Mongolian Airlines 1 flight code 7700, which is the highest risk code?

It is reported that Mongolian Airlines flight OM302 from Seoul to Ulaanbaatar was suspected of engine failure, the 7700 code was suspended, and the plane made an emergency landing at Beijing Capital Airport. According to the aerial radar route map, the flight circled over Bazhou for a long time and finally landed at T3, the Capital Airport.

Code 77000 means that if the plane is in flight, it will encounter special emergencies, such as plane failure or sudden illness of people on the plane. The pilot can adjust this code, and the aircraft will be identified separately on the ground air traffic control screen for the convenience of the aircraft.

When the windshield of Sichuan Airlines flight 3U8633 broke, the pilot also hung up the 7700 code, and the ground crew made a forced landing area for the flight in time, so that the plane finally landed safely at Chengdu Shuangliu Airport and all passengers landed safely. It is worth noting that the 7700 code does not necessarily mean that the plane is in danger or hijacked, but there is an emergency. If the plane is hijacked in flight, the pilot will hang up the 7500 code, so that even if the pilot has no time to call the ground command by radio, the ground controller can judge that the plane is hijacked by this signal. The main function of airplane transponder is to assist air traffic control and use air collision avoidance system. As we all know, there are many planes in the world, and they all have fixed orbits when flying.

There are several layers in the sky, namely troposphere, ozone layer and mesosphere. Because of the uneven air density, the troposphere is very bumpy when flying here. Although the middle layer and warm layer are relatively flat, the height here is too high, which requires high aircraft height and consumes a lot of fuel. Therefore, aircraft usually fly in the stratosphere, and only fly in the troposphere during the ascending and descending stages.

In order to save money, airlines will choose to fly in the fixed orbit in the troposphere, which is a golden orbit with great carrying capacity, so ground traffic control is needed to control the flight of these aircraft and avoid the danger of collision.

The code of airplane transponder is a set of 4-digit octal numbers ranging from 0000 to 7777. Most of the codes are in normal use, but under special circumstances, the pilot can manually modify the transponder code on the plane, among which three codes are special, 7500 stands for illegal acts, such as hijacking; 7600 stands for communication failure and 7700 stands for emergency.

The 7700 code hoisted by Mongolian Airlines is an emergency. It can be preliminarily judged that this is not a problem of the plane, but a problem that passengers may suddenly become ill.