Nanfang Daily News (Reporter/Liu Qian) On August 9th, Shenzhen Airlines Airbus 330 aircraft carried out ZH9209 (Shenzhen-Xi'an) flight. Due to a mechanical failure, the crew followed the procedure and dropped to a safe altitude before returning to Shenzhen.
In response, Shenzhen Airlines notified that the aircraft took off from Shenzhen at 7:32 on the 9th. When it ascended to an altitude of 9200 meters in the Guangzhou control zone, an abnormal pressurization instruction occurred. The crew handled the procedure according to procedures, descended to a safe altitude, and returned to Shenzhen on September 9. Landed at Shenzhen Bao'an International Airport at 13 am, safety of man and machine. At 12:00 on the same day, Shenzhen Airlines flight ZH9209 changed its number to B-1036 Airbus 330 to continue its mission and arrived in Xi'an at 14:15.
Question 1 Why should it drop rapidly?
Supercharge failure is not common in actual flight. A senior captain from the three major domestic airlines told reporters that this situation does not happen very often, and there are only a few cases in the country within a year. There are a lot of special handling exercises, and it can be seen from the Shenzhen Airlines report that the crew handling is carried out in full accordance with the process, and the aircraft has been under the control of the crew.”
Why does the airplane descend rapidly when there is a pressurization failure? The captain told reporters that in this case, assuming that the two pressurization systems of the aircraft are both malfunctioning, the aircraft will slowly relieve the pressure. "If the crew does nothing, then the cabin height of the aircraft will eventually rise on this flight. At 30,000 feet (9200 meters), the oxygen mask will fall off, but the general aircraft passenger oxygen can only last for 12 minutes. Therefore, the crew needs to take measures to let the aircraft quickly descend to an altitude of 10,000 feet and 3000 meters to ensure that there will be no shortage of people on board. Oxygen.” So the crew’s approach should be to perform a rapid descent and return or alternate procedures after discovering the fault. The Shenzhen Airlines crew’s handling this time is in compliance with the process.
A member of the Science Squirrel Society and aviation blogger Shou Tuo also said: “After the cabin pressurization system fails, the crew will lower the altitude according to the disposal procedures to prevent the cabin from being hypoxic. The descent rate of about 1,000 meters per minute is based on the process and is not out of control. Crashed."
Doubt 2 a sudden drop of 6000 meters in 2 minutes?
Regarding the speed of descent, some media reported that it "suddenly dropped 6000 meters in 2 minutes", but Shenzhen Airlines made it clear that the actual speed was not so fast. According to the flight software, the flight data of the flight can also be queried. The aircraft began to descend urgently at 7:52 and leveled at about 7:57. It dropped 18,000 feet in about 5 minutes, with an average of 3,600 feet per minute.
According to the conversion of feet and meters, 3,600 feet/minute = 1097.28 meters/minute, the speed is not so fast that the speed drops to 6000 meters in 2 minutes.
Question 3 How do the passengers on board feel?
Will such rapid descent passengers have a strong sense of weightlessness? The thin camel described it like this: "It's like riding a roller coaster at most, or a child's kind." The captain thought that the speed can be said to be a rapid decline, "but it is a little faster than normal, and sometimes it can fly normally. At this rate of decline, passengers won’t feel much, and it’s not much different from the normal decline."
In addition, this flight did not release the oxygen mask, which means that the cabin did not undergo emergency relief under the "sudden drop". It can also be seen from the Shenzhen Airlines report that after the plane landed, the man and the plane were safe, and the passengers changed the plane to continue the journey, and no one was injured.