Airport of the Month - Project Spotlight

Wadena - Crosswind runway

 

December 1, 2020

Photo courtesy of Jim Groebner of SEH

"Aerial of the new turf runway at Wadena Municipal Airport. It will be green next summer."

Lots of general aviation airports have only one runway. Some have two, and a few busy ones near urban areas might have three or even four. In many cases, the runway configuration is historic. Airports developed in the 1940s generally tried to come close to the three-runway configuration idealized by military bases built during World War II. The runways formed a triangle, assuring that aircraft could always take off and land into the wind or nearly so.

Wadena's original airport came close to the ideal. It had two turf runways so crosswinds weren't much of an issue. However, expansion of the old site proved challenging. After much study, the new Wadena Municipal Airport opened in 1998 about three miles west of town. It's a great facility with a 4000-foot-long runway, full parallel taxiway and lots of parking space. But it was missing the second runway. Long term planning for the new facility included a turf "crosswind" runway, but that was omitted from the initial development.


Construction completed this year finally got the situation correct. The new 2100-foot-long turf runway will open as soon as the grass is growing in 2021. So, who decides if an airport needs a crosswind runway? Why did Wadena wait so long? Are events determined by an omnipotent airport deity or maybe a lottery?

If there is an airport god, it's the Federal Aviation Administration. The FAA has published a bible of many books on just about every possible aviation subject. Advisory Circular 150/5300-13 is appropriately titled "Airport Design." It says that aircraft with approach speeds below 121 knots and wing spans of less than 49 feet can safely take off and land with crosswind components up to 10.5 knots. A nautical mile is about 15% more than a statute mile, and knots are nautical miles per hour so 10.5 knots is about 12 mph. It's probably obvious to most pilots that smaller airplanes with slower landing speeds are less capable in crosswinds, but that's not addressed by this "book." Airplanes with approach speeds below 121 knots include everything from brand new King Airs to classic Champs.

An appendix of the circular has instructions on how to analyze the wind at a given location. It says that 95% wind coverage is "desired," and two runways may be needed to meet that criteria. At Wadena aircraft commonly using the airport fit the 121 knots/49-foot criteria so the crosswind component should not exceed 10.5 knots more than 5% of the time. The problem is wind is a variable therefore the data changes. The FAA recommends using wind data for the previous 10 years, so what was true in 1998 might be different in 2010. This is how it went in Wadena. A once needed runway was later not justified, but still later became a recommended facility.


A recent update of the wind analysis indicated that a second runway was now desirable at Wadena, but there are other criteria and priorities for federal funds. It looked like Wadena would wait some more. Though not exactly wining a lottery, the Office of Aeronautics at MnDOT decided the turf runway was consistent with the objectives of the State Airport System Plan (SASP) and stepped in to help fund the project. The new runway cost about $550,000 with the state contributing 75% of the total.

A turf runway built in the 21st century is not just a strip of rolled grass like they were 70 years ago. Geometry of the runway is also defined in the advisory circular including cross slopes to keep the surface dry, ditches to take the water away and longitudinal grades that are friendly to aircraft. Wadena now has a turf runway built exactly to FAA standards.

Paul Sailer's books are not as pervasive as the FAA's, but the Wadena resident writes about the experience of Minnesotans in World War II. Titled "The Oranges Are Sweet," his biography of Hill City native Major Don Beerbower earned Paul the Minnesota Aviation Hall of Fame "Writer of the Year" award for 2012. Beerbower flew P-51s and was the top scoring fighter pilot of the U.S. Army's 9th Air Force. Unfortunately, he was killed in action shortly after D-Day. Sailer was an Army helicopter pilot in Vietnam and writes with authority about combat flying.


With the new runway landing at Wadena will be easier than ever. Leave the King Air home and come in your Champ to sample the new grass. You can celebrate by buying a copy of Paul Sailer's classic about a Minnesota aviator who's truly an American hero.

 

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