Southwest likely hasn’t seen the last of a proposal to install Performance-Based Navigation (PBN) at the Minneapolis-St. Paul International Airport, which could concentrate planes departing over Southwest into about three major flight paths.
“The FAA [Federal Aviation Administration] really has a say in what we’re going to do,” said Dan Boivin, chair of the Metropolitan Airports Commission (MAC). “This will continue to be an issue.”
On Nov. 19, MAC voted against PBN implementation in Southwest Minneapolis, responding to loud protests from Southwest and Edina residents. MAC recommended only partial PBN implementation over Eagan and other east metro suburbs.
Boivin said he’s not sure what the FAA will think of that idea. He expects the FAA to respond in the next couple of months, perhaps accepting the compromise, deciding against it, or delaying the decision.
The new flight paths would usher planes over the same blocks every day, rather than scatter departure routes across the city. The heaviest paths in Southwest would fly over Highway 62; a northwest route located south of 50th Street through Windom, Kenny, Armatage and a corner of Fulton; and a northwest route over Cedar Lake that cuts between Lake of the Isles and Lake Calhoun, crossing through portions of Kingfield, East Harriet, East Calhoun, CARAG, Kenwood and Cedar-Isles-Dean.
Boivin said the agency could override MAC and require PBN over the entire metro area.
“The FAA controls safety in air space,” he said. “They do what’s best for safety. … It’s the FAA who is going to draw the line.”
Not long ago, the airport had a major safety scare over South Minneapolis. In September 2010, a small cargo plane and an Airbus with 90 passengers took off from different runways at the same time. The control tower instructed the Airbus to turn left and head west, accidentally crossing the other plane’s path. The planes were in the clouds and neither pilot saw the other, but the Airbus captain could hear the other plane passing. They came within 50-100 feet of vertical separation, approximately 1,500 feet above the ground, a mile-and-a-half from the runway.
Following the incident, planes now use runways based on the direction they are ultimately headed, so they won’t again have the chance to accidentally intersect.
Boivin said safety is a benefit of PBN, although safety was only part of the reason MAC is considering the switch.
“PBN was inevitable,” Boivin said. “The airline industry wants to go to it, and the FAA wants to go to it.”
Other benefits of PBN include fuel economy and simpler communication with air traffic controllers. Noise relief is also considered a potential benefit — MAC’s Noise Oversight Committee started studying PBN in 2007 to reduce the aircraft noise impact around the airport. The precise, predictable flight paths can route planes over less-populated areas, such as the Minnesota River Valley in Eagan.
Former FAA Administrator Marion Blakey has characterized the system as “green technology.”
“It flat out saves fuel,” Blakey said in a May 2007 Airport Noise Report. “It relieves congestion, alleviates choke points, and reduces delay. It increases efficiency by providing smoother traffic flow. It’s clear that performance-based navigation is good for the environment. Flying straight down the middle of a flight path means that people on the ground perceive less jet noise and experience fewer jet emissions.”
The big picture
City Council members say PBN should be part of a larger conversation about the airport’s potential expansion.
“We need to look at this more holistically,” said Council Member John Quincy (11th Ward).
MAC is considering the relocation of all non-Delta airlines to Terminal 2 (Humphrey), expanding both terminals and adding new and expanded parking ramps. Air traffic could grow from 435,583 flights in 2010 to a projected 484,879 flights in 2020. An additional 350 city blocks would require noise mitigation, according to the city of Minneapolis, which is an area larger than all of the Minneapolis lakes combined.
MAC has conducted an environmental assessment to study the impact of an expansion, but the City Council has requested a more in-depth environmental impact statement.
MAC’s current assessment does not adequately address air pollution, Quincy said. The state is close to its maximum allowance for fine particulates, he said, and if the airport nudged pollution out of compliance with clean air standards, it would be very expensive to fix the problem.
The City Council has also objected to the airport’s method of determining which homes receive noise mitigation. MAC relies on noise maps that average the decibels over a 24-hour period.
“Noise isn’t experienced in 24-hour averages, but instead as individual events,” Quincy wrote in a recent newsletter.
If the airport did move to a PBN system, homes underneath the new flight highways are not projected to see a substantial increase in noise, based on MAC’s projections, and therefore would not immediately receive noise mitigation investments. Dana Nelson, MAC’s noise and operations analysis coordinator, said the change is projected at 1 or 2 decibels, an amount that is not audible to the human ear. She noted that MAC follows FAA standards to create its noise contour maps.
“If you’re under the departure paths, you’re going to hear an increase [in noise],” she said. “The maps don’t really paint that picture.”
Looking ahead, it seems likely that Southwest residents will provide input on future plans.
Fulton resident Sara Thompson said she hopes to see an advisory committee emerge so that residents can stay engaged in the airport’s direction.
“It’s been getting noisier and noisier,” Thompson said. “Everyone needs to work together to find a good solution.”