman, Senior Solutions Engineer of drone company Skydio.

Skydio autonomous drones are used by the Alaska Department of Transportation, which performs an average of eight to 12 bridge inspections daily. For these inspections, the team uses the company’s 3D Scan software to automate the data capture process for generating 3D models of infrastructure.

“This has been a fantastic breakthrough for us—to take all of that data and visualize it, and do change detection,” Ryan Marlow, UAS Program Coordinator, Statewide Aviation for AKDOT, shared during a webinar hosted by the Association for Unmanned Vehicle Systems International last month.

“We’re seeing a lot of success with the 3D Scan with our engineers in the field.”

The first inspection completed by the drones was on a pedestrian bridge over a creek in Juneau. The bridge had reportedly undergone numerous manual inspections, but the drone was able to capture a previously undetected structural issue that needed repair.

“We were able to see something leaking out of the timbers,” Marlow said. “It allowed us to capture this environment in a way that we’d never been able to visualize.”

According to reports, the data collected via autonomous drones is also useful for measuring changes in critical infrastructure over time, allowing the AKDOT to prioritize the most urgent repairs. 

Buhrman explained that Skydio’s UAS uses six 4K cameras that work together to visualize its surroundings. Navigation is supported by learning algorithms and advanced predictive artificial intelligence to make decisions, with close proximity obstacle avoidance.

Previously, in 2020, the drones were used by North Carolina’s DOT for bridge inspections, as part of a collaboration between NCDOT, Skydio and the FAA. Buhrman noted that the company has also recently partnered with DroneDeploy to automate the data analysis process, importing imagery for immediate processing.

“Under Part 107, the FAA does require a remote pilot in command to be present with the aircraft that can see attitude, altitude, and position of the aircraft at all times,” he remarked. “There is no directive about flying in an automated fashion, as long as the pilot can take over for manual flight in an emergency situation.”

Drone Infrastructure Inspection Bill

Last month, several U.S. Senators introduced companion legislation to the bipartisan Drone Infrastructure Inspection Act that was passed by the House Transportation and Infrastructure Committee in April.

Following its clearance with the committee, the Drone Infrastructure Inspection Grant Act now moves to the House floor for voting. It was first introduced by Arizona Rep. Greg Stanton and Louisiana Rep. Garret Graves.

H.R. 5315 would authorize $100 million in competitive grants to use American-made drones to perform critical infrastructure inspection, maintenance or construction projects. Additionally, it would make another $100 million available for drone education and workforce training.  

Stanton noted that many state department of transportation, tribes and municipalities already use drones to augment human inspections when inspecting bridges, roads, dams and electric substations. The Arizona Department of Transportation reportedly uses drones to inspect bridges and perform surveying work along state highways. 

Additionally, the drones could be used to inspect areas after natural disasters to determine the extent of damage and whether areas are safe.

On Aug. 4, it was announced that U.S. Senators Jacky Rosen (D-Nevada), John Boozman (R-Arkansas) and Richard Blumenthal (D-Connecticut) introduced the companion bipartisan legislation. Government entities can reportedly use the grant funding to purchase drones, buy drone inspection systems and help unmanned aircraft system program capabilities.

The introduced legislation also aims to help universities access grants to train drone-operating workers. Alongside education and training, it would provide $50 million in both fiscal year 2022 and 2023 for both types of grants, totaling $100 million in grants for each year.

Drones for Inspection

In 2020, a Victoria, British Columbia-based technology company hoped their drones would be used for maintaining infrastructure across Canada, the United States and around the globe. However, beyond inspections, the system could also be used to track damage over time so civil engineers can plan preventive maintenance.

“We started with dams but the next thing we’re doing is going into bridges and tunnels, even nuclear power plants, water tanks, all types of concrete structures, and then slowly going to steel and timber structures as well,” said Harsh Rathod, co-founder of Niricson at the time. “We can apply it to any type of asset.”

According to the Journal of Commerce, the drone technology uses visual, acoustical and infrared heat sensing to inspect what’s underneath an infrastructure’s concrete surface. The combination of technology can reportedly detect cracks, voids or other issues by flying around the structure and collecting information using its onboard acoustic recorder, optical camera and infrared camera.

Once the data is collected, it is then immediately analyzed using Niricson’s software—developed three years ago by Rathod and his PhD supervisor Rishs Gupta—which can further indicate the width, length, depth and overall significance of the defects and, if necessary, can start taking actions to repair them.

Last year, the Minnesota Department of Transportation utilized high-resolution drone photographs of the James J. Hill Stone Arch Bridge during inspection to utilize with Microsoft HoloLens technology and software from Bentley Systems.

The technology pieced the photos together in a sort of “reality mesh” 3D model comprised of millions of polygons. The result creates what Bentley describes as a mixed-reality workflow, which aims to combine inspection photographs with physically being onsite, without actually having to be onsite.

While the reality mesh can be viewed on a computer or tablet, in using the cloud-connected HoloLens, users can view the bridge at a zoomed-out tabletop view of at a 1:1 scale, allowing engineers to see portions of the structure up close in high resolution. During this type of virtual inspection, the engineer can add annotations, perform measurements, and highlight potential problem areas.

While MNDOT has policies in place governing drone flights for bridge inspections that comply with Federal Aviation Administration regulations, Jennifer L. Wells, MNDOT state bridge inspection engineer, predicts that a version of the workflow could eventually become a standard practice for bridge inspections in the state.

Outside of infrastructure, drones have recently been considered for use in construction. In a comprehensive report released by the New York City Department of Buildings last year, the city contemplated the use of unmanned aircraft systems for facade and safety inspections throughout the area.

According to reports, current legal use of drones in New York City is restricted only to approved government agencies in response to specific emergency response situations. Due to these restrictions, in order for the DOB to use drones commercially, new legislation from the City Council would be required to amend the New York City Administrative Code.

For its study, the DOB investigated how the regulatory landscape could affect drone use in the city, the use of drones in other jurisdictions and how drones could potentially be used for building facade inspections within the five boroughs.

In its report, the DOB found that when used in conjunction with up-close, hands-on examinations, the use of unmanned aircraft systems could potentially have application for facade inspections in that the technology would provide additional information to the Qualified Exterior Wall Inspector.

Ideally, the drones would be utilized to collect significant amounts of visual data such as photographs, videos and thermal imaging. However, the DOB believes that the drones could also be used to capture more difficult images of building angles for large building inspections.

The DOB reports that it will be continuing its research into drone use, accompanying technologies and how the unmanned aircraft systems could be safely employed by its professionals as it believes the combination of emerging technology could improve the efficiency and safety of required building inspections.

In addition, further studies could also offer a glimpse into how drones can be safely operated for broader commercial use in a dense city environment. The City reports that it plans to look into additional rules and specific guidelines it would need to implement if drones were used to help maintain public safety in the future.


Tagged categories: drone; Drones; Health & Safety; Health and safety; Infrastructure; Infrastructure; Inspection; Inspection equipment; NA; North America; Program/Project Management; Quality Control; Technology; Tools & Equipment

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