Neighbors battle noise, lead pollution at busy metro Denver airports

Charlene Willey checked her smartwatch as a sudden rumble enveloped her Westminster home less than half a mile from the runway’s end at Rocky Mountain Metropolitan Airport.

“That was 70 decibels inside with the doors shut,” she said, sitting at her kitchen table as the sound — nearly the equivalent of that made by a vacuum cleaner — faded as fast as it came. “That was a piston engine.”

Over the next 90 minutes, no fewer than seven airplanes roared over her roof in the Green Knolls neighborhood just east of Wadsworth Boulevard, either on approach to or takeoff from the airport.

“I swear I could spit on them, they’re so low,” said the 72-year-old retired financial services planner, who has lived in the shadow of the airport for three decades but said the noise only became irritating — and then unbearable — in the last few years.

Thirty miles away, Nathan Winger can’t find peace either. With an average of 360 daily takeoffs and landings at nearby Centennial Airport, the nation’s second-busiest general aviation airport, planes circle over his Greenwood Village home on an almost constant basis.

“It’s not unusual to have nine or 10 planes in the same flight pattern for hours on end,” he said. “There are lots of times we would put our kids down for naps and they couldn’t sleep because of the planes.”

Noise complaints, which have steadily increased in recent years around both airports, are directed largely at burgeoning flight schools, which put practicing pilots on repetitive “touch-and-go” routes over neighborhoods in loud piston-engine planes. And they fly more due to an FAA rule enacted a decade ago that boosted the required flying time to earn a pilot’s license from 250 to 1,500 hours.

Add to the overhead cacophony the fact that many of the planes chew through gallons of fuel laced with lead, the emissions of which can pose a particular hazard to young children, and households at both ends of metro Denver have reached a breaking point.

A lawsuit already has been filed by neighbors near Rocky Mountain Metropolitan Airport while another is being readied by those living close to Centennial Airport. Resident concerns have reached the highest levels of government, with members of Colorado’s congressional delegation beseeching the FAA to step in and provide relief.

Meanwhile, the airports — together they generate nearly $3 billion in economic activity annually and provide work for more than 13,000 people both on-site and in ancillary businesses — say flight paths and frequency are an FAA matter. Michael Fronapfel, Centennial Airport’s executive director, said his facility “cannot legally restrict flight traffic.”

“We share the communities’ concerns with the increase of training traffic over their homes, which is why we are pushing hard to have the FAA assign technical experts to work with the flight schools, airport and community noise roundtable to look for solutions to the problems that result from an extended training pattern,” he said.

Donna Johnston, a Greenwood Village councilwoman, said she can’t walk a block in the city without hearing from a neighbor about traffic from the airport.

“I’m not surprised people are trying to tackle this issue from all avenues,” she said. “It’s not just an annoyance — it’s ridiculous.”

Noise as a health issue

Noise may be much more than just an annoyance. It may, in fact, be downright unhealthy.

According to a New York Times investigation of the impacts of noise published last month, exposure to chronic noise — like blaring train horns, clattering traffic on a nearby highway, or yes, airplanes flying overhead — increases the risk of negative health outcomes.

Unpleasant sounds, the newspaper reported, register with the amygdala — the brain’s stress detection center — which in turn pushes the endocrine system into overdrive, flooding the body with cortisol and adrenaline. A quickened heart rate and high blood pressure often result.

“Over time, these changes can lead to inflammation, hypertension and plaque buildup in arteries, increasing the risk of heart disease, heart attacks and stroke,” The Times wrote.

Willey thinks night flights, one of which awakened her recently at 2 a.m., throw her body and mind out of whack. She felt so lousy the next day that she went to her doctor, who found her blood pressure noticeably elevated. He suggested a connection between her condition and the post-midnight flights over her neighborhood.

“I just want to make my house livable — to stop making me so sick,” Willey said.

On the other side of Rocky Mountain Metropolitan Airport, in Superior’s Rock Creek neighborhood, Noelle Roni said it’s not unusual to be awakened by overhead air traffic.

“I’ll be in bed and it will rattle our windows,” she said.

Roni has lived in the neighborhood for 19 years and doesn’t remember things being this bad until a year or so ago. She speculates that trainees have adjusted their flight paths to do turnarounds over her house. Using an app, she tracks planes from Rocky Mountain airport and on some days flight patterns can be so concentrated and overlaid they show up on her phone screen as “a thick highlighter.”

“Why are we allowing a few people to affect thousands of people, with no limits?” she asked.

Recent data show Superior at the top of Rocky Mountain’s noise complaint list. In 2022, residents of the Boulder County town made 1,865 complaints about airport activity, with people living in Westminster coming in second at 422. In total, nearly 3,000 noise complaints were filed with the airport last year, up by a factor of nearly 10 from 2016.

In late 2020, the Rock Creek Master Homeowners Association sued Jefferson County, which owns Rocky Mountain Metropolitan Airport, to vacate the avigation easements with the neighborhood’s 2,800 homes that were hammered out decades earlier. An avigation easement is a right of overflight, noise and all, in the airspace above a property.

The homeowners association alleged noise levels measured 10 times the maximum represented by the airport. A judge handed the community a partial victory in 2021, ruling that the avigation agreements had been violated over parts — but not all — of Rock Creek. The HOA appealed the decision, but the Colorado Court of Appeals last month affirmed the lower court’s ruling.

Airport director Paul Anslow said Rocky Mountain has become appreciably busier in recent years, with operations (takeoffs and landings) jumping from 170,000 in 2018 to more than 260,000 last year. Because the airport receives federal funding, he said, it must be available “for public use on reasonable terms and without unjust discrimination to all types, kinds and classes of aeronautical activities.”

“RMMA is open 24 hours a day, 7 days a week just as with our publicly-funded road system,” Anslow said.

Four fixed-wing flight schools, which generate most of the ire from neighbors, operate at the airport. Anslow said neither the FAA nor the airport, which was known as the Jefferson County Airport before changing its name to Rocky Mountain in 2006, tracks flight volumes at the schools.

Attempts by The Denver Post to reach two of the flight schools for comment were unsuccessful. The FAA did not return a request for comment for this story.

Jefferson County Commissioner Tracy Kraft-Tharp said the hierarchy over management of the skies is clear — and authority doesn’t rest with local officials.

“The FAA has jurisdiction over all airspace and people can fly where they want to fly,” she said. “An airport is like a highway — if there is a Harley-Davidson going down that road really loudly, you can’t ban all Harley-Davidsons.”

Airports here first

At Centennial Airport, more than 40,000 noise complaints have been filed over the last five years, though complaints dropped last year to fewer than 6,000 from more than twice that the year before. The increased noise prompted the formation of Quiet Skies Over Arapahoe County, a community group that claims “hundreds of touch-and-go operations (laps) are being performed by piston-engine aircraft” over homes.

“These planes fly at low altitudes creating noise and lead pollution putting our health, safety and quality of life at risk,” the organization declares on its website.

Residents say things got particularly bad after a mid-air collision of two small planes over Cherry Creek reservoir in May 2021, when they claim the FAA shifted flight school patterns over homes.

Fronapfel said operations at Centennial Airport have actually fallen in recent years, dropping from 356,000 in 2019 to 302,000 last year. But he acknowledged that certain neighborhoods north of the airport have seen an increase in impacts.

“The flight data does show that traffic over residential areas northwest of the airport has seen at least a 50% increase when compared to 2019,” he said, then added: “That traffic is managed by the tower, which is under FAA control.”

The airport, he said, is putting pressure on federal aviation officials to provide some relief for those on the ground.

Rocky Mountain Metropolitan Airport, Anslow said, has “taken proactive steps” to deal with its noise issues, including the creation of a noise task force, revision of voluntary noise-abatement procedures and continued participation in the RMMA Community Noise Roundtable.

While it’s important for the county and airport to keep peace with the neighbors, Kraft-Tharp said, the benefits of the airport are often obscured by the complaints. With pilots aging out or retiring, a looming pilot shortage faces the nation. Projections from the U.S. Bureau of Labor Statistics show that from 2020 to 2030, about 14,500 positions for airline and commercial pilots will open per year.

In June, a debate erupted in Congress over the 1,500-Hour Rule, put in place by the FAA after a plane crash near Buffalo, New York, in 2009. Lawmakers argued over whether the minimum flying time to become a pilot is too stringent and is exacerbating the nationwide pilot shortage.

“There’s a lot of pressure for regional airports to train pilots,” Kraft-Tharp said.

General aviation airports, like Rocky Mountain and Centennial, are also important economic drivers, she said. According to the 2020 Colorado Aviation Economic Impact Study by the state’s Division of Aeronautics, the economic impact generated by the state’s 74 public-use airports was nearly $50 billion annually, with just shy of 350,000 people employed by the industry and by businesses directly impacted by airports.

On-site positions include employees in airport operations and management, fixed-based operators, terminal concessions and cargo carriers, according to the report. Then there’s visitor spending by those flying into the airports, which supports jobs in hotels, restaurants, ground transportation and the retail and entertainment sectors.

Rocky Mountain Metropolitan Airport itself provides more than $730 million in economic activity a year for the region and has spurred the creation of more than 3,300 jobs on and off the airfield, the report said. At Centennial Airport, the economic yield is an annual $2.1 billion, with more than 10,300 jobs supported.

“Centennial Airport (then-Arapahoe County Airport) was developed in conjunction with the Denver Tech Center and the surrounding business parks and the airport has played a significant role in the economic development of Denver, specifically in the south end of the metropolitan area,” Fronapfel said.

Mike Boyd, an aviation consultant based in Evergreen, said it should be remembered that the two airports were here first — Rocky Mountain began operations in 1960 and Centennial debuted eight years later. The seas of houses, for the most part, came after.

“If you have a plane and it has an engine attached to it, you’re going to get noise complaints,” he said. “It’s like moving to Florida and saying, ‘I don’t like salt air.’ You knew there was an airport there when you made the down payment.”

That said, airports don’t operate in a vacuum. Boyd said they should put pressure on the FAA to work with the community to alleviate their airport-related concerns.

“They can be advocates for the neighborhoods with the FAA,” he said.

Winger, the Greenwood Village resident, concedes that Centennial Airport was there long before he was, but feels there has to be some middle ground in dealing with its impacts, especially as those impacts change in scope and location over time.

“Nothing seems to happen,” he said. “I’m not sure what else we can do.”

And thus the lawsuit, which Winger and his neighbors are trying to raise money for through a nonprofit group they just formed last month, called Safe Skies Colorado, whose stated goal is to curtail “the current uncontrolled nature of flight school activity.”

Not only will it address noise, but it will take on a quieter — but more nefarious — threat: lead.

Planes “crop dust” lead

While lead was removed from auto gasoline decades ago, there hasn’t until recently been a good lead-free way to prevent damaging knock to airplane piston engines. The result: piston-engine aircraft are now the greatest contributor to lead emissions in America, according to the Environmental Protection Agency.

It was only last September that the FAA approved an unleaded fuel for all piston engines, though it will take years for it to become the de facto aviation gasoline, known as avgas.

Lead is particularly hazardous to children and there is no accepted safe level of exposure. The EPA says lead can cause slow growth, behavior and learning problems, low IQ and hyperactivity and hearing problems in kids.

That was a chief reason why the Cherry Creek School District sent a letter to the FAA in March, expressing concerns about the pollutant’s potential effect on its 53,000 students who live around Centennial Airport. Superintendent Christopher Smith asked the agency to conduct an environmental impact study and find “a swift and sustainable solution that is suitable for everyone.”

Concern over lead is just as palpable up north. In Superior, elected leaders penned a detailed letter in April to the FAA and Jefferson County demanding that “unleaded avgas be made available at RMMA and leaded avgas be phased out from RMMA as soon as possible.”

“Recently, nine members of the Superior community had their homes tested for lead and all 18 samples, two per household, have come back positive,” the Superior trustees wrote.

That includes Rock Creek resident Roni, who said lead particles were detected on the windowsill of her teenage son’s bedroom. She dreads testing her children’s lead levels but plans to.

“We don’t open our windows anymore, which is really sad, because I love fresh air,” she said. “I’m scared to death.”

One of the most comprehensive lead studies involving airports comes from Colorado State University economics professor Sammy Zahran, who led a probe of leaded fuel combustion impacts on people living near Reid-Hillview Airport in east San Jose, California.

His team at Mountain Data Group got access to 10 years worth of blood-level lead testing from residents living under the flight paths. The study, released in the summer of 2021, found the most disturbing results for those living within a half-mile — and downwind — of the facility.

At that proximity, children had lead concentrations in line with those found in children living in Flint, Michigan, during the water contamination crisis there several years ago. Blood lead levels were 20% higher in those children than in those living between a half-mile to 1.5 miles from the airport.

In the wake of Zahran’s disturbing data, Santa Clara County announced it would no longer allow the sale of 100-octane leaded avgas — commonly known as 100 low lead, or 100LL — at both Reid-Hillview and San Martin airports. However, planes burning leaded gas obtained elsewhere can still use the airports.

Many would like to see that same conviction at Centennial and Rocky Mountain airports. In a letter to Jefferson County commissioners that was signed by three dozen metro-area doctors and nurses last summer, neonatologist Pam Gewinner decried planes that “crop dust” lead particles on homes below.

“We find it appalling that this practice has been allowed to continue despite the precedent set nearly 50 years ago by the removal of lead from paint, plumbing and automotive gasoline.” she wrote.

She told The Post in an interview that the letter was a “call to arms,” but that in the months since it was sent, it has “fallen on deaf ears.”

Anslow, Rocky Mountain Metropolitan Airport’s director, said the transition to unleaded fuel in the general aviation sector is underway but won’t be achieved overnight. One big hurdle, he said, is “the aviation and petroleum industries’ ability to scale the production of these alternative fuels to achieve a market-ready and price-competitive supply.”

The switchover needs to happen nationally to make it viable, Anslow argued. He noted that the FAA has set a target of 2030 to end leaded gasoline use in the industry through the Eliminate Aviation Gasoline Lead Emissions, or EAGLE, initiative.

“RMMA is working to secure FAA grant funding to assist both on-field fixed-base operations with the purchase of unleaded fuel tanks,” he said.

And the airport will “will provide rent incentives to the based flight schools in order to offset the cost” of fueling up lead-free, Anslow said.

Centennial Airport has made greater strides on this front, announcing recently that it is now the first airport in Colorado to offer unleaded avgas. For the month of May, the first month the Swift UL94 unleaded fuel was available, 8,373 gallons of it was sold out of 54,641 total gallons of avgas sold at the airport, giving the new formula a market share of 15%, Fronapfel said.

The airport, he said, is reimbursing the additional cost of using UL94, which is $1 a gallon higher than conventional fuel. But he said the biggest barrier to a wholesale switchover to unleaded is “the ability of the aircraft to use the fuel safely.” Only 70% of piston-engine aircraft are eligible to be certified to burn UL94 at this point, Fronapfel said.

“Currently, we have received notifications that 84 aircraft have received the Supplemental Type Certificates that allow them to use the UL94,” he said. “Of those, 69 aircraft belong to flight schools, so it is safe to say that the flight schools are on board with the transition.”

Electric planes, which would address both the noise and lead issues, are on the horizon but not here yet. The head of Bye Aerospace, which is based at Centennial Airport, told The Post last month that the company is only a couple of years away from getting its four-seat electric plane certified as a training aircraft.

In the meantime, Zahran, the CSU professor, said the fuel switch should happen sooner than later.

“I would encourage policymakers and decision-makers to weigh the benefits against the cost of transition,” he said.

“Little piece of heaven”

Several members of Colorado’s congressional delegation have spoken out on the ongoing situation at both airports, both in letters to the FAA and in speeches to Congress. In April, Rep. Jason Crow chided the FAA from the House floor, accusing it of inaction and urging it to be “more responsive to community concerns.”

My Centennial, CO neighbors have suffered under the frequent, loud noise from planes overhead. Many have said it’s virtually unlivable.

This week I called for any legislation on the @FAANews’ reauthorization to address the health, safety, & noise concerns of our community. pic.twitter.com/Dvhwtx0eQc

— Rep. Jason Crow (@RepJasonCrow) April 21, 2023

In the 2nd Congressional District, which encompasses Boulder County, Rep. Joe Neguse has pushed the Aircraft Noise Reduction Act in Congress, which would permit general aviation airports to impose restrictions related to noise without FAA approval, including limiting the number and type of aircraft that can use the runways and setting specific hours or curfews for operations.