Airport Of The Month – Duluth International

In 1929 the city of Duluth purchased 640 acres to build an airport. It opened in 1930 with two, 2,650-foot-long turf runways. Scheduled airline service to Duluth started in 1940. After the beginning of World War II, three paved runways were constructed in the classic "triangle" of that era. Each was 4,000 feet long.

Runways 9/27 and 3/21 were extended to 5,700 feet in 1945. Runway 9/27 was later extended twice, reaching the current length of 10,151 feet in 1956. Runway 13/31 was closed in 1973 due to an airline terminal expansion.

Duluth International Airport (DLH) has long been shared by civilian and military traffic. Military aircraft based in Duluth once included the North American F-51 (formerly P-51) of World War II fame and later the F-106 which at one time held the absolute world speed record.

F-16s of the Minnesota Air National Guard are currently based at DLH. Two major airlines provide scheduled passenger service and one does seasonal charter flights. Over 80 civilian aircraft call DLH home and Cirrus Aircraft manufactures light airplanes there as well.

In 2016, the concrete pavement on Runway 9/27 had just celebrated its 60th birthday and needed reconstruction in a bad way. There were also significant geometry problems that the FAA wanted fixed.

It would seem all you need to replace 200,000 square yards of runway is a lot of money, but that's a bad assumption.

Most of the traffic could operate on Runway 3/21 temporarily, but F-16s need more than 5,700 feet. At some point, the runway intersection would have to be closed, and the taxiway system had to remain in operation. The Duluth Airport Authority (DAA) needed to do some careful planning.

The solution was an elegantly designed three-phase construction plan that fit just about everyone's needs. The new pavement is 13 inches of Portland Cement Concrete (PCC). Incidentally, 24 miles of Interstate Highway could be paved with the materials needed for the 2-mile long runway. So you can build some highway and drive 24 miles, or have a runway and go anywhere in the world.

First the middle 6,200 feet was completed. This avoided the intersection, allowing Runway 3/21 to remain fully operational. Phase 1 of construction was done while F-16s were deployed or temporarily stationed elsewhere. The remainder was divided into two phases, the west end going first with the threshold displaced.

This gave the construction crew a spectacular view of airliners and fighters taking off and landing over their heads. Lastly, the east end was reconstructed, with the end of Runway 27 moved to the west for the duration. Phase 3 included reconstructing portions of Runway 3/21 that are within the 9/27 safety area so the main runway can remain fully useable when the second runway is eventually resurfaced. The last phase also addressed the FAA concerns.

While they were at it, the DAA installed 500 new lights and 40-plus miles of electrical cable. Updated airfield signage was installed and a modern system for controlling all the lighting replaced the older stuff. It looks like Runway 9/27 at the Duluth International Airport should be good for another 60 years.

Ever wonder why U.S. Air Force fighters have tail hooks since they don't fly from aircraft carriers? Runways at fighter bases have arresting gear that's the last resort for stopping the aircraft in the event of an emergency like brake failure. Runway 9/27 at Duluth has that and it too was upgraded as part of the project. Tail hooks on the F-16s are also used to hold back the fighter during full power engine runups.

When the F-106s at DLH were defending the USA, the plan was to guide them to Russian bombers using something called "Semi-Automatic Ground Environment" or SAGE. One of the 22 SAGE sites was in Duluth and received radar data from as far north as the Arctic Circle. It's the good fortune of the human race that SAGE was never needed for the intended purpose. The system was manufactured by IBM and each site had 60,000 vacuum tubes (that's enough for 10,000 TV sets of the era). Youngsters may wonder, "What the heck is a vacuum tube?" but that's what made computers possible back then. The weight of each unit exceeded 200 tons and could be replaced by a few 21st century laptops or maybe a box of smart phones.