Sugar Land Regional on the Cutting Edge With Autonomous Mowers

With spring arriving in southeast Texas, the grass will be growing faster than ever at Sugar Land Regional Airport (SGR) near Houston. That means it’s go time for employees who maintain the grounds, including 400 of the airport’s 639 total acres that need to be mowed weekly.

This year, three autonomous mowers are supplementing SGR’s maintenance crews, with each able to mow more than 1.4 acres per hour. And despite some initial trepidation, the human workers are fully embracing their new robot crewmates.

Ken Durbin, assistant director of Aviation for Maintenance and Operations, notes that turf management accounts for 45% of the labor budget for SGR’s Maintenance Division. Due to the temperate climate in Sugar Land, turf management kept a handful of maintenance staff busy for about 44 weeks a year, with little to no time for other tasks. But that is already changing with SGR’s new autonomous mowers on the job.

When the field advisor told Durbin it was time to retire the airport’s aging fleet of mowing equipment. Durbin knew that simply replacing the equipment with like units would not improve efficiencies, so he and his staff began researching other options in 2019. While looking online at the latest equipment, one staffer found autonomous technologies adapted to mowing.

At the same time, Sugar Land’s new city manager was creating the department of Data and Innovation to help various city departments (including the airport) use data to improve efficiency. Rachel Owens, assistant director of Data and Innovation, remembers that Durbin’s main drivers for mowing operations were time and labor management, and she was aware that he and his staff had begun researching autonomous mowing equipment. Her advice to Durbin, and anyone collecting data, is, “Just capture what you already do. It doesn’t have to be complicated. Think of all the metrics of the problem and then compile the information. If you overcomplicate it, you won’t do it.”

Durbin understood that it would take more than estimates calculated with pencil and paper to present a successful argument for a budget increase to purchase new mowers. He needed solid data to determine the labor cost per acre of traditional mowers to compare with similar statistics of autonomous alternatives.

When GPS tracking was miniaturized around 2023, Durbin finally had a way to collect better data. “It became a game changer as small units could be applied to equipment such as mowers,” he recalls. Crews promptly fitted five of SGR’s mowers with GPS trackers to collect turf management production rates. Naturally, there were variations with different machines, operators and types of turf cut, but the GPS data showed an average production rate of 2.48 acres per hour. Durbin was pleased that his “guesstimated” pencil and paper calculations of 2.55 acres per hour were not far off from information the GPS recorded.

Typically, mowing required five to six of the airport’s nine maintenance staffers. “What I wanted to do was save on labor,” he explains. “I wanted to take ‘butts out of seats’ that were mowing seven hours, five days a week, and move those dollars to lighting or other necessary items.”

Weighing the Options

Owens knew that Durbin was keen on autonomous mowing equipment, so when a company selling them approached the city, the opportunity to test the emerging technology became a reality. To encourage efficiency improvements, the city’s innovation fund helps departments try new tech-forward products and services without having to use their own regular operating budgets.

The airport ended up hosting equipment from the mowing robot company for two separate months during fall 2021 and spring 2022. “It gave us an idea of the limitations of these mowers,” Durbin explains. “We were going through a learning process with them.”

Meanwhile, the clock was ticking to replace the airport’s existing mowers; and there was a notable disconnect between what vendors were offering and what Durbin and his staff considered non-negotiable factors.

“We felt the industry just wasn’t there quite yet to allow us to outright own and operate [autonomous mowers],” Durbin recalls, adding that only electric versions were offered at that time.

Although the initial autonomous mowing equipment company was unable to meet SGR’s needs, it gave Durbin and his staff a better idea of what they needed to find. Another internet search in April 2024 turned up RC Mowers, based in Suamico, WI. “I had almost given up before finding RC Mowers and was going to go with the zero-turn, 60-inch cut John Deere mowers as we were already familiar with John Deere,” says Durbin.

Instead, he reached out to the company through its website and asked for a demo of its new AMR A-60 model—a gasoline-powered, zero-turn mower, with 60-inch mowing deck, that can be operated autonomously or run by an operator seated on the unit.

The model was only two years old, and the company’s first trial in an airport environment was dubbed a resounding success. “RC Mowers checked all the boxes,” Durbin summarizes.

And it did so just in time for his budget presentation to the City Council Finance Board. The data showing how much money his department could save by replacing vs. repairing existing equipment and the 11th hour discovery of RC Mowers and associated labor hours its autonomous equipment could save helped secure funds to purchase three A-60 Autonomous Mowing RobotsTM.

One big concern Durbin had was that the City Council would, in turn, trim his personnel budget accordingly. But that didn’t happen because he successfully demonstrated that time saved by the autonomous mowers would allow staff to perform other critical maintenance duties.

Cutting Edge Technology

The airport took delivery of three A-60s in December 2024, and a technical representative from RC Mowers remained on site for two days to train and certify airport staff on the mowers and operating system. After using the new units for a few months, Durbin reports that they have exceeded expectations, with mowing rates greater than 1.4 acres per hour. In fact, if one crew member sets the autonomous mowers and then also operates a standard mower in the same area while monitoring the bots, that crew’s production rate could increase to about 4 acres per hour. As a result, Durbin’s labor cost per acre could decrease from greater than $12 to less than $10 in this scenario.

Tim Kubista, vice president of sales and marketing for RC Mowers, emphasizes that labor is the key challenge for airports and other facility operators. “Sometimes it’s budgets, sometimes it’s lack of people,” he remarks. “These mowers came about with the technology to tackle those challenges.”

Maintenance was another factor that affirmed the A-60s for Durbin. “Because they are on a Gravely^® chassis, our team can maintain belts, wheels, oil, blades—really anything not involving the computers,” he says.

For those issues, RC Mowers provides a computer service agreement along with ongoing reporting and real-time analytics. Maintenance workers operate the mowers through an Android cell phone app. Mowing plans are uploaded from the company’s app to a portal, and can then be assigned to any of the airport’s autonomous mowers.

The system’s connectivity allows Durbin to monitor mowing activity from his office and the flexibility to determine how best to make mowing plans work.

It Can be Personal for Personnel

Both Durbin and Elizabeth Rosenbaum, executive director of Aviation, note that the turf maintenance team was apprehensive when the concept of autonomous mowers was introduced. “We wanted to be clear they were not losing their jobs as there were plenty of other tasks that are our responsibility,” says Durbin. Other duties that fall under their purview include patching spalls on pavement, painting airfield lines and markings, trimming, maintaining signs and markings, changing bulbs in airfield lighting, maintaining tower and terminal facilities, cleaning restrooms, maintaining 11 city-owned hangars and more.

The new equipment from RC Mowers can operate autonomously or with a driver.

Rosenbaum emphasizes that the autonomous mowers are not meant to replace the workers, but to allow their responsibilities to be redefined and skill sets expanded. For instance, if the robot equipment can do the lion’s share of mowing, employees can be trained to do tasks the airport currently contracts out, such as applying airfield markings and pressure washing the pavement.

“Airfield maintenance people are doing more with fewer resources,” Kubista says, adding that mowing is monotonous work that can be especially unpleasant in the Texas summer heat. “The value of the output [of autonomous mowers] is more valuable as the worker is free to do other necessary work.”

On that note, personnel development has become a main priority for Rosenbaum. These days, the airport conducts “stay interviews” with current employees, an innovative twist on exit interviews that help assess satisfaction and other key factors. Rosenbaum reports that stay interviews have revealed that employees want to grow and learn new skills. “When you think of maintenance, there aren’t a lot of ‘new’ tools and technologies out there; so this [the introduction of autonomous mowers] was something new and exciting for them to learn about.”

Safety is No Accident

Although SGR is not a Part 139 airport, Durbin and crew follow Part 139 standards for airfield maintenance and use the FAA Series 150 Advisory Circulars (AC-150) for guidance.

In that vein, Durbin notes that the autonomous mowing robots will not be used inside the taxiway and runway safety areas. “We cannot accept the risk,” he explains, adding that more diligence is required to plan mowing areas when robotic equipment is involved.

“We are serious about safety,” Durbin emphasizes.

In fact, SGR is currently working on a new Safety Management System program.

Unexpected Reactions

Much to Durbin’s surprise and delight, morale is up since SGR implemented its new mowing system. He reports that maintenance employees no longer fear losing their jobs to the automated equipment and they enjoy and take pride in commanding the fleet with a cell phone.

Public reaction to the robot fleet has also been fun for him to watch. “We have stopped traffic on Highway 6 with these on the field, and a pilot even got out of his Citation to take a picture while they were mowing,” laughs Durbin.

Interestingly, the futuristic mowing bots play a key role in the airport’s wildlife management program because keeping grass trimmed removes and/or helps disrupt food sources for the 140 species of wildlife at the airfield, which include alligators, hogs and birds of prey. As such, mowing and clearing overgrowth accounts for a significant amount of the maintenance staff’s time.

A swarm of bees also proved to be a problem when it took up residence on the wing of an aircraft. “We had to call a maintenance guy to remove a fairing on a trailing edge,” Durbin recalls. The airport also brought in a local “bee wrangler” to remove the bees, and then established an apiary to draw them away from aircraft, hangars and other buildings. (Check out the Oct. 2022 issue of Airport Improvement for the article that inspired the project.)

In a poignant example of technology and nature working side by side, the airport uses its new autonomous mowers in the area where the apiary was established. “We have to set the mowers when the bees are dormant,” Durbin notes. “Our apiary manager also mows in a bee suit.”

Culture Change

City leaders support Durbin’s move to leverage high-tech equipment at the airport.

“From our perspective, the airport really jump-started innovation in our city and they have been a shining star that has inspired other departments to try their own new ideas,” says Owens.

That influence may be spreading to other airports as well. In late February, Miami Homestead General Aviation Airport (X51) held a demonstration of three autonomous units from Honda mowing grass and spraying pesticides. The event marked the end of a three-month pilot program to test the equipment at the 960-acre airfield. Prototypes of two different models, a work vehicle and a mower, operated four days a week after being programmed with autonomous navigation and obstacle avoidance technology.

Back in Sugar Land, Rosenbaum relishes the city’s new culture that promotes innovation. “It’s not just the autonomous mowers, it’s using technology to help us be more efficient,” she remarks. “It took six years, and it’s just the beginning for us.”

Kubista, of RC Mowers, commends SGR for facing the challenges associated with turf management. “They are very innovative,” he says. “It’s not a mower thing; it’s not a technology thing. It’s about solving a labor problem.”

For Durbin, it came down to diligence and collaboration with his team, airport administration and the city of Sugar Land. “If you look at the whole journey, the city went through a transition in leadership. The new culture was breaking the status quo. Without the support of leadership, we would not have been able to do this,” he reflects.

Durbin also credits SGR maintenance workers (shown right) for embracing the new technology. “They are learning everything…and revising the mowing plans. They are truly behind the success,” he emphasizes.

With the mowing robots in service for a few months, Durbin and his crews are steadily refining mowing plans to create more efficiency and free up time to tackle the rest of the “non-autonomous” airfield maintenance tasks.

Crews mow 400 acres weekly.