What is the risk of using expired de-icing fluid?

Using expired de-icing fluid significantly reduces its effectiveness, which can create serious safety hazards. De-icing fluids are specifically formulated to perform optimally within a certain timeframe, and once they expire, their chemical properties may degrade. This degradation can lead to lower freezing point depression and a diminished ability to remove or prevent ice accumulation on aircraft surfaces. As a result, the aircraft may not achieve the necessary level of safety and performance needed for takeoff and flight, especially in conditions where ice formation is possible. Therefore, using expired de-icing fluid poses serious risks not just to the operation of the aircraft, but also to the safety of its passengers and crew.