To the delight of pilots, passengers and others in the aviation industry, deicing technology has progressed significantly since the early days of knocking accumulation off the wings with brooms.
Along with improved techniques, fluids and equipment, the method of forced air deicing has continued to evolve.
Lee Williams – president at Avia Enviro, has been on the forefront of forced air technology, working with others in the industry to improve this deicing process. As a result, third generation technology is now patent-pending and taking the final steps towards production.
“This is the beginning of a more powerful, more adaptable system,” Williams says.
Forced Air Advancements
Williams began working on forced air deicing technology in 1983 while employed at FMC (now JBT), and continued his work later at Trump and eventually at his own company, Avia Enviro.
When the EPA came out with a hazardous material ruling on deicing fluid (diethylene glycol) in the late 1980s, Williams felt there was an opportunity to address the issue by reducing its usage.
“I had some contacts and had seen, in my travels, some systems that the Air Force had built,” Williams says, recalling the first generation of forced air deicing as simply a hot air blast. “We could see the potential in this. Even back then, in its infancy, I could see the potential.”
Rudy Yates, president of Ground Support Specialists, was working for FedEx at the time, and also saw potential in the emerging technology.
Williams and Yates collaborated on a prototype for second generation forced air technology that incorporated fluid injection.
Williams also partnered with Dr. Keith Numbers, a senior aerospace engineer for the Aeronautical Science Division of the Air Force Research Laboratory, to make improvements to the second generation equipment.
Throughout the duration of a nine-year research agreement, Numbers and Williams made notable upgrades to the nozzle and the compressed air source. Global Ground Support, among other GSE companies acquired the rights from Williams to use the nozzle and began manufacturing improved forced air deicing units.
“We kept coming up with more efficient and better ways to build the forced air unit with smaller components,” Yates recalls, noting there were several rounds of testing with Numbers’ nozzle design.
The second generation technology was designed to be a proactive approach to deicing, but Williams observed it being used in a reactive manner in the field.
At the time, Europe was putting thickened fluid on the wing, Williams says. Then, after snow fell on the wing, pilots would use a take-off roll down the runaway. At 80 knots the fluid would shear and the ice would blow off the wing prior to take-off.
“The FAA prohibits you from beginning a take-off roll with anything on the wing,” Williams notes. “So we knew that the European methodology wouldn’t be allowed here.
“So we figured that we would develop a machine – and we got specifications for all the thickened fluids to see what it took to shear those, as far as wind speed and air and so forth, and we developed the machine that’s out there now to shear that fluid,” Williams continues. “The specification was set by Dr. Numbers and me because that’s what it takes to shear Type 2 fluid off the wing the same as running down the runway.”
Although the second generation technology was designed to remove snow after using thickened fluid, many users operated the forced air deicers similarly to traditional deicers. Williams and Numbers took note of this and adapted the latest technology, accordingly.
“The design that he and I now have is the actual design to be used for the way they’re using it,” says Williams, adding the third generation unit is designed to blow coverage off the wing, when it’s actually adhered to it. “We misjudged how the industry was going to be using thickened fluid.”
Technological Improvements
According to Williams, the third generation forced air deicing technology offers significant enhancements.
While the second generation system had an upgraded nozzle and air source, both were fixed. The new system, however, features an adjustable nozzle and air source.
This feature provides better “knock-off” power and usability in different weather conditions.
“We have these operators out there, at the end of these booms, trying to deice these aircraft in all kinds of different weather conditions,” Williams says. “The weather is never the same twice, they say. Yet, we send these guys out there with very few tools to do the job.”
What’s more, the fluid injection capabilities are also adjustable.
“If we want to penetrate ice that’s frozen on the wing, we can put fluid injection into a supersonic beam and shoot right through the ice,” Williams explains. “When the fluid hits the wing down below, it spreads out underneath the ice.”
These adjustments are made by the operator, similar to how the second generation technology works.
For example, an operator may address the aircraft, and observe what looks like dry snow. The operator could attempt to remove the snow with forced air and no fluid. If there is little movement, the operator can increase the air velocity. And if the snow is much heavier the expected, the operator can, in turn, add thin or thickened fluid to the air stream.
“What this allows the operator to do is to feather in the air and fluid only to what’s needed. Instead of seeing a hoarfrost on the airplane and spraying 65 gallons a minute on it, which is way overkill,” Williams explains. “This system will allow the operator to address the aircraft with the minimum fluid necessary to get the job done.”
Williams notes the latest generation technology can treat composite materials as well. Forced air replaces the need to spray hot fluids onto cold wings during a quick turnaround, which can cause structural issues for composites.
Forced Air Benefits
According to Williams, reach and effectiveness are the two issues that have kept forced air deicing technology from being more popular.
“We identified that and have addressed both,” Williams says. “The distance that you can shoot air through air is relative to the diameter of the air stream that you begin with. If you start with a bigger diameter, it takes longer for the still air to peel away all the moving air. That’s how you can control reach.
“Even with fluid injected, air doesn’t have the same mechanical power as a liquid,” he adds. “Effectiveness has been considerably improved because we have a larger diameter.”
With a smaller amount of fluid needed to deice aircraft, forced air deicing offers several benefits.
“Before forced air, all we had was heated fluid,” Williams recalls. “It got to the point where we were spraying mass quantities of this heated fluid.”
That prompted EPA’s hazardous material ruling.
“Instead of spraying between 40 and 60 gallons a minute to clean an aircraft, you can spray a reduced amount – especially with forced air – of 7 to 11 gallons per minute, and you’re still cleaning the aircraft,” Yates, of GSS, explains.
“A forced air deicer is an expensive option. To recover the expense, you have to use it to reduce your fluid usage – which in turn, doesn’t take long to pay for forced air deicing.”
Yates says few drawbacks have been realized while testing the forced air deicing technology, mainly because several experienced people had a hand in its creation.
“The evolution process on that kind of eliminated the problem because they had done their homework,” he says. “The air simply cleans, and with fluid injection it cleans better.”
Yates points to reduced glycol use as an immediate benefit, given the cost of the fluid. Plus, less waste is better for a ground handling operation’s bottom line.
“To me, it makes very good sense,” Yates says. “One of the biggest issues I’ve seen throughout the years is getting the operators to believe in it, rely on it and trust it.”
Williams agrees, adding some have been hesitant to adopt forced air because they are familiar with traditional fluid methods and don’t feel compelled to change.
Training programs for forced air can help overcome that issue, Yates says. However, a station needs to perform regular deicing for a change to make sense.
“The stations that deice three, four or five times a year, it’s hard to justify the cost of a forced air deicer. But the ones that deice three, four or five times a week, they can certainly justify it,” Yates notes, adding commercial operations with large aircraft and heavy traffic volumes stand to benefit the most.
Both Williams and Yates view forced air deicing technology as another tool that can help ground handlers perform their job.
“Air is the free and clean medium that will transport the appropriate fluid to the aircraft,” Williams says.
“It’s a good technology,” Yates agrees. “It works. It’s proven.”
