AIR ANTIFREEZE
THE NEXT TIME you board an airplane in a snowstorm to escape our frigid winter for a warmer climate, consider what it takes sometimes to prevent that snow from bringing down the plane.
Frost, ice, snow? Hundreds of litres of de-icing and anti-icing fluid prepare each aircraft for takeoff. Photographer Phil Carpenter looks behind the scenes at Trudeau airport.
Each aircraft, depending on size and other factors, needs to be bathed in hundreds of litres of de-icing fluid to melt snow, ice or frost, or to repel any freezing precipitation before it takes off.
Ethylene glycol is the main ingredient in this antifreeze. And even though most of it can be collected after use, and treated before disposal, glycol can still have an adverse impact on the environment.
That’s why AéroMag 2000, which operates the de-icing facility at Montreal’s Pierre Elliott Trudeau International Airport, plans to treat and recycle used glycol for aircraft de-icing beginning this year. The treatment of the used fluid, the first of its kind in Can- ada, is slated to start in February.
“We will be able to bring it back to an almost pure state — 99.6 or 99.7 per cent — which is required for it to be certified by a manufacturer,” AéroMag 2000 general manager Mike Hume said, adding that the Dorval airport facility will be the first in the world to return used glycol to that level of purity for use in de-icing and anti-icing.
In Canada, ethylene glycol is used instead of propylene glycol for aircraft deicing because of its low freezing point — minus-12 Celsius, and colder when mixed with water. There are two fluids used for de-icing/anti-icing operations. The first, Type 1, which is heated, is used to melt and wash off snow, ice or frost, and is mixed mainly with water.
Hume said that the water to glycol ratio depends on the temperature outdoors. “For example, from zero to minus-5 degrees Celsius we use a 25 per cent to 30 per cent glycol concentration. If the temperature drops to minus-31 degrees or so, the glycol ratio is increased to 55 per cent concentration.
The other fluid, used for anti-icing, is known as Type 4, and is not diluted. “It is applied at 100 per cent and is designed to sheer off the aircraft as it taxis for takeoff,” Hume said.
For many years, concerns have been raised about glycol runoff from de-icing operations at the airport contaminating streams and waterways in the area. That’s why, Hume pointed out, when the de-icing centre was built, the bay for each plane was sloped in order to channel the used Type 1 fluid into an underground collection system.
The Type 4 fluid isn’t recovered because it remains on the plane’s surface to repel freezing precipitation, and is blown off onto the tarmac as the plane taxies for takeoff. However, Hume said, AéroMag is able to recover about 70 per cent of all the glycol used on a plane.
But used glycol still has to be disposed of, and, the city of Montreal handles the disposal through one of its treatment centres. As for the waterways around the airport, Hume said that AéroMag conducts daily testing to monitor the glycol levels.
“We ensure that the levels stay below 100 parts per million,” which is within governmental norms.
Glycol is biodegradable but because it requires oxygen to do so, it robs that oxygen from the environment.
By law, planes must be de-iced. Under Transport Canada’s Canadian Aviation Regulations, the Clean Aircraft Concept prohibits “takeoff in an aircraft that has frost, ice or snow adhering to any of its critical surfaces such as wings and propellers.”
It was adopted by Transport Canada following recommendations by an inquiry into the 1989 crash of an Air Ontario Fokker F-28 in Dryden, Ont., in which 21 of 65 passengers and three of the four crew members perished. The cause of the tragedy: ice and snow on the wings.
Frost, ice or snow on crucial surfaces of an aircraft, such as wings, propellers and stabilizers, can have a significant impact on the operation of an aircraft, affecting it in two ways:
The additional weight of the ice or snow adds to the total weight of the aircraft, increasing the lift required for the aircraft to take off.
The formation of frost, ice or snow also changes the airflow over the wing, reducing the overall lift a wing can produce.
Also, frozen contaminants can jam control surfaces, preventing them from moving properly.
The dilemma facing airports and the aviation industry is how to balance ever-increasing flight-safety needs with mounting environmental concerns without compromising either.
AéroMag 2000 — which also operates de-icing facilities in Mirabel, St. John’s, Ottawa, Vancouver and Cleveland — hopes that by treating and recycling glycol, instead of having it disposed of, at least some of these issues will be addressed. Plus, Hume added, it’s going to cost less to recycle fluid than it is to buy it on the market. “Obviously, the project has to be viable.”
As long as our winters are cold and as long as we keep flying, it seems that there’s no getting away from using glycol. At least for now.