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Five Fast Facts on Icing and Deicing

By MR. MATTHEW LIPTAK, Staff Writer

“I was saying to one of the new guys who was in the bucket with me earlier, it’s kind of like playing a video game,” Senior Airman Ian Bartlett, Aircraft Maintenance Squadron Crew Chief said. “You are shooting the liquid at a plane ... It’s kind of fun.”

That deicing liquid is part of the routine maintenance of prepping an airplane to fly in freezing conditions. Maybe you are a flyer who has gone through this routine before, or maybe you have just been a passenger. Whatever the case, icing is something that needs to be addressed for safe flight to happen in the colder months, and it can be mitigated with the deicing process.

Here are some facts about icing that you may not be aware of:

  1. Icing adds weight to the aircraft, which is problematic for several reasons. Ice increases drag and decreases lift; that will definitely affect flight performance. Vibration can occur on rotors and propellers as a result of the ice, too, which can require more power to maintain flight. If ice builds up on the outside of the aircraft, brakes and landing gear may not function properly, radio communication may be lost, false instrument readings may occur, and outside vision will probably be reduced or may be completely lost.
  2. One type of aircraft icing is structural. Structural icing is icing that collects on the structure of the aircraft when surface and air temperatures are at or below freezing. Clouds are the most prevalent type of water in the air. Freezing rain is the other most likely visible form of moisture that can cause icing. Precipitation is the most dangerous of all the different icing conditions because of the speed at which it can build up and the difficulty of removing it.
  3. Three subcategories of structural icing are clear, rime, and mixed. Clear ice is the most dangerous. It is hard and shiny, and it is very difficult to remove with deicing equipment. Clear ice is found most often where you find high moisture content in the clouds and temperatures slightly below freezing. It adheres to the aircraft’s surfaces and can build to a dangerous level in a short time. Rime ice is milky and granular in appearance, making it more brittle and easier to remove than clear ice. It is made up of small water droplets that freeze when they strike the surface of the aircraft, and a lot of air usually gets trapped in with the water. It is not as heavy as clear ice, either, so its weight is less of an issue. Mixed ice is a mix of small and large water droplets, sometimes with snow or ice particles mixed in. It builds rapidly, and ice particles can become embedded in clear ice, making a rough surface.
  4. Induction icing can materialize in the air induction systems, by which air is taken into the engines. It may also condense in the fuel systems under a wide range of weather conditions, and it can affect the entire power plant. Carburetor icing is a subcategory within induction icing that is extremely dangerous and often results in total engine failure. This type of icing forms during fuel vaporization combined with the expansion of air as it passes through the carburetor. It can also form when temperatures are above freezing. Be aware that this might happen, and keep on the lookout.
  5. In 2015, a deicing simulator was introduced. The simulator helps Airmen learn and train on deicing procedures without actually using the equipment. The simulator resembles a video game, with controls that are an exact replica of the controls in the deicing cab. “It helps students with muscle memory,” said TSgt Chris Runge, 92d Maintenance Group (MXG) Development Element Noncommissioned Officer in Charge (NCOIC). “It allows them to get to a level they wouldn’t normally get to in a short time period.”

As always, safety is a precursor to all flights, whether you’re in temperatures above freezing or below. The Air Force is particularly aware of the dangers of icing and is exacting when it comes to mitigating these potentially unsafe conditions. Icing can be a challenge to safe flight, but corrective action can be taken.

 ”The Air Force policy is that pilots will not take off with ice, snow, or frost adhering to the wings, control surfaces, engine inlets, or other critical surfaces of the aircraft. Tests have proven that ice, snow, or frost formations having a thickness and surface roughness similar to medium or coarse sandpaper on the leading edge and upper surface of a wing can reduce lift up to 30 percent and increase drag up to 40 percent,” said TSgt David Lamb, 92d MXG Maintenance Qualification Training Program (MQTP) instructor. “If anything is left on the plane, it can interfere with the aircraft’s lift and be potentially dangerous.”