Because he knew the cause of the Flight 2610 accident and Yao Yuan was an expert in machinery, he could easily use detailed and credible professional analysis to support his point of view, deduce the cause of the failure, and even analyze the specific process of the accident.
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Coupled with the help of an expert team of more than 30 people from the Chunfeng Academy of Science, the on-site investigation was not only fast, but the cause of the accident was basically revealed.
This made the accident investigation team composed of the Civil Aviation Administration of China and the Safety Supervision Department both surprised and speechless.
After a week of investigation, the accident investigation team produced a preliminary report.
Time goes back to 7:30 in the morning on June 6th.
Flight 2610 from Chang'an to Guangzhou was ready to board passengers, and the airport announcement began to notify passengers of this flight to board the plane.
At 8:00 sharp, the flight crew performed standard procedures such as pre-takeoff inspections.
It should be pointed out that this flight was accompanied by a flight instructor, plus the navigator and flight engineer, making the crew a total of five people.
At 8:12, the crew called the tower to prepare for takeoff, and the tower approved the takeoff.
At 8:13, the aircraft began to taxi and reached the nose-up speed v2. At this time, everything was normal with the aircraft.
At 8:14, that is, 24 seconds after the plane lifted off the ground, an abnormality occurred. The aircraft body swayed greatly. The crew immediately reported that the aircraft was swinging and accompanied by abnormal noises. The cabin sound recorder recorded the "whirring" sound made by the aircraft body.
Aircraft at this altitude and speed are very dangerous.
At 8:15, the captain decided to maintain speed and climb to gain altitude. Afterwards, some people believed that if the captain had aborted the takeoff and made an emergency landing at this time, there might be passengers alive. However, this view was refuted by flight experts, because at this altitude,
In terms of speed, under unpredictable circumstances, continuing to climb and gain altitude is the correct operation.
At 8:15, the captain reported again that the aircraft body was swaying left and right, and the captain and co-pilot were unable to stabilize the flight attitude even if they jointly controlled the control stick.
At 8:16, the captain once again reported that the aircraft was difficult to control, the noise became louder and louder, and the swing amplitude instantly reached 20 degrees, and soon reached 30 degrees.
The tower instructed the aircraft to increase altitude and then return.
At 8:19, the plane reached an altitude of 4,717 meters, but the climb was already very slow.
At 8:21, the flight instructor took over from the co-pilot to work with the captain, but the aircraft sway continued to increase and a warning of excessive tilt angle sounded.
At 8:22, the aircraft automatically raised its head, the elevation angle reached 20 degrees, the air resistance suddenly increased, the speed instantly dropped to 380 kilometers per hour, and the stall warning sounded. Immediately afterwards, the aircraft suddenly rolled to the left, and then entered a large angle.
, high-speed dive, the tilt angle reached 70 degrees, in just 12 seconds, the aircraft dropped from 4717 meters to 2884 meters, an average of 150 meters per second, causing severe overload that far exceeded the rated endurance of Hungry Flight, overspeed warning
resounded through the cockpit.
Also during this minute, the plane disintegrated at an altitude of 2,884 meters...
Yao Yuan looked at these records accurate to the second and remained silent for a long time.
You can imagine how panicked and helpless the more than a hundred passengers in the cabin were when the plane rolled and dived downwards.
The numerous problems exposed by this accident made Yao Yuan, who had just become an air transport practitioner, feel angry, helpless, and heartbroken.
From the analysis of the cabin voice recorder records, the crew was very panicked at the time. After the plane swayed from side to side, no one thought to read the checklist and recovery procedures for dealing with the sway. They were just busy contacting the ground to request help and control the aircraft.
Secondly, when the captain ordered to cut off the automatic controller and switch to manual control, the flight engineer actually refused to execute it!
It can be said that the last glimmer of hope completely disappeared at this time.
This shows how important the captain’s absolute right to speak on the plane is!
The captain and flight instructor were still trying to control the plane until the last moment, but the disaster was unavoidable.
The direct cause of this disaster was that the mechanic plugged the two plugs in wrongly.
The wreckage collected from the accident scene confirmed that the two plugs in the autopilot mounting socket were plugged into each other incorrectly. The green plug that controlled the ailerons was plugged into the yellow plug that controlled the rudder, and the yellow plug that controlled the rudder was plugged into the auxiliary control plug.
On the green socket of the wing.
This is a fatal mistake!
In other words, the problem occurs on the automatic controller!
If the flight engineer carries out the captain's order to cut off the automatic controller, the crew may have a chance to regain control of the aircraft...
After the investigation of the mechanics, electrical engineers, and shift supervisors on duty, the situation became basically clear.
The night before Flight 2610 took off, the supervisor on duty signed the task sheet to agree to release the flight in order to leave his post early, but maintenance had not yet been completed. This was a serious violation of regulations.
If only this were the case, it would not be enough to cause disaster.
When an electronic engineer and two mechanics were performing maintenance operations, they plugged the two plugs into each other incorrectly. Green corresponds to green, and yellow corresponds to yellow. There was a text reminder. As long as you are not color blind, you should not make such a low-level mistake.
At this point, Flight 2610 may even have a chance, as long as the three-person maintenance team of electrical engineers strictly follows the inspection procedures.
However, because the supervisor on duty had signed off, they left without conducting the extremely important third testing procedure!
The maintenance work that night was a simple parts replacement. After the replacement was completed, four inspection procedures were required according to the procedures, namely, self-inspection of on-line damping, internal inspection on on-line damping, and measurement of performance parameters. The measurement of performance parameters is extremely important!
A fatal hidden danger is laid here.
On the morning of June 6, Flight 2610 still had a chance to avoid disaster.
If the crew knows that the aircraft has just undergone a maintenance and pays attention to the reflection of performance parameters while taxiing, they may be able to detect something is wrong.
Unfortunately, there is no such thing, and Northwest Airlines does not have this provision.
After the plane took off, the panicked response measures of the crew and the ground made the accident inevitable. After the flight engineer refused to carry out the captain's instructions, the lives of 160 people were threatened by death, including his own.
No one knows why the flight engineer did this. Maybe it was because he thought the captain was a new captain, or maybe because he didn't agree with the captain's measures. No one will ever know.
This air crash fully exposed the problems of Northwest Airlines' quality assurance system. This air crash was caused by a causal chain composed of multiple factors that was not cut off in time.
In this causal chain, as long as any link strictly implements the procedures, this air crash will not happen. During the maintenance work, the Civil Aviation Administration of China has required airlines across the country to implement strict three inspections, namely self-inspection of maintenance personnel.
Re-inspection involves special inspection by full-time inspectors, and New Beihang has added a third-party inspection on this basis, that is, hiring a professional company to inspect key aspects of aircraft maintenance.
The three-person maintenance team at that time did not perform the third extremely important test, nor did they conduct self-inspections and re-inspections. To say the least, even if they did not perform the third test, if they had performed self-inspections and re-inspections,
Low-level errors such as plugging in too many plugs will definitely be discovered.
Unfortunately none of this happened.
The expert team of the Chunfeng Academy of Science believes that there is also a problem with the design of the Tu-154 and it is a design flaw. This view is more convincing when it comes from experts who have participated in the development of the aircraft.
Such an important plug should have a more sound error-proofing design, such as using a different socket, or changing the appearance and shape. Simply using different colors and labels to remind you is not enough.
In addition, the Tu-154 had more problems exposed in this accident. There is a reason why this aircraft exited the Chinese civil aviation passenger transport market early.
Yao Yuan did not know these specific circumstances before. He requested that all Tu-154s under his banner be converted into cargo aircraft because he knew that the quality of this aircraft was not reliable enough, but he did not expect that it would be so unreliable. Maybe it would not be reliable to convert it into cargo aircraft.
Scored.
He sent a telegram to Lu Sen, asking him to stop acquiring Tu-154.