Flight In Known Icing


Basics of the aircraft deice and anti-ice systems

Icing is one of the mostly daily occurrences of line flying. Since it’s often unavoidable, aircraft are equipped for flight into known icing conditions. That is to say, the aircraft has been tested and certified for flight into areas where icing conditions are known to exist. Since the day that mail began flying instead of riding the rails, the business goal has been to have a consistent and reliable schedule. The ability to fly into known icing is a critical component of scheduled service.

With most turbine aircraft, hot compressed air is drawn from the engine into an elaborate ducting system that leads the hot air to wing leading edges as well as engine nacelle lips and the horizontal stabilizer. This air is dubbed “bleed” air as it is “bled” from the engine core. Turbine aircraft often have many uses for this bleed air: pressurization, air conditioning, engine starting, and anti-icing.

When required, this extremely hot air can be tapped from the engine core and led to critical flight surfaces for anti-icing and deicing requirements. This can generally be done either manually or via automatic activation. Ice detector probes are designed in such a way that icing will form first on the probe. This probe is designed to vibrate at a specific frequency and when ice has accreted on its surface, that frequency of vibration changes. The system recognizes the ice buildup and, depending on the configuration of the system, it activates the anti-icing system. You can manually activate the system without the use of the detector probes.

During winter operations it’s often required that aircraft be deiced before takeoff. Remember you should never attempt to take off with snow, frost, or ice crystals adhering to the aircraft. The entire aircraft should be clean of contamination prior to takeoff—not just the control surfaces, or the wings and tail. This protects the aircraft during takeoff and initial climb. It can often be a two-part process: deicing the aircraft to remove contaminants, then a coating of anti-icing fluid. The latter is almost always required when freezing conditions are present and there is precipitation.

Combining the ice protection systems and the deicing and anti-icing technologies, we are able to provide safe and comfortable transport through the most inhospitable conditions.