Its holding in flight can be severely altered

Frost is one of major risks to the safety of the aircraft. It is indeed the many accidents around the world. In January 2007, a Fokker 100 Regional company, a subsidiary of Air France, thus breached its take-off, the departure of Pau, victim of a problem of icing.

The main risk is on the ground, where the moisture deposited on the body may turn into ice as soon as the temperature is zero degrees. Hence the need Asperger the apparatus of an antifreeze product before each take-off.

In flight, even if the temperature at 10,000 meters of altitude is usually close 50 degrees, the low humidity of the air prevents the formation of frost, except if the aircraft passes through a wetland area, such as a high-altitude cloud. Several types of icing are to fear:

On the wings and on the more exposed parts that are leading edge, which can alter the aerodynamic profile and add the device. Its holding in flight can be severely altered.

Icing can also disrupt, harden, or even stuck command organs, starting with the elevator, wingtip. Thus, in the classical case of accumulation of ice on the upper part of the wing and rudder, the aerodynamic profile of the aircraft it will be amended with effect to cause the aircraft to prick, forcing the pilot to "who" to try to restore the aircraft attitude, time for the instruments of defrosting to their office.

On the different short probes that provide different calculators data necessary for the control of the aircraft. Positioned in the longitudinal axis of the aircraft, these probes come in the form of small static air intakes to measure the pressure of outside air, and of small tubes of about 30 centimetres long, known as "Pitot tubes", to measure the pressure of the air (the apparent wind). These key data are needed to determine the speed of the aircraft and adjust the engine power. If these ports are to be capped by the Frost, embedded systems are more able to set the proper procedure. They will then disconnect to allow the driver set himself the good flight parameters, which is not simple.

Frost can also accumulate in the inputs to the reactors, to be transformed into pieces of ice that could be pumped by the engine, with the risk of damage or cause a loss of power.

Like what can be observed on the panes of a window, Frost can also brutally obscure cockpit canopy.

To avoid these phenomena, all devices are equipped with relatively simple and theoretically efficient de-icing systems. Namely electrical resistance in Pitot tubes and a circuit of hot air, from the reactors, the exposed portions, such as the edges of the wings and the reactor entries. This air heated to 80 degrees can however be used permanently, under penalty of deteriorate Aerostructure parts. Finally, the driver may be required to descend quickly to get out of the zone of icing.

The safer to avoid Frost, is to avoid crossing the cloud formations that can trigger such phenomena. To do this, the pilots have weather information collected prior to the flight and refreshed by the centre ground control, but also two radar onboard, located in the nose of the aircraft. These radars can detect storm formations over 160 miles nautical (296 km) and with a maximum of accuracy from 80 miles nautical (148 kilometres), leaving the captain can change its route.

The latest radar, on including the last Boeing 777 and the Airbus A380, also to simultaneously detect the disturbance around the unit, as well as being an overview.

Ideally, the procedure recommends not to less than 15 nautical miles (27 kilometers) of a thunderstorm cell. But in practice, the flight may not always completely avoid stormy zone. In the Equatorial band, where cumulonimbus are almost permanent, pilots strive to slip between the clouds.