[Epoch Times, March 24, 2022](The Epoch Times reporter Lin Yan comprehensive report) A Boeing 737-800 of China Eastern Airlines suddenly plunged nose down from cruising altitude on March 21, killing 132 people. At present, a black box of the crashed passenger plane has been recovered, and search and rescue work is still ongoing.
Senior foreign crash investigators said that there have been a small number of crashes in the past in which passenger planes fell from cruising heights, but there have been almost no extreme cases like China Eastern Airlines Flight MU5735 plummeting to the ground.
According to the official press conference of the Chinese Communist Party on Wednesday (March 23), when Flight MU5735 crashed, the air route was “airworthy” and there was no dangerous weather.
Sun Shiying, chairman of China Eastern Airlines Yunnan Company, who attended the press conference, said that the maintenance of the crashed aircraft has been carried out in strict accordance with the maintenance technical plan, and the technical conditions are stable and normal; the three pilots are in good health and complete flight experience. .
Regarding China Eastern’s grounding of all Boeing 737-800 models, Sun Shiying said that this does not mean that the 737-800 will inevitably have potential safety hazards, but an emergency response after a major accident. The conclusion shall prevail.
According to the introduction of the press conference, the China Eastern Airlines flight was from Kunming to Guangzhou at that time. The aircraft entered the Guangzhou control area at a cruising altitude of 8,900 meters (29,000 feet), after which the aircraft “dipped sharply”. The controller called the crew several times but received no reply, and the aircraft’s radar signal disappeared at 14:23.
Crash investigators say MU5735 vertical crash is strange
According to Bloomberg’s report, flight MU5735 was only 160.93 kilometers from its destination Guangzhou before the accident, which was basically when the pilot began to descend in preparation for the landing.
Tracking data recorded by Flightradar24 shows that instead of a gradual descent at the normal speed of a few hundred meters (several thousand feet) per minute, the plane was descending at a rate of 9,450 meters (31,000 feet) per minute, equivalent to a drop of 50 meters per second. Floors.
The plane’s sharp fall appeared to stop for about 10 seconds, and it even briefly climbed. Afterwards, it quickly resumed its rapid fall.
“It’s a weird situation,” John Cox, an aviation safety consultant and former 737 pilot, told Bloomberg. “It’s hard to get the plane to do that.”
Jeff Guzzetti, the former head of the Federal Aviation Administration’s (FAA) accident investigation, also said the crash case was strange.
Guzzet and Kirkus said the Flightradar24 data was preliminary, but the plane’s relatively straight path and the transponder still signaling it didn’t break up in flight, as in some terrorist bombings. as seen in.
A surveillance video of the plane’s last moments circulating on the domestic Internet shows that it fell straight to the ground with its nose down.
The crash of China Eastern Airlines is not the same as the plane crash in the past
Several professionals who have participated in the accident investigation said that the sudden drop of the plane from the cruising altitude is not without precedent, but these precedents are very different from the China Eastern Airlines accident.
For example, Air France Flight 447, which crashed in the Atlantic Ocean on June 1, 2009, had a slower landing. The French Civil Aviation Safety Investigation and Analysis Agency believes that the flight crashed because the speed sensor icy caused confusion among the pilots. All 228 people on board the Airbus A330 were killed.
On February 23, 2019, an Atlas Air cargo plane crashed nose down in a swamp near Houston, but at a lower altitude and much less quickly. The National Transportation Safety Board (NTSB) found that it was the co-pilot who was unaware and turned the nose of the plane toward the ground.
Another similar crash occurred on December 19, 1997, when a SilkAir 737-300 with 104 people on board plunged into a river in Indonesia, killing all on board. According to the Indonesian National Transportation Safety Board, the descent rate exceeded 11,600 meters (38,000 feet) per minute.
The NTSB report concluded that the SilkAir crash may have been deliberately caused by the pilots. Before the crash, the plane’s cockpit and flight data recorder systems were mysteriously shut down, so details about the descent trajectory were not available.
“Something is needed to keep the nose down”
Benjamin Berman, a former NTSB investigator who flew the 737, said it was too early to draw conclusions about the cause of the Eastern Airlines crash.
There are many factors that could have caused the plane to crash, he said, such as some type of failure, or pilot error, or both.
But looking at it now, it seems impossible for each of them. Berman, Guzette and Kirkus all agree that the 737-800, like other planes, doesn’t usually go nose-down at a steep angle.
That means the pilots on the plane at the time may have struggled to do that, or had a very unusual malfunction, Berman said.
There are many situations that can trigger a crash, such as a pilot having a heart attack, accidentally hitting a control stick, or a malfunctioning engine used to raise or lower the nose. But he said such situations tended to result in a briefer response from the plane, as the pilots — at least two pilots on board — could easily correct such mistakes.
“Something (cause) was needed to keep the nose down,” Berman said.
Flight MU5735 had three pilots on board at the time of the accident, one more than the aircraft’s usual pilot configuration.
According to Sun Shiying of China Eastern Airlines, among the three pilots, there is one captain and two co-pilots. The pilot license and health certificate are all within the validity period. Among them, the captain was hired as the captain of the B737 model in January 2018. 6,709 hours, the total flight experience of the first co-pilot is 31,769 hours, and the total flight time of the second co-pilot is 556 hours.
“Before takeoff, the aircraft met the maintenance release standards and airworthiness requirements and was released normally,” he said.
NTSB will participate in the investigation of China Eastern Airlines flight MU5735. A spokesman for the NTSB said on Tuesday that they were in contact with the investigation chief of the Civil Aviation Administration of China and would work with technical advisors from the Federal Aviation Administration (FAA), Boeing and CFM to support the investigation.
Responsible editor: Li Yuan#