Weather standard classification of instrument landing system

In the case of bad weather and low visibility, the role of blind descent is particularly prominent. It can provide a reliable approach and landing channel for the aircraft when it is difficult for the pilot to find the runway or sign with the naked eye, so that the pilot can master the position, orientation and descending height and land safely. According to the accuracy of blind descent, blind descent provides different approach and landing standards for aircraft, so blind descent can be divided into I, II and III standards. Class Ⅲ A facility performance: no height limit. When the runway sight distance is not less than 200m, the aircraft is guided to the runway surface by external visual reference in the final stage of landing, so it is also called "ground landing".

Class Ⅲ B facility performance: It is also called "see taxi" when it reaches the runway surface independently of the height limit and external visual reference, and taxies with external visual reference under the condition of runway sight distance of 50m.

Performance of Class Ⅲ C facilities: It can land and slide along the runway surface, with no decision height limit and no external visual reference. If the height from the clouds to the ground is less than 60 meters and the visibility is less than 800 meters, the plane can take off and land, which is a blind descent; When the height of the cloud from the ground is less than 30 meters and the visibility is less than 400 meters, it is a secondary blind descent; Nothing can be seen by the naked eye, and the plane can take off and land completely by automatic navigation of instruments, which is the highest level among the three types of blind descent. The relevant person in charge of the East China Air Traffic Control Bureau told the reporter that the second-class blind landing system of Pudong Airport is the most advanced blind landing system in China. After the second type of blind landing is put into use, if it encounters bad weather such as fog and thunderstorm, as long as the visibility is more than 200 meters, it is possible to complete the normal plane landing.