Skip to page content

Performance Success Stories

NextGen Tool Helps Aircraft Stay the Course

A NextGen air traffic control alerting tool is helping to reduce the effects of go-arounds at Minneapolis-St. Paul International Airport:
  • There are 23 percent fewer go-arounds
  • Total excess time flown due to a go-around is 19 percent lower
  • The time between go-around events has increased from 12.3 days to 21.3 days
Automated Terminal Proximity Alert reduces the number of go-arounds at airports. It is cutting miles off your route.

NextGen Implementation Plan (PDF)

Separation Management
Provides controllers with tools to manage aircraft in a mixed environment of varying navigation equipment and wake performance capabilities.

The careful choreography that air traffic controllers apply to simultaneously keep 5,000 aircraft flying safely in U.S. skies is amazing to behold. Now, NextGen technology is giving controllers one more shot in the arm to make it all run more smoothly: a new software tool called Automated Terminal Proximity Alert. As a passenger, all you need to know is that it's cutting miles off your route. Does getting to the airport a few minutes sooner sound like a good idea to you?

Everyone knows the drill. Checking your watch and looking out the window, you know you'll be landing soon. Then you realize the plane is turning away and circling back around. The safety maneuver, used to create more space between planes, carries costs in time, fuel and stress.

Now, NextGen is helping to reduce these go-arounds. During its first year of use, the number of go-arounds declined by 23 percent for flights headed to Minneapolis-St. Paul International Airport. Automated Terminal Proximity Alert (ATPA), decreased the excess flight time due to a go-around by 19 percent. And, by using this tool, the average number of days between go-arounds issued to provide the minimum required space between aircraft on their final approach to the airport has increased from 12.3 days to 21.3 days.

"This makes us safer and more efficient," said Glen Hansmann, operations manager at the Minneapolis Terminal Radar Approach Control (TRACON) facility, which directs aircraft in the airspace surrounding the airport. "Controllers have better awareness of gaps. They can adjust plane speed or give the plane a short 'S' turn instead of taking them all the way out."

First implemented at Minneapolis in May 2011 and now deployed at TRACONs around the country, this tool adds visual information to screens controllers already use. It is optional, but controllers find it so useful that nearly all of them use it, Hansmann said.

Triangles displayed between aircraft on the controllers' radar screens show the minimum required separation distance for planes lining up to land, which is 3 - 10 miles depending on the aircraft type. An additional line shows a continuous mileage-readout between aircraft, accurate to 100th of a mile. If ATPA projects that the trailing aircraft may come too close, the mileage-readout display changes color to alert the controller. This gives the controller time to adjust the aircraft's speed without having to send them back around.

Without this tool, controllers have to rely on their eyes when looking at their screens to determine safe separation. "The ability of the human eye to distinguish between 2.9 or 3.1 miles is not possible," said Mark McMillen, support manager for Minneapolis Tower and TRACON. "A numerical reading increases the controllers' accuracy and therefore increases the safety and efficiency of the operation."

Training to use the tool is built into regular controller training, McMillen said. An updated version will add in separation needed for planes approaching parallel runways, he said.

Page last modified:

This page was originally published at: