Older methods to direct air traffic in the metro area largely depend on navigational aids on the ground or radar by air traffic controllers, according to the Federal Aviation Administration.
Area navigation, or RNAV, can put pilots on more direct routes, generally through satellite technology. It requires less communication between air traffic control and pilots and makes for more efficient use of airspace, according to the agency. RNAV changes have been part of NextGen, a set of updates the FAA is making in the Denver area and around the nation.
The Metroplex plan is another part of the NextGen updates. It aims to make further changes with new flight paths for airports in metro areas like Denver.
The airports affected are Centennial Airport, Rocky Mountain Metropolitan Airport in the Broomfield area, Denver International Airport, Northern Colorado Regional Airport in Loveland and Greeley-Weld County Airport.
From Nov. 18 through Dec. 20, the public was able to comment on any of the changes made between the draft environmental assessment of the plan and the final environmental assessment.
Changes between the draft study and final study are listed here.
The rest of the documents related to the plan are available here. The link labeled "final EA full document" still goes to the draft, but the one above it lists changes made in the final study.
The FAA held 12 public meetings, mostly in the Denver metro area, at which FAA representatives answered questions about the project and took written comments. Those ran from April 29 to May 16, 2019.
After that, the agency took comments online and by physical mail during a roughly six-week public comment period, which lasted until June 6, about the April 22 draft EA.
The FAA sent out an announcement of the project in May 2016. Public comment was initially accepted through early June 2016, according to the notice.
The agency hosted 12 public workshops to explain the project and take comments between April and May 2017. It also fielded online comments for a month afterward.
Developments surrounding the FAA's Metroplex plan since early last year:
• Mayors in Englewood, Littleton and beyond in the Denver metro area raised concerns about new flight paths: South metro Denver area braces for potential flight-path changes
• The FAA's draft of the study on Metroplex says the plan will have "no significant impact" on the metro-area noise, air quality, wildlife, and historic and cultural resources: Metroplex flight-path impact portrayed as minor by feds
• At one of the FAA's public meetings, the agency says the notable changes in flight paths will only involve about eight flights per day: Noise impact of altered flight paths to be mostly small, FAA says
• Centennial Airport writes a letter to the FAA, saying its plan would put planes in "volatile conditions" and that the agency did not properly study its environmental effects: Centennial Airport says FAA left gaps in flight path study
• Centennial Airport files legal action against the FAA in federal court, pushing for a further look at what the plan's effects could be: Centennial Airport taking FAA to court over flight paths
• Centennial Airport pulls its legal action on a technicality but plans to bring it again: Centennial Airport legal action against FAA over flight plans delayed
• The FAA's final version of its study on the Metroplex plan upholds the determination that the plan will not have significant impacts — meaning further review isn’t necessary before the plan is put into action: Final Denver Metroplex flight-path study upholds planned changes
• As the FAA announced the Metroplex plan would be implemented in March, Centennial Airport and the agency continued to disagree over whether the FAA considered noise impacts for the part of flight that occurs closest to the ground: FAA gives final green light to Denver Metroplex flight-path changes
Just before the federal government implemented a plan in March to reroute airplane traffic in the Denver metro area, Centennial Airport and local governments filed legal action asking a court to review a study of the plan’s potential impact on noise and the environment.
The Federal Aviation Administration’s plan to optimize arrival and departure at local airports is called the Denver Metroplex project, and it includes Denver International Airport, Centennial Airport and some others.
An FAA environmental-assessment study looked at impacts the project could have on noise, air quality, wildlife, and historic and cultural resources.
It said the proposed change in flight paths is expected to have “no significant impacts” on those aspects of the project’s area, including metro Denver and the Greeley area.
The FAA released an official final word — a “finding of no significant impact” and “record of decision” — which enabled the agency to move forward with the Metroplex project. The decision was announced Jan. 24.
The finding means the FAA determined that a further review, called an environmental impact statement, isn’t necessary before the plan is put into action, according to the FAA’s website.
Despite the court challenge, the project went into effect as scheduled on March 26, according to Centennial Airport, after nearly four years since the FAA put the plan in motion. But local officials in the south Denver metro area and beyond are hoping to pump the brakes.
Centennial Airport; the boards of commissioners of Arapahoe, Douglas and Gilpin counties; and the City of Greenwood Village filed legal action in the U.S. Court of Appeals for the District of Columbia Circuit in March, a few days before the plan’s implementation date. It’s the latest outcry in years of complaints local officials have raised about the plan.
The legal action seeks to address whether “the FAA’s finding of no significant impact in its environmental assessment was arbitrary and capricious” and whether the agency’s process violated federal environmental policy, according to an April 23 filing in the case.
It also asks the court for review of the FAA’s determination that an environmental impact statement isn’t needed.
While the plan would directly impact only a handful of airports, potential effects could be felt in an area that includes all, or portions of, 31 counties in Colorado — although the FAA’s analysis indicates only a few dozen people would experience notable noise increases, located in unincorporated Jefferson County and unincorporated Elbert County.
“The FAA’s environmental review for the project indicates some people will experience slight noise decreases, some will see no changes and some will experience small noise increases,” the FAA said in a news release.
Centennial Airport has argued at length that the FAA didn’t consider the impact of flight that occurs below 3,000 feet above ground, and that leaves unclear how much communities could be affected by the planned changes.
Littleton, Centennial, Cherry Hills Village, Lone Tree, Castle Rock and other nearby cities could experience effects, but it’s unknown how much, Robert Olislagers, executive director of Centennial Airport, has said.
“As has been stated before, the FAA completely ignores impacts below 3,000 (feet above ground), which makes any noise modeling deeply flawed,” the airport wrote in a Dec. 18 letter to the FAA.
That means the final part of flight wasn’t adequately analyzed by the agency, the airport argued in a separate letter to the FAA.
But Kenitzer, the FAA spokesman, said in December that noise modeling was done in the environmental assessment for the portion of flight that occurs below 3,000 feet above ground for all proposed paths in the Metroplex plan, and said that includes the final portion of flight.
It remains unclear what explains the discrepancy between the airport’s and FAA’s statements.
“We respectfully disagree with the FAA,” Olislagers said in January. The airport intends to address the point in court, according to Deborah Grigsby Smith, airport spokeswoman.
A filing in the case argues the FAA’s movement of a flight path south at the request of a Boulder County citizen increased negative impacts on Gilpin County and was arbitrary and capricious.
The case also argues the FAA failed to involve Gilpin County, including the county’s board of commissioners, its Historic Preservation Advisory Commission and its citizens, in outreach about the plan. It also said the FAA failed to include county officials and the county’s historic preservation body in consultation required under the National Historic Preservation Act.
By the time the Metroplex project went into effect on March 26, the coronavirus pandemic had altered the commercial and the general aviation landscape, said Olislagers, Centennial Airport's director.
The COVID-19 crisis caused massive reductions in flights by as much as 90%, Olislagers said. That made it impossible to assess the impact of the project’s new flight paths.
“The coronavirus basically upended that for the time being since there will be no good baseline comparison at this time between pre- and post-Metroplex implementation impacts,” Olislagers said.
When “we see a return to normal, those impacts will become much clearer, and the expectation is that any relevant evidence will be presented in court.”
The action is a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit, filed March 20 by the Arapahoe County Public Airport Authority — the government body that oversees the airport — and Greenwood Village, Gilpin County and Mountain Aviation Inc., a charter and owner-operated aircraft services company headquartered at Rocky Mountain Metropolitan Airport in the Broomfield area.
Arapahoe and Douglas counties filed a separate petition for review March 23, and the two petitions were consolidated into one case.
Initially, Centennial Airport had filed a petition for review June 19 but later withdrew its case because the filing was premature, and the court formally dismissed the case Aug. 16. The new petition bears no difference from the airport’s side of the case, according to Grigsby Smith, the airport spokeswoman.
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