7500: Aircraft encountered illegal interference (hijacking, etc.)
7600: Aircraft radio communication fails
7700: The aircraft is in an emergency or distress situation
At 11:52 on January 20, 2022, Sichuan Airlines Flight 3U8884 took off from The Capital Airport and, if not unexpectedly, will arrive at Chengdu Shuangliu Airport at 2:30 p.m. The plane was still normal when it took off in Beijing, but during the flight, the flight suddenly hung up the 7700 code temporarily, what emergency was encountered? Are the people on the flight safe?
Lucky! Land safely
It is understood that fortunately, Sichuan Airlines flight 3U8884 landed safely at Chengdu Airport at 2:47 pm on the same day. According to the passengers on this flight: the planes all entered Chengdu Airport, but did not land, but then accelerated to the south and then circled back, when the plane also broadcast that the captain was sure to land safely. But the passengers didn't know exactly what was going on.
What is the 7700 code?
Although the 7700 code is said at the beginning to indicate that the aircraft is in an emergency or distress situation, but to what extent is it urgent, and is there any danger? Generally hung up the code of 7700, often the aircraft has a mechanical failure, may also be the crew or passengers sudden illness and other conditions, this is one of the highest level of code, but the appearance of this code does not necessarily indicate that the aircraft is in a very dangerous situation.
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Add a thrilling case of hanging 7700 code
(1) Mechanical failure class
(1) Morning of May 26, 2019
China Southern Airlines Flight CZ3101, which was flying from Guangzhou to Beijing, was about to land at Beijing Airport, but due to thunderstorms, hail broke the windshield of the A380 aircraft. The plane could only hover over the vicinity of the airport, with bumps and bumps up and down, and even passengers reported the smell of burnt paste, at which point the captain hung up the 7700 code with the answer signal. Fortunately, the plane finally landed safely 22 minutes late, and all the personnel were safe.
(2) Afternoon of October 12, 2017
Flight KC1392 of Kazakhstan's Air Astana, which was originally at a base in Xiamen, was returning after regular inspection and maintenance work. This Boeing 757 aircraft in the takeoff soon after, found the landing gear fault signal, after debugging, the right landing gear can be put down, but not sure whether it can be locked, in an emergency to hang out the 7700 code, the aircraft in Xiamen has been circling over the opportunity, about 3 hours around, and finally landed safely at Xiamen Airport.
(3) Morning of August 9, 2020
Shenzhen Airlines flight ZH9209, which flew from Shenzhen to Xi'an, reached an altitude of more than 9,000 meters less than half an hour after take-off in Shenzhen, but the aircraft had an abnormal signal of the boost instruction, and it needed to descend the altitude according to the disposal procedure, from more than 9,000 meters to more than 3,000 meters. In an emergency, the captain hung up the 7700 code, and then the plane began to return. On the way back, the 7700 code of the transponder was also converted into ordinary code according to the program, which can be described as a false alarm.
(4) February 14, 2016
United Airlines flight UA858 from Shanghai to San Francisco, about half an hour after takeoff, said that the captain smelled something abnormal, so he hung up the 7700 code, emergency return to Shanghai, it is said that the plane did not empty the fuel tank when it returned, but directly landed, fortunately the plane landed safely.
(2) Personnel diseases
December 18, 2017
The international flight IB6888 from Shanghai to Madrid, Europe, Spain, about 2 hours after take-off, was located over Tianjin, and the transponder was hung up with the 7700 code, because a foreign male passenger suddenly had kidney stones and could not insist on long-distance travel, so the plane had to choose to return and take emergency rescue measures.
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What is the use of hanging 7700 code?
Like the above flight encountered in the special situation, some are more urgent, some are not particularly urgent, the flight will be set to the response signal to 7700 this special code, in the flight of the air traffic control radar system, the flight will appear in red logo, easy to distinguish between air traffic control personnel, other crews can also see, so that the aircraft will be on the air traffic control screen alone logo, everyone will assist or avoid to ensure the safety of the flight.
What happened to Sichuan Airlines flight 3U8884?
According to sources uncertain, Sichuan Airlines Flight 3U8884, which flew from Beijing to Chengdu, was originally a twin engine, but as a result, it had a failure and could only use a single-engine flight. This news has not yet been confirmed, if so, it is a heroic captain who is bold and courageous.