Chapter 168 So Boeing is wrong!
At the back of the cabin of flight 9951N, Yang Tian sat quietly in the last row. When he came in just now, everyone in the cabin cast curious eyes at him, which made Yang Tian feel a little uncomfortable.
This time, the Rolls-Royce headquarters specially sent him, a "local", to lobby Xu Cang, which was an important task. Although Xu Cang was an insignificant little person, he was really indispensable at certain special moments.
There are rumors in the aviation circle that Boeing has released a complete set of 737NG drawings to hire Xu Cang to participate in the flight test of the 777. However, rationally speaking, this news is indeed a bit outrageous, but if three people spread it, it will become a tiger, and it seems to be true now.
Of course, even though Rolls-Royce is now extremely anxious to compete with Engine Alliance for the A380 market with its GP2700 aircraft engine, it is still different from the situation with the 777 which is related to Boeing's life and death.
Some time ago, a batch of CFM56 engines on Flight 9451 were exposed to have a problem with short fuel supply pipes, causing CFM's stock price to plummet, and General Motors was also affected.
If Rolls-Royce can deal another heavy blow to GE in the A380 market, that is undoubtedly what it wants to see. However, the development of the GP2700 aircraft engine is unlikely to be slower than that of the Trent900 engine. If it wants to seize the market, it must use extraordinary means.
Generally speaking, a new aircraft engine must first undergo a long period of ground testing before it can be put into actual aircraft testing. Moreover, even if the best simulation is done on the ground, once it is in the air, many unexpected situations may occur. Therefore, actual aircraft testing in the air is a very important part of the development process.
What Xu Cang said before was true. This kind of actual machine test not only requires testing close to or even beyond the limit, but also faces many unexpected failures. The risk factor is too high, especially since Rolls-Royce obviously intends to save some necessary ground testing work in order to gain more time.
This kind of test flight work is simply gambling with your life!
Previously, Yang Tian thought Xu Cang was a complete gambler, and as long as the benefits were sufficient, everything could be negotiated. But the conversation with him just now made Yang Tian feel a little worried, and he was afraid that the lobbying work this time would not be easy.
Perhaps because he was thinking too much, Yang Tian fell into a deep sleep not long after the plane was launched. He didn't know how long it had been, but in a violent shaking for unknown reasons, Yang Tian gradually regained consciousness, and in an instant he felt dry mouth and tongue.
I groped forward and found that the cap of the mineral water bottle in the backpack of the seat in front of me was not closed. Maybe I forgot to drink it when I was on the ground just now.
Yang Tian reached out and grabbed the mineral water bottle with half a bottle of water left. Suddenly, he noticed something strange on the carpet on the ground.
It seemed to be a damp area, probably wet from the water spilled from the mineral water bottle. However, when Yang Tian observed it for a while, he bent down, stretched out his right hand, and put his finger on the damp carpet.
When his fingers touched the wet carpet, Yang Tian frowned immediately, because his skin did not feel the wet wool, but an extremely cold and sharp touch.
"Ice debris?" Yang Tian was stunned: "Ice?"
There was actually a thin layer of ice debris covering the carpet!
Logically speaking, there is an air conditioning system in the cabin of an airplane, so the splashing water should not freeze to the point of freezing.
He spread his five fingers and pressed them against the carpet, and found that there was indeed a continuous and extremely cold air seeping up from under the floor. It was this cold air from bottom to top that condensed the water on the carpet into ice.
This is definitely not caused by the aircraft's air conditioning system, but more like the air rising from the cargo hold below the passenger cabin. However, generally speaking, although there is a gap between the passenger cabin and the cargo hold for air to circulate between them, due to the existence of the pressurization system, in most cases the air in the cabin penetrates from the passenger cabin to the cargo hold, rather than the other way around.
Just when Yang Tian was a little confused about the situation, he also felt that the temperature in the cabin was a little too low, so he pressed the call bell, but the flight attendant sitting in the front did not come over, but shouted at him: "You do it first."
Because Yang Tian was still asleep just now, he didn't know that Mo Shangyun had signaled the cabin, asking everyone in the cabin to stay in their seats and not move.
"It's too cold!" Yang Tian was very easy to talk to. He really didn't press the call bell again. He shouted to the front: "Cold air is seeping up from under the floor. Ask the cockpit if there is any problem with the aircraft pressurization."
During the flight, the noise in the cabin was already quite loud, and what Yang Tian said was a little bit professional, so the flight attendant in front of him couldn't understand it at all.
"Don't move, I'll come find you."
Although the flight attendant didn't quite understand what Yang Tian was saying, he instinctively felt that it was something worthy of attention, so he unbuckled his seat belt and moved to the rear cabin.
Not long after, the flight attendant came to Yang Tian, holding the seat with one hand to stabilize himself, and asked, "What's wrong?"
"Put your palm on the carpet, and you should be able to feel a faint cool air rising up. Based on my knowledge, this doesn't seem normal." Yang Tian explained, "It may be that there is a small problem with the aircraft pressurization. You can report it to the cockpit. Also, it's too cold here. If possible, ask the cockpit to adjust the cabin temperature."
So far, Yang Tian was relatively calm and had the patience to explain the situation to the flight attendant. The main reason was that he did not feel any obvious symptoms of the cabin altitude rising sharply.
If the cabin altitude rises sharply, the human body can sense it in most cases. At least until now, Yang Tian still feels relatively comfortable, except that it is quite cold.
Following Yang Tian's instructions, the flight attendant placed his palm close to the carpet. As expected, he felt a wave of coolness rushing straight to his palm. He immediately exclaimed, "What's the reason?"
Yang Tian didn't know how to explain it to the flight attendant, so he just said, "This... is quite complicated, just tell the cockpit..."
Yang Tian's voice suddenly stopped halfway through his speech, and the expression on his face seemed to be frozen. Such a change made the flight attendant's heart skip a beat, and he immediately asked, "What's wrong?"
"Listen... there's a sound of airflow!"
The flight attendant was startled: "What?"
Yang Tian could clearly hear a continuous hissing sound, like the sound of air leaking from a balloon, which seemed to be the sound of the outflow valve regulating the pressure in the cabin.
However, suddenly, Yang Tian's expression changed suddenly, and he murmured: "Stop?"
As Yang Tian finished speaking, the sound of the airflow suddenly stopped without warning. But the next moment, Yang Tian felt the floor beneath his feet produce a very obvious rise and fall, followed by a deafening explosion.
Then, the pressurized air in the entire cabin seemed to have found an outlet, and it quickly gathered downwards along the gaps in the floor, forming an extremely strong wind in the cabin.
Fortunately, the flight attendant was alert enough in the face of such a sudden change. After a brief shock, he immediately found a seat nearby and sat down.
When the flight attendant sat down, all the oxygen masks in the cabin fell down.
Yang Tian held the back of the seat in front of him tightly with both hands and shouted, "What the hell is going on?"
At this moment in the cockpit, as the explosion sounded, Xu Cang began to grope for the oxygen mask with his left hand. While grabbing the oxygen mask with his left hand, his right hand took off the thrust handle, removed the earphones, and put on the oxygen mask.
As the oxygen mask was put on, oxygen continued to blow in from the mask. Xu Cang took a deep breath, as if he was a drowning person who was saved. When he turned his head again, Tan Heling had also put on the oxygen mask, and Mo Shangyun behind him also put on the oxygen mask safely. Finally, there were no more problems.
Xu Cang turned the switch of the communication panel to the MASK position to transfer the communication to the oxygen mask. Yes, the oxygen mask has a built-in communication device, otherwise after putting on the oxygen mask, the earphones cannot be worn, and communication cannot be established.
However, on the older 737NG aircraft, this communication device switching must be done manually through a certain switch. However, on the slightly newer NG series aircraft, this process can be completed automatically without the crew's operation.
Before this, there were often problems with crew members forgetting to switch the switch, which led to communication failure. In addition, during decompression, people are under great mental pressure, and it is easy for them to forget that the switch was not switched after they found that they could not communicate, which caused more problems.
Of course, the three people in the cockpit were all veterans and would not make such low-level mistakes. Seeing that the other two had safely put on their oxygen masks, Xu Cang used the flight intercom function to call: "Can you hear me?"
Tan Heling next to him quickly responded: "Five at your signal!"
"Okay, that's fine."
This back-and-forth voice test confirmed that the crew communication had been established smoothly. After that, the necessary post-decompression procedures would be carried out.
Tan Heling quickly pressed the altitude alarm cut-off button to eliminate the cockpit altitude alarm. Otherwise, the alarm kept sounding, which was really annoying.
With the cabin altitude alarm cut off, under normal circumstances, it is necessary to adjust the pressurization mode selector to the manual position and then turn the outflow valve to the fully closed position.
However, due to the sudden change in cockpit altitude just now, Tan Heling directly surpassed the checklist and had already turned the pressurization mode selector to the manual position in advance and completely closed the outflow valve. Not long ago, Yang Tian heard the airflow sound suddenly stop because of this action.
Since the corresponding actions have been completed before, there is no need to do it again.
So Xu Cang gave the order directly: "Do the memory project of the emergency descent! Request to return immediately and fly directly to the fifth leg."
Tan Heling's left hand was already on the cover of the passenger oxygen switch. After hearing Xu Cang's words, he hesitated for a moment and looked at the display on the navigation DU: "Flying straight to the fifth approach, isn't it a bit urgent?"
If we fly straight to the final approach from the current position, we will land in five or six minutes. However, there are still a series of checklists to complete, and the approach preparation and briefing have not been completed. Tan Heling is afraid that he will not have enough time to complete them.
"No rush! We can skip some steps if necessary. We need to land as soon as possible. The fuselage of the plane is damaged." Xu Cang made a prompt decision: "Let's do it! "
Tan Heling glanced back at Mo Shangyun. Would Xu Cang's behavior of simply ignoring certain steps be taken into account in the subsequent investigation? This was a huge procedural loophole.
The fact that Tan Heling was so restrained was actually related to Xu Cang. Previously, a certain article in the civil aviation official newspaper criticizing Xu Cang's personal heroism and a group of meritorious pilots jointly demanding the removal of Xu Cang's title disappeared because of Xu Cang's heroic act of turning the tide during the special situation of Flight 9451.
But this does not mean that the impact of all this is really gone like the wind blowing away without a trace. On the contrary, now there has been a very obvious collision of thoughts in the civil aviation industry.
In the past, there was a concept in civil aviation that as long as there were no problems and as long as nothing outrageous was done, both airlines and authorities would often turn a blind eye.
But now the new concept is not only to be correct in the result, but also to pursue correctness in the procedure. In other words, in a special situation, even if the crew lands the plane safely, if the crew's handling procedures are found to be seriously flawed during the subsequent investigation, they may not only not be rewarded, but also be punished.
In the past, Tan Heling would not have hesitated at all. After all, the three people in the cockpit were trustworthy, and omitting some unnecessary steps would not have any impact. But now, influenced by certain concepts in the industry, Tan Heling has become indecisive.
However, as the captain in charge of this flight, Mo Shangyun was still somewhat decisive. After noticing that Tan Heling was looking at him for advice, he shook his head slightly, indicating that Tan Heling should stop worrying and just follow Xu Cang's steps.
After a very brief eye contact, Tan Heling still chose to believe Mo Shangyun. He immediately turned on the passenger oxygen switch, turned on the passenger signal, turned on all external lights, and adjusted the engine start switch to the continuous position. Since the emergency code had been set before, there was no need to touch the transponder.
Xu Cang simply turned the altitude knob a big circle to the left without adjusting the speed window. He pressed the button to change the altitude layer, retracted the thrust handles, and pulled the speed brake to the flight position.
Under normal circumstances, Xu Cang should have pushed the stick forward to achieve a higher descent rate. However, due to the limited pitch control, he could only push the control wheel forward a short distance, which resulted in the aircraft only having a descent rate of 1,500 feet after the speed brake was raised.
If the pitch control is normal, the descent rate can reach nearly 3,000 feet per minute.
However, Xu Cang never worried about the decompression problem. There were enough oxygen masks in the cabin to last for more than ten minutes. According to the plan, they would definitely be able to land within ten minutes. What really worried him was the problem of damage to the aircraft.
There is no doubt that the explosion just now was caused by damage to the aircraft.
“MAYDAY! MAYDAY! MAYDAY! 9951N, cabin depressurization, suspected aircraft structure damage, requesting emergency descent, direct to final approach, land as soon as possible.”
After Tan Heling's report, the tower quickly gave the order: "9951N, corrected sea pressure 2100, heading 010, corrected sea pressure 1011, you can establish No. 05 blind landing."
"Corrected sea pressure 2100, corrected sea pressure 1011, heading 010, blind landing No. 05 can be established."
As Xu Cang expected, the tower gave the approach instructions very quickly. Fortunately, the plane was approaching from south to north, and the area it passed through was all plains, so it could descend to 2,100 meters in one breath. If it was from north to south, it would definitely not be able to descend to such a low altitude.
After Tan Heling finished his reply, Director Liu's voice rang out from the control side: "Xu Cang, a piece of iron plate fell from the sky just now. From my visual observation, it seems to be the elevator component of the aircraft. Is it related to the damage to the aircraft structure?"
When Xu Cang heard this, he cursed inwardly. As expected, the tail of the plane had suffered serious damage when it hit the tail at the beginning of takeoff.
"No, that was a problem caused by takeoff." Xu Cang said, "Director Liu, I will apply to occupy the runway after landing, and I will not leave on my own."
Xu Cang himself had no idea what the condition of the plane was now. To be on the safe side, he decided to let a tow truck tow the plane back.
"Okay, I'll take care of this!" Director Liu said, "You control the altitude yourself and report the blind landing."
This would give Xu Cang a great deal of autonomy, mainly because the airspace in this field has been vacated and is given to Xu Cang to use alone.
"Got it!" Xu Cang said, and then he instructed Tan Heling directly: "Verify the speed. If it's less than 270 knots, lower the wheel!"
According to this descent rate, the aircraft's altitude is too high when it establishes a blind landing and it cannot intercept the glide path. It must first release the wheels in order to obtain a higher descent rate.
Unlike lowering the flaps, which has both height and speed requirements, lowering the landing gear has no height limit, only a speed limit, which is 270 knots.
However, normally in an emergency descent, the speed should be adjusted to Vmo or Mmo, at least to more than 300 knots. But now the speed of the aircraft can't even reach 270 knots, which shows how much the limited pitch control affects Xu Cang.
Of course, this has an invisible benefit. In the case of fuselage damage, Boeing recommends limiting the speed in order to reduce the aircraft load and prevent the fuselage damage from worsening.
This would coincide with Boeing's suggestion.
After doing some mental calculations, Tan Heling realized that the plane was too high and that he would not be able to descend without lowering the landing gear to increase resistance. So he checked the speed and confirmed that he was not speeding, then he lowered the landing gear handle.
He had no objection to lowering the landing gear, but he was quite puzzled by the damage to the fuselage. It was after he closed the outflow valve that the plane exploded. Now that he had experienced the initial panic of decompression, he had the energy to think about a question, that is, whether the damage to the fuselage of the plane was directly related to his manual operation of the outflow valve.
This is not an afterthought, but a very serious issue concerning the division of responsibilities.
However, before Tan Heling could speak, Mo Shangyun at the back spoke first: "The tower saw parts of the elevator falling from the sky. So you mean that the tail of the plane was damaged by the tail scrape just now, and the elevator parts separated because of that? Then the subsequent pitch jam was also an extension of the problem?"
"I think that's it." Even thinking back now, Xu Cang felt that the force of the previous collision with the tail of the plane was really too great. It would be strange if the tail was not damaged. However, even he did not expect that part of the elevator would be directly separated.
Mo Shangyun's face froze. If it couldn't be proved later that the problem was with the plane, then he would be held responsible for a huge loss.
Just like Mo Shangyun, who was worried, Tan Heling also said, "Then was there any connection between me closing the outflow valve and the explosion of the plane?"
When this was mentioned, Xu Cang became angry: "Of course it is related! The derivative problem of tail strike is structural damage. You should actively release the pressure. Even if you do nothing, you can't actively increase the pressure difference!"
"Active decompression?" Tan Heling was stunned. "There is no provision for active decompression in the standard operating procedures for handling tail strikes. I saw a sudden change in the aircraft's pressurization and intervened manually. I followed the SOP."
Xu Cang's face darkened instantly, and he snorted coldly: "So... Boeing is wrong!"
