SIOUX FALLS, S.D. (KELO) — Is the airspace around the Sioux Falls Regional Airport Joe Foss Field getting too crowded?

The number of flights to and from the airport continues to grow. Data available from the state and other sources show that plane registration and flights are also steady, if not increasing in eastern South Dakota.

Sioux Falls is classified by the Federal Aviation Administration (FAA) as a Class D airspace. In 2022, the airport had a total of about 1.2 million enplanements and deplanements or 611,933 enplanements and 615,828 deplanements. That is about a total of 3,300 enplanements and deplanements a day.

Devin Bastemeyer, the director of the aviation program at South Dakota State University, said airspace can be described as an “upside down wedding cake.” The rings are the layers of the cake with the smallest layer as the airport and control tower. Class A involves 18,000 feet mean sea level up to and including 60,000 feet and is mainly for high performance aircraft. Class B is for very large airports such as Los Angeles, Denver and similar-sized cities. Class C is used by airports such as Omaha.

The purpose of airspace designation and flight rules is to prevent aircraft from getting to close to each other in the sky and from runway incursions. In 2020, there were 220 pilot-reported near midair collisions in the U.S., according to the U.S. Department of Transportation Statistics. The number is low considering that on average each day, FAA’s air traffic control provides service to more than 45,000 flights and 2.9 million airline passengers across more than 29 million square miles of airspace, according to the FAA. The yearly passenger count for 2020 was down because of COVID-19 to 369 million passengers that year, according to the FAA.

A Class D airspace has a radius of 4.4 nautical miles or about five miles by road. In comparison, Class C airspace is five nautical mile radius with an outer radius of 10 nautical miles.

If an aircraft wants to enter the Class D airspace assigned to the Sioux Falls airport, it must communicate with the airport’s air traffic control tower, Bastemeyer said.

“Each time you fly into controlled air space, you need to check in with traffic control,” said Emma Duncan, a communications official with the FAA.

But if a plane is leaving or landing at the airport in Tea in Lincoln County, for example, there is no notification to Sioux Falls required because the airport is outside of the Class D airspace.

Dan Letellier, the executive director of the Sioux Falls Regional Airport, said the airport has sought a change to a Class C designation. Class C has an wider airspace than a Class D. The airport in Tea, for example, is about seven to eight miles from the airport in Sioux Falls, he said.

FAA airspace classification chart.

“If it were Class C, radio tower coverage would include Tea,” Letellier said. “Anyone arriving or departing from Tea would need to talk to the tower.”

That would be a good requirement because planes flying to and from Tea don’t always show up on radar because of the low altitude, Letellier said.

Dale Knuth of Hartford is the president of the South Dakota Pilots Association. Although pilots are not required to contact the tower in Sioux Falls with arrivals or departures at smaller airports, “that doesn’t mean we are not listening,” Knuth said.

Pilots will use radio communications to monitor air traffic in the area. Planes are also equipped with other navigation and monitoring tools or pilots use iPads or similar to monitor air traffic, he said.

“It’s not like we are flying blind,” Knuth said.

Bastemeyer and flight instructor Brody Bates at SDSU said pilots, including their students, monitor air traffic communication as Knuth said.

The SDSU representatives also said pilots, including their students, will make a common courtesy call to airports if they are flying near an airport’s air space.

“You don’t just want them to see some random airplane coming by…,” Bates said.

There are two sets of rules for flying aircraft: visual flight rules (VFR) and instrument flight rules (IFR).

Aircraft using VFR means planes can be flown under specific visual requirements.

Pilots can file a flight plan with a VFR flight but the FAA does not require them to do so. If a pilot files a flight plan, they would be communicating with an air traffic control tower.

If a pilot is on a flight using instruments (IFR), they are required to submit a flight plan and communicate with the air traffic control tower.

While the number of flights to and from Sioux Falls has increased over the years, and the airports near Sioux Falls such as Watertown continue to have flights, aircraft also use smaller airports such as Tea and Madison.

Ten years ago, city and airport officials projected growth at the airport in a 2013 airport master plan. The chart below shows that the 2013 projections were not far off as in 2022, there were 611,933 enplanements.

According to AircraftOne, there are 2,010 registered aircraft in the state. There are at least 300 registered planes in Minnehaha and Lincoln counties.

Jack Dokken, the air, rail and transit program manager for the South Dakota Department of Transportation, works with grants and other funding for airport projects in the state. Based on the interest in the SD DOT programs, airport use is healthy across the state, Dokken said.

Can a Class D become a Class C airport?

There are specifications for each class of airspace. Airports need to meet the criteria and a FAA evaluation to be classified.

Duncan said there is a process to change an airspace designation that includes applying for an evaluation by the FAA. The airport and the local control tower typically request the application, she said.

Letellier said the local tower manager had compiled information for a request from Sioux Falls.

In 2013-2014, the FAA did a study of the airport and concluded it did not meet the qualifications for Class C airspace, Letellier said.

According to the FAA, this is the criteria to be considered a candidate for Class C airspace designation:

  1. The airport must be serviced by an operational airport traffic control tower and a radar approach control; and
  2. One of the following applies:
    • An annual instrument operations count of 75,000 at the primary airport.
    • An annual instrument operations count of 100,000 at the primary and secondary airports.
    • An annual count of 250,000 enplaned passengers at the primary airport.
    • Class C designation contributes to the efficiency and safety of operations and is necessary to correct a current situation or problem that cannot be solved without a Class C designation.