How to prevent ice formation in flight? De-icing is the best prevention
In winter, cold temperatures can cause ice to form on the surface of aircraft wings. If the aircraft is flying in clouds containing cold water droplets, the water vapor condenses on the wings of the aircraft, it will damage the aerodynamic structure and affect the flight safety. A passenger plane of a foreign airline has appeared in an engine inhalation of ice falling off the wing, causing the engine to stop the plane crash.
Therefore, before the winter aircraft takes off, the crew will spray deicing liquid on the fuselage. The deicing liquid is generally composed of ethylene glycol, propylene glycol, etc., which is heated to 82 ° C and sprayed on the surface of the aircraft to remove the surface ice of the aircraft. At the same time, the mixture of deicing liquid and water will reduce the freezing point to -50 ° C, which can effectively prevent secondary icing. However, this deicing effect has a certain time limit, and once the time limit is exceeded, it will fail and need to be deiced again.
At present, in addition to the conventional spray deicing solution method, there are three other methods:
One is the compressed air deicing method. As the name suggests, it is the use of high pressure air to blow away the accumulation of ice on the surface of the aircraft, which is ideal for removing snow.
The second is infrared heating deicing method. This is a new deicing method, which uses a high-power infrared generator installed in a cluster to emit infrared radiation to the surface of the fuselage, heating the fuselage to melt snow and ice to achieve deicing effect. This method has an advantage - no residual pollutants on the fuselage, green environmental protection. However, the disadvantages are also very obvious, the equipment cost is large, the investment is large, and it is generally suitable for airports with long winter snow cycle and more flights.
The third is the hot water deicing method. This is a commonly used method in the past, but there are great limitations, when the aircraft remains stationary, hot water in the environment below 0 ° C will quickly cool, and re-form ice on the surface of the fuselage, affecting the normal use of aircraft moving parts and measurement and control instruments. Therefore, only after the use of hot water deicing within 3 minutes of the aircraft takes off, can play a deicing and anti-icing effect.
There are three ways for the airport to deice the aircraft, namely, the aircraft position deicing, the fixed point deicing, the local deicing.
Deicing is when the aircraft is parked in the aircraft position and the deicing vehicle is driven to the aircraft position to deice the aircraft. This method is suitable for airports with low deicing frequency;
Fixed-point deicing is a deicing platform set at a fixed point, and the aircraft travels to the deicing platform for deicing operations before takeoff. For airports with large flow, this deicing method is relatively efficient. The above two deicing methods are used to turn off the engine during the deicing process.
Local deicing is one of the most efficient methods of deicing at present. In simple terms, a deicing area is established on the taxiway where the aircraft takes off, where multiple deicing vehicles and other deicing equipment gather. When the aircraft queues on the taxiway, it will pass through the deicing area, and multiple deicing vehicles will work at the same time, and it only takes 7 to 8 minutes to complete the deicing operation of an aircraft. After deicing is complete, the aircraft can slide directly into the runway and take off. During the entire deicing process, the aircraft engine is in a slow running state, so it is called "slow deicing".
Strictly speaking: Spraying anti-icing solution before the aircraft takes off is not called "aircraft deicing", it should be "anti-icing"! Because there is no ice on the plane itself before takeoff, some solution that is not easy to freeze is sprayed, so that when the plane encounters cold water drops at high altitude, it will not freeze prematurely, affecting the flight and performance.