Different European airports they remained closed temporarily due towave of cold and frost which affected parts of central and eastern Europe: among these also the airport of Viennaone of the busiest on the continent, as well as those of Budapest (Hungary), Bratislava (Slovakia) and some airports in France and the United Kingdom.
But why can’t planes fly in ice? As also reported by ENAV (the company that manages civil air traffic in Italy), the problem is mainly due to the fact that the ice risks alter the aerodynamic properties of the aircraft. In particular, the presence of ice on the wings disturbs the flow of air, compromising lift (the lifting force that keeps planes in flight), but it can also cause an increase in the weight of the plane, therefore increasing its drag and tending to slow down the plane due to friction.
At the same time, ice compromises the slope safetymaking landing, taxiing and take-off maneuvers more dangerous.
Airports closed due to cold waves and snow: the problems caused by ice
The main problem is that ice generates different effects on the aircraft, influencing its aerodynamic flow. Specifically, ice can accumulate:
- On the wings: in this case, it disturbs the airflow and the wing gets less lift.
- In the propellers (if present): in this way, the plane decreases its thrust.
- On the tail of the plane, reducing the ability to maintain the aircraft in level flight.
- On intake filters and supply air intakes, where it reduces the air flow needed by the engines, decreasing the power output.
- On some control surfaces such as flaps, which can impede movement, making it difficult for pilots to control the direction in which the plane flies.
- Anywhere else on the plane: In this case, the ice adds weight to the plane and increases its drag, tending to slow it down due to friction.
It should also be considered that ice could also form on the airport runwayswith the risk that the plane slips off the path or, worse, fails to slow down sufficiently during the landing phase. Added to all this is the fact that ice, often, is connected to adverse weather conditionswhich limit visibility and make these maneuvers more difficult, while the accumulation of ice on the antennas can create disturbances to radio communications and signal reception.
What airports are doing to solve the problem
But, then, how do planes fly during the winter season, especially in colder countries? Through the de-icing: this is a standard procedure for defrosting and antifreezing, which is done to remove ice already present on the wings and also limit its formation during flight at altitude.
The first phase is that of actual de-icing and consists of spraying a special blend composed of hot water (at approximately 65°C) e antifreeze liquid (usually propylene glycol) to remove existing snow and ice. The second, however, is that ofanti-icing: in this case, the antifreeze is not diluted in water and this allows a denser layer to form on the wings than avoids the formation of ice at altitude.
Pilots, however, check the weather forecast before each flight to decide the route to follow, therefore determining whether to cancel or delay a flight due to weather conditions.
