Behind-the-scenes look at United Airlines' de-icing operations at O'Hare

CHICAGO (WLS) -- Despite the sunny skies, bitter cold makes aircraft safety more challenging - especially de-icing operations at O'Hare International Airport. But the pros prepare especially for days like today, when keeping airframes free of snow and slush requires skills honed over a lifetime.

ABC7 got an exclusive tour on the tarmac and in the control tower with United Airlines de-icers.

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In the middle of the O'Hare sits the CDF, or Central De-icing Facility, a nerve center for the last operation aircraft undergo before takeoff.

Between them, Chris Pearson and Jay Lampe have 60 years of experience making sure deadly snow and ice find no home on the leading edges of aircraft that make Bernoulli's principle of lift work. The orange propylene glycol water mixture goes on first, and then the green stuff - the same compound, but at room temperature.

"That actually protects the wings and the tail section from snow re-adhering to critical surfaces of the aircraft," Pearson said.

You may have seen the mist over the wings as you looked out the window while taking off. Before the pandemic, United was pushing out as many as 675 departures a day. Now that number is about a third less, but always there's a wary eye cast to contaminants.

"We have aircraft leaving here to a short taxi out time, less than five minutes sometimes," Lampe said. "It is a lot safer atmosphere in heavy snowfall conditions. They are wheels up within 15 minutes. Holdover times are never compromised at that point."

The deicing fluid comes out of about 140 degrees to ensure ice does not form on all the leading edges of the airplane. If you're in a plane and you're coming all the way out here, it actually makes your trip a lot more efficient because you can get out of the gate faster and on your way.

Depending on the wind, planes take off and land generally headed east or west bound. Today is a westward day, which means a lot of planes are coming in over Lake Michigan, so they're picking up moisture and the possibility of ice. When they land, they have to get airborne again quickly, so it's up to these crews to ensure that last measure of safety - even if that means a little more time spent on the tarmac.

"Be patient, it's worth the ride," Lampe said.