The Rhyme And Reason Behind Aircraft Deicing

DISCUSSION: During a typical Winter Storm, there is no question that one of the biggest stresses for world travelers are the impacts delivered to the global aviation network. First and foremost, one of the biggest threats to both private and commercial aviation threats is the inherent threat tied to both ground and in-flight icing which can unfold do to snow and ice accumulating on aircraft bodies and wings as well. The reason for why this is so hazardous to aircraft of any kind is because any accumulation of snow and/or ice can often lead to a loss of stable flight via a disruption of even, balanced airflow over the length of the wings as well as a common imbalance in the distribution of weight via ice accumulation during a given flight.

To dive deeper into this process courtesy of the How Stuff Works website, “Deicing agents are compounds made up of the chemical glycol and water. Glycol lowers the freezing point of the solvent, water. The agents are used in different formulations for different weather conditions, but whatever the formulation, the compound is applied in the same way. It is heated and sprayed through a hose over an airplane to remove snow, ice or frost. Pilots make the call for deicing when necessary and oversee the process, which must be done in accordance with detailed Federal Aviation Administration (FAA) rules. In fact, the FAA rules chapter on deicing runs more than 30 pages and covers everything from makeup and handling of the deicing compound to its application, how quickly it must be applied and the documentation required following each deicing occurrence.

Speed and thoroughness are essential in applying deicer. As such, applications must be performed in a timely and well-ordered fashion, with an eye on what’s called holdover time, the amount of time following deicing before the plane has iced-over again and must be re-treated. Holdover time varies based on the makeup of the compound and is set by the fluid manufacturer. With deicing compounds costing upwards of $5 per gallon, the procedure can cost thousands of dollars (factoring in handling and storage costs), so it’s essential that holdover times not be exceeded. Holdover time also explains why deicing is performed after everyone is on board and the plane is otherwise ready to take off. Holdover time may only be a few minutes, so the plane must be ready to taxi onto the runway and get into the air soon after deicers are applied.

Deicing agents are generally not designed to keep ice or frost from re-forming on the plane. So, if snow, sleet or freezing rain is actively falling as an airplane is being deiced, the plane may also need an anti-icing application to keep ice from re-forming before the plane takes off. Anti-icing fluids are also made up of glycol and water, but with a higher concentration of glycol than deicing fluids. A thickening agent is added to help the compound adhere to the plane as it takes off.”

Thus, this explanation just goes to show that even during the heart of the worst Winter storms which you may face in life, it is imperative to always be understanding when it comes to ground-stops which may come to reality at a given airport. Namely, since many larger airports cannot always keep up with icing both on the aircraft and the wings of aircraft both on the ground and in the air. Hence, the phrase “patience is a virtue” will often come into play during the cold days of Winter.

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© 2018 Meteorologist Jordan Rabinowitz