Listeners Ask, Why Does DTW Have Those Giant Fans?

WDET’s CuriosiD series looks into the large, jet engine-like fans passengers encounter in a tunnel en route to the McNamara Terminal.

CuriosiD is a regular series where listeners pose questions to the WDET staff, who then investigate the answers. See past posts here.

Listeners Michelle Lundquist and Jim Fracassa were total strangers with the same question. They both asked WDET:

What are those large fans, in the tunnel, under the runway, at Detroit Metro Airport, on the way to the McNamara terminal used for?    

Laura Herberg/WDET

Short Answer

The fans were intended to push out noxious gases and smoke, in the event of an emergency. But they are not required and have apparently never been used. The Wayne County Airport Authority, Wayne County and the company that designed the tunnel were unable to explain why, then, the fans were installed in the first place. This year, the Wayne County Airport Authority will decide whether they should give the unused fans a tune up or get rid of them. But if our listeners’ suggestion sticks, they might be turned into a public art project.

Click on the audio player above to hear WDET’s Laura Herberg take listeners Michelle Lundquist and Jim Fracassa on a quest for an answer to their question.

Laura Herberg/WDET

Laura Herberg/WDET

The North Tunnel

If you’ve flown out of Detroit on Delta then you’ve been to the McNamara Terminal. On the airport grounds, on the way to the terminal, the road dips down into a tunnel under a runway. Hanging from the ceiling are large barrel-shaped fans, with propellers that resemble jet engines.

In 1997, this tunnel, named “The North Tunnel,” was constructed to connect future airport travelers to the McNamara Terminal, which would open five years later. The fans were installed with this tunnel.

“The original intent of the fans was to clear any sort of emissions that may be detected,” says Kelly Ferencz, deputy director of planning and design construction for the Wayne County Airport Authority.

According to a report from 2000, the fans were installed to push out carbon monoxide (CO) from cars, nitrogen dioxide (NO2), and methane that might be present since part of the tunnel is underground. The fans were installed to keep these gases from piling up in the tunnel.

“Everyone knows you’re not supposed to operate your car in a closed garage because the gases and nasty stuff from your engine build up. Well, the same thing can happen in a tunnel even though you’re driving through it,” explains Michael Feuser, chief engineer, tunnel and metro at Twin City Fan (Clarage). The company specializes in the kind of fans found at Detroit Metro Airport, though they did not install the fans there.

In addition to pushing out dangerous gases, jet propeller fans are also used to blow out smoke in the event of fire emergencies like the 1949 Holland Tunnel fire that happened under the Hudson River between New York and New Jersey.

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Never Been Used

So, back to the fans at Detroit Metro Airport. They are there to ensure people are protected from fumes and smoke.

But they’re not being used.

Ferencz says the fans at Detroit Metro Airport have “never been used as originally designed.” The airport authority doesn’t turn them on. And they don’t monitor air quality in the tunnel. That may sound like a very bad thing, but it might not be a big deal.

A spokesperson with the Wayne County Airport Authority wrote in an email that an evaluation of the tunnel completed in 2009 concluded that “the length of the tunnel (approximately 890 ft.) is such that natural ventilation without use of the fans is sufficient.” In other words, they found that the tunnel is short enough that it doesn’t need fans.

WDET reviewed recommended guidelines for tunnel ventilation put out by the National Fire Protection Agency and while ventilation is recommended for tunnels of this size and use, the guidelines did not specify that ventilation needed to come from forced air.

So… why are they here?

So, why are there fans in this tunnel, if the airport says they’re unnecessary? This is apparently a question the Authority can’t answer. 

“It was under the County’s direction at the time and we don’t’ have any documents to show why they were installed,” says Ferencz.

Detroit Free Press

Detroit Metro Airport used to be operated directly by Wayne County. But in the early 2000s the airport faced state and federal investigations into alleged mismanagement. About a month after the McNamara Terminal opened in 2002, a state law was signed to create the Wayne County Airport Authority.

While Airport officials said they did not have knowledge of the tunnel from before the Authority took over, a spokesperson did say that the tunnel was designed by what was then a Detroit-based firm known as Parsons Brinkerhoff. 

According to a 2009 Crains Detroit article, Parsons Brinckerhoff worked on the reconstruction of the Blue Water Bridge plaza in Port Huron, the Rosa Parks Transit Center, and it designed the Detroit-Windsor Tunnel. A Detroit Free Press article from October 9, 2005 showed the firm as a top financial backer of Kwame Kilpatrick’s re-election campaign for Detroit mayor. While Kilpatrick is currently serving a prison sentence for racketeering, WDET has no information showing that Parsons Brinkerhoff was ever involved in any foul play. Parsons Brinkerhoff is now a part of a Montreal-based company known as WSP. WSP did not return phone calls for this story.

Wayne County, which was in charge of the airport at the time the North Tunnel was built, says records for that era are mostly stored in paper files. The county was unable to retrieve information about why unnecessary fans would be installed at the airport, in time for this story’s deadline. The county also could not tell us how much the fans cost.

To get a ballpark estimate of the sticker price, WDET described the fans to Michael Feuser, the chief engineer at Tunnel and Metro for Twin City Fan. He estimates the fans would cost, at minimum, $20,000 – $70,000 a piece, (in today’s dollars). But, he says, some tunnel fans cost as much as $250,000. There are at least 36 fans installed at the airport.

The fans’ future

“We’re currently working on our 2019 inspection of them,” says Airport Authority Project Manager Ethan Futlon. He says the authority is assessing the fans to decide if it should give them a tune up and start using them or remove them.

One of the listeners who asked this CuriosiD question has an idea. Michelle Lundquist suggests with a laugh, “You could paint them and make them decoration and it’ll be a piece of art.” After all, that’s what Lundquist thought the fans were in the first place. Her fellow question asker, Jim Fracassa, had guessed that the fans were used to push out fumes.

About the Listeners

Laura Herberg/WDET

Jim Fracassa

Jim is a lifelong Detroiter, born and raised on the east side. He’s worked for more than 30 years in multimedia and event production. Jim currently lives in the Detroit neighborhood of Green Acres with his wife of 23 years and his 11-year-old son.

Michelle Lundquist

Harrison Township resident Michelle Lundquist has been practicing law for 17 years, focusing on bankruptcy, student loan issues and criminal law. Her husband is also a lawyer and they work together. In her free time, Michelle enjoys running her dog “Katie” through agility training, the popular canine sport of getting dogs to go through a variety of obstacles like tires, teeter-totters and tunnels.

Have a question for CurioisiD? Ask us here.


  • Laura Herberg
    Laura Herberg is a Reporter for 101.9 WDET, telling the stories about people inhabiting the Detroit region and the issues that affect us here.