The Golden Horseshoe, whose name is derived from the region’s historical wealth and prosperity and the characteristic horseshoe shape, is one of the most populous regions in southern Ontario, Canada. It boasts more than seven million, nearly 60 percent of Canada’s entire population and is home to Air Canada, the world’s 11th largest airline.
Headquartered in Montreal, Air Canada spearheaded the implementation of a country-wide ADF environmental program and is the only carrier to have glycol blending systems in Canada.
SAFETY COMES FIRST
Why is so much attention paid to deicing? One reason — safety. Since 1968, at least 10 takeoff accidents in North America have been attributed to wing surface ice contaminations. “NASA’s research has shown that as little as 0.8 of a millimeter of ice on the upper wing surface can knock 25 percent off an airplane’s lift and increase the drag,” says Roy Rasmussen, head of the ground deicing program at the National Center for Atmospheric Research (NCAR) in Boulder, CO.
To ensure safety, removing snow and ice from aircraft is an everyday part of airport winter operations and large quantities of propylene glycol and ethylene glycol based products are used to deice the aircraft. However, due to runoff and toxicity concerns, regulatory agencies such as the Environmental Protection Agency (EPA) and the Canadian Environmental Protection Act have set guidelines for exceedence levels. In Canada, glycol runoff cannot exceed 100 milligrams per liter.
Glycol recovery and recycling processes began in the early to mid 1990s. But it’s only been in the last two and a half years that Air Canada has been working closely with Aircraft Deicing Solutions (ADS) in conjunction with Inland Technologies to set up both stationary and mobile glycol blending stations to not only increase environmental protection but to significantly reduce costs. “Deicing is a tough area to save money because it’s directly related to safety,” says Bruce Johnstone, manager of ground safety and winter operations for Air Canada. “However, in this case, we were able to save money without compromising safety.”
CONCENTRATING, BLENDING AND SAVING
The volume of chemicals used can have significant impacts on the surrounding environment, which is why Air Canada led the execution of a country-wide program for the collection and recycling of glycol effluent three years ago.
“Air Canada and the other Canadian carriers have a contract with Inland Technologies to collect and recycle all the waste chemicals at eight of our largest stations,” says Johnstone. “In a typical year, we can collect over 30 million liters of effluent, which would have an absolute huge environmental impact if left alone.”
Of course a fundamental concern for the airlines is cost. And one of the most expensive aspects of the deicing business has been shipping glycol, primarily due to the wonted 50/50 blend. Historically, Air Canada purchased a “ready-to-use” deicing product from Dow Chemical known as XL54. XL54 contains 45 percent water and 54 percent ethylene glycol, the freeze point suppressant chemical used to remove snow and ice from the wings and leading edges of the aircraft. “As a ready-to-use product, XL-54 covers us for the worse case scenario weather conditions — down to minus 33 degrees Centigrade,” says Johnstone. “Luckily for us, even in the great white north, there are relatively few days where this level of temperature protection is needed.”
Considerable savings are available by purchasing unadulterated glycol and blending it on site, thus reducing transportation costs and storage requirements. A unit called the GlycolPro™ takes a concentrated or “neat” deicing fluid product and mixes it with water based on the temperature and weather requirements at the time of flight operations. “This is a significant departure from the way things have happened in the past,” says Johnstone. “By purchasing a neat ADF and blending it on site, we’re able to save money on transportation, storage, chemical purchases and environmental clean up.”
Under the Canadian Environmental Protection Act Part IV (CEPA), a Glycol Guideline of 100 mg/L was established. Since then, airports and airlines have worked to minimize Aircraft Deicing Fluid (ADF...
UCAR™ Aircraft Deicing Fluids are available from The Dow Chemical Company for use in preparing commercial and general aviation aircraft for winter takeoff. Products include UCAR ADF ethylene...