With average snow accumulations of 4 1/2 feet per winter, snow removal is serious business at Minneapolis-St. Paul International Airport (MSP). Crews plow, blow, broom and deice more than 28 million square feet in airfield pavement alone - the equivalent of a two-lane highway running from the Twin Cities to New Orleans.
Project: Snow & Ice Removal
Location: Minneapolis-St.Paul Int'l Airport
Airfield Maintenance Staff: 110 (primarily equipment operators & mechanics)
Airfield Pavement Maintained:
Approx. 28 million sq. ft.
Equipment Fleet: 21 runway plow trucks; 15 front-mount rotary brooms; 8 multifunction vehicles; 18 snow-blower trucks; 19 sanding trucks; 8 deicer trucks; 15 gate tractors; 25 wheeled loaders; 12 skid-steers
Avg. Snow & Ice Events: 40/season
Deicer Products: New Deal Sodium Formate/Acetate Blend; Cryotech NAAC & Liquid Deicers
Materials Used/Season: 240,000 gal of liquid deicer; 65 tons of solid deicer; 7,000 tons of sand
Recognitions: 6 Balchen/Post Awards for Outstanding Achievement in Airport Snow & Ice Control (1982, 1986, 1991, 1992, 1997 & 2001)
Equipment Supplier: MacQueen Equipment Group
Plow Trucks: Oshkosh Corp.
Plows: Wausau Everest; Little Falls Machine; Frink; Degelman
Front-Mount Rotary Brooms: Oshkosh Corp.
Brooms: M-B Companies
Runway Deicers: Tyler; Batts; Hagie; Epoke
Wheeled Tractors: John Deere
Wheel Loaders: Caterpillar
Sand Trucks: Sterling Ford; Freightliner
Sand Spreaders: Swenson
Snow Blowers: Oshkosh Corp.; R.P.M. Tech; Provonost
Multifunction Vehicles: Oshkosh Corp.
Skid Steers: Bobcat; ASV
Snow Melters: Trecan Combustion
How serious is serious? The Metropolitan Airports Commission (MAC), which operates MSP, has invested about $55 million in snow removal and deicing equipment for the airport. Costs associated with snow removal (excluding equipment repairs and personnel expenses) account for fully 82% of MSP's total airfield maintenance budget.
Crews operate a fleet of more than 140 pieces of equipment. And in an average winter, they apply 240,000 gallons of liquid deicer, 65 tons of solid deicer and 7,000 tons of sand. But the centerpiece of MSP's war against the white stuff is less tangible than equipment or materials yet equally important: a snow-removal "playbook" designed to avoid or minimize flight delays and diversions.
The airport already had procedures in place for 30- and 60-minute runway closures. But two years ago, field maintenance workers told management they could do better. So they literally went to a chalkboard and diagrammed "plays" and timed various strategies to determine what could be accomplished within various time increments. As a result, MSP now can implement twice as many closure options for the airport's three primary runways, depending on how much time is available, Sichko reports.
The result? A perfect batting average for the last two years, reports Paul Sichko, assistant director of operations, maintenance and airside operations. "We haven't missed or had to extend a coordinated runway opening time during a snow event."
Last year, the airport served more than 33 million passengers, with nearly 413,000 takeoffs and landings.
To fully understand MSP's playbook, it's helpful to understand the resources MSP deploys to handle the 40 "snow events" it faces during an average winter. The airport's field maintenance department includes 110 full-time employees: 76 maintenance workers and heavy-equipment operators, 20 repair shop personnel and 14 administrative staffers.
In addition to snow removal, field maintenance workers also perform surface repairs, maintain parking ramps, repair security gates and fencing, and manage the airport's turf and landscaping. "The field maintenance staff is essentially a public works department with year-round duties," notes Sichko.
Given the harsh winters, snow removal accounts for much of their time. "With the exception of leased space, MAC employees conduct all airside snow removal operations, including snow removal from aircraft parking gates, at both terminals," he details. "MAC also is responsible for snow removal along airport-owned public roadways, while sub-contractors remove snow from parking ramps and surface parking lots."
During winter, the airport augments its staff with an additional 16 maintenance workers and laborers who log 40-hour weeks for 22 weeks. MSP retains another 40 heavy-equipment operators on a temporary basis for day-of-storm work, adds Sichko.
Crews use a large fleet of equipment to clear roughly 6 million square feet of runway, 9.7 million square feet of taxiways, 10.3 million square feet of ramps and 2.4 million square feet of deicing pads. The fleet includes 21 runway plow trucks, 15 front-mount rotary brooms, eight multifunction vehicles, 18 snowblower trucks, 19 sanding trucks, eight deicer trucks, 15 gate tractors, 25 wheeled loaders and 12 skid-steers.
Unlike many airports, MSP does not run a 12-hours-on, 12-hours-off schedule during snow events. Instead, it takes an all-hands-on-deck approach, which means there could be as many as 108 employees working at a time. As such, MSP provides room-and-board perks during snowstorms, with sleeping quarters for up to 300 people, shower and locker room facilities, and a full commercial kitchen - all in the airport maintenance building.
MSP's playbook enables large contingents of crewmembers and equipment to work in concert, explains Sichko. To maximize readiness, workers rehearse various "plays" numerous times, with dry runs during non-winter months.
"The best analogy is a football play," he says. "We call the play and pick the option we want to execute. We'll have up to 23 vehicles on the (main) runway, and they all know exactly what to do and how much time they have to do it.
"And we don't audible," he adds. "We don't pull an Aaron Rodgers and change the play at the line of scrimmage."
After two years of development and refinement, MSP's playbook contains numerous strategies for a range of weather and traffic scenarios. "For our largest runway (about 10,000 feet long, with roughly 2 million square feet of pavement), we can do a 60-minute full closure, which is usually done overnight and involves clearing exit points to all 21 connecting taxiways," Sichko explains. "Then we have a 30-minute closure that provides 14 runway exit points; a 20-minute closure that provides about six exit points; and a 10-minute closure in which we clean only the runway - a straight shot with only entrance and exit points."
Crews use different snow removal methods for different parts of the airport. On runways, where speed counts, plows form a wing (also known as a conga-line formation) to clear most of the snow. Then rotary brooms clean down to the pavement, snow blowers clear windrows, deicers apply potassium acetate and trucks spread sand, in that order.
At terminal gates and ramps, and on the airport's 53 acres of deicing pads, plays focus on volume. For ramps, crews use tractors to push snow away from the building toward the rear of aircraft at gates, where front-end loaders with box plows move it to holding areas.
Snow collected airside is temporarily stored on grass islands adjacent to runways and taxiways until it can be hauled to designated storage areas. Sometimes snow melts in the storage areas; usually, it has to be taken to in-ground tanks that use 40° water and agitation to melt the snow. Trios of melters powered by natural gas (with a total capacity of 120 tons per hour) are located at eight different airside locations. Eight 40-ton-per-hour melters are located in and around the airport's six major parking structures. In addition, the airport has a portable 60-ton-per-hour melter that's used airside and landside as needed. In total, the airport has 33 snow melters at its disposal.
Snow that doesn't go to the melters can last a surprisingly long time. "A couple years ago, we still had snow piles here in July," relates Sichko.
Coordination & Communication
Executing a runway closure at MSP involves communicating with no less than seven other organizations and agencies: The Metropolitan Airports Commission; MSP air traffic control tower; Minneapolis Terminal Radar Approach Control (TRACON); Minneapolis En route Center (part of the network of regional Air Route Traffic Control Centers run by the FAA); Delta Air Lines (the airport's largest carrier); Delta-MSP gate control; and Delta's operations control center in Atlanta.
"All these parties come together on a conference call to coordinate every closure," Sichko explains. "We assess how many airplanes are in the air and determine how much time we have to plow. Our goal always is to avoid diversions to other airports."
The cost of delays is also a factor. The FAA estimates that on average, delays cost airlines roughly $75 per minute per airplane.
But it's also about safety, emphasizes Scott Schulte, an MSP maintenance worker who operates snow removal machines. With 30,000-pound vehicles driving up to 26 mph just 30 feet apart in a wing formation, there's little margin for error, he points out.
"There's no freelancing allowed, because collisions can occur if someone is in an area they're not supposed to be in," Schulte explains. "During our snow removal operations, the runways are the safest places at the airport, because we know exactly where every piece of equipment is at all times. That's important, because visibility often is limited ... maybe down to as little as 50 or 100 feet with all that snow kicking up in the air."
Sichko cites advanced equipment and strategically located deicing pads as two important factors that enhance MSP's ability to execute its playbook.
Thanks to hydraulic technology, snow removal machines now operate faster and move more snow in critical situations when time is tight, says Dan Gage, co-owner of MacQueen Equipment Group, which supplies the Metropolitan Airports Commission with snow removal equipment. Gage highlights the ribbons on snow blowers as an example: "Today, snow blowers offer six different speeds ... if the truck goes 35 miles per hour, the ribbon can turn at 35 miles per hour.
"Years ago, we only had single-speed blowers, which were much slower ... so if you pushed too fast, the blower's capacity couldn't match the speed, and you ended up with a lot of snow blowing past the blower," he continues. "But multiple-speed blower heads allow you to match blower speed with the travel speed of the vehicle."
Brooms now rotate faster, too - up to 575 rpms compared to 300 a decade ago. That enables the trucks they're mounted on to go faster without sacrificing efficiency, he explains.
The advent of multifunctional vehicles - trucks that carry a plow on the front while towing a broom - has also reduced removal times. "You have much more flexibility now in attacking various levels of snowstorms," Gage relates.
MSP has six deicing pads that collect and contain the deicing fluid that airlines or contractors spray on aircraft. In total, the pads can accommodate 37 aircraft simultaneously.
"They're all located at the end of runways and were specially constructed to capture the deicing fluid, which contains glycol - a substance we want to keep out of storm drains," Sichko explains. "We do allow airlines to deice planes at the gates. But in that case, we plug the storm sewers and pump out the deicing fluid later."
He points to the pads' large capacity as a key factor in keeping airplanes moving during winter storms. "And because the deicing pads are located away from the terminal buildings, we don't clog our gates (with airplanes getting deiced)," he adds.
"We've never deiced 37 all planes at one time, but the end-of-runway deicing pad volume is critical to our success," he points out. "We learned years ago that the inbound rate of airport arrivals cannot exceed the outbound deicing rate. If only 20 planes can be deiced per hour, and we land 40, simple math tells you we'll have airplanes everywhere on the field - and that just doesn't work."
What does work, however, is the teamwork and collaboration between MSP's management and maintenance crews, Sichko and Schulte agree.
"Our management team has come up through the ranks," Schulte observes. "All the managers understand the capabilities of the crews and our equipment, which fosters a relationship of trust and respect and a real sense of team spirit. We get excited about a big snowstorm. We think of ourselves as snow fighters."
"It's always better if you can get creative and find better ways of doing things," Sichko adds. "And that's exactly what this team does."
As for the future, Sichko and Schulte say that the snow removal playbook is a work in progress that's constantly evolving. Could 15- and 25-minute closures be possible?
"There's always room for improvement, especially as new (more productive) equipment emerges," Schulte says. "Eventually, we'd like to have eight plays in the playbook for each runway ... we're working on it."