Fly-by-wire, or fly-by-wire control, is the most solid foundation for Airbus to overtake Boeing and the original driving force that enables Airbus to stand at the top of the world's large passenger aircraft market.
Compared to the early days of the A300, when Airbus had to beg airlines to buy a few aircraft, after launching the fly-by-wire A320, Airbus turned around and, after lagging behind the Boeing 737 series, continued to advance towards the position of the best-selling mainline passenger aircraft in history.
The so-called control system is nothing more than allowing the aircraft's control surfaces to change their state according to the pilot's will, thereby changing the aircraft's attitude.
Once upon a time, Boeing designed a set of exquisite cable transmission for this purpose, and it has been tested for decades. It is so perfect that Airbus never thought of surpassing Boeing in cable transmission from the beginning of designing A320.
At that time, the A300 was not considered indispensable to the world's major airlines, but was better than nothing. It was only because Airbus sold the A300 that its sales were not too bad.
Therefore, when Airbus sensed the huge demand for narrow-body aircraft other than 737 and DC-9 passenger aircraft in the world civil aviation market, it decided to open up a new track for itself.
One of the major changes of the Airbus 320 compared to the 737 is that it uses a lot of composite materials, which of course makes the Airbus 320 very vulnerable to lightning strikes, and another is the use of fly-by-wire control.
Although the Concorde has come to the end of its life due to the Paris air crash, as the "spiritual successor" of the Concorde, the Airbus 320 has perfectly inherited the Concorde's fly-by-wire control, with assistance from the French Mirage 2000 team. It has finally pioneered a new track of fly-by-wire control in the field of civil airliners in addition to cable transmission.
Of course, the Concorde itself is a special case and should not be included in the scope of generalization. Of course, even if you look into it in depth, the Concorde itself has a close relationship with Airbus.
Therefore, the groundbreaking technology of fly-by-wire control became an extremely critical turning point for Airbus to reverse its decline.
In this control method, the pilot's control is no longer directly connected to the aircraft's control surfaces. Instead, the pilot's control instructions are converted into electrical signals, handed over to the flight control computer, and then transmitted by cables to drive the corresponding hydraulic devices to control the aircraft's control surfaces.
At the beginning, the flight control computer of Airbus 320 used Intel's 80286 CPU, with a frequency of only 10mHZ and a running memory of only 2.5mb. It was this "core" that now looks crude that overturned the entire aviation industry and created a giant aircraft manufacturer that stands on par with Boeing.
Airlines are very fond of Airbus, and even if some "small" accidents occurred during the test flight, this did not make them lose patience with the Airbus 320. Not to mention that British Airways and Air France treat the A320 like their own sons and naturally support it, even Boeing's own son United Airlines couldn't help but order a few, which is a poaching of Boeing's customers.
Moreover, because the cable transmission is removed, the A320 has greatly reduced the weight of the aircraft, and the use of composite materials makes this feature more obvious. In addition to adding more brushes to prevent lightning strikes, the extra redundant space can also allow the aircraft to be modified in a variety of ways according to the needs of airlines.
From small to large, there are 318, 319, 320 and 321, with various gears for you to choose from. The airlines are crazy about it, and they love it so much.
But Xu Cang doesn't like it!
Airbus has reduced a significant portion of the workload of flying, but its fly-by-wire system has made flying something like a video game.
That’s right, in Xu Cang’s opinion, Airbus has gamified flying work .
Most of the time, Airbus can make pilots feel at ease because of its convenient control method and powerful computer functions. However, in some special cases, Boeing's traditional transmission can save lives, while Airbus's fly-by-wire control can become a fatal knife.
In the first class cabin, Xia Shuyue saw that Xu Cang seemed to be asleep, so she gently fastened his seat belt.
Although extremely faint, the even breathing sound continued to reach Xia Shuyue's ears, which made her feel more at ease than thousands of words.
Perhaps, as Xu Cang said, he was lucky in misfortune.
The pistol bullet went straight through the shoulder and did not roll around in the body. Apart from the blood loss and pain, the impact was much smaller than other situations.
Xia Shuyue sat quietly beside Xu Cang. After fastening Xu Cang's seat belt, she hesitated whether to give Xu Cang some water. Even with the not-so-obvious starlight and moonlight, Xia Shuyue could still see Xu Cang's chapped lips.
Seeing Xu Cang's pale face, Xia Shuyue felt a pain in her heart. In ten minutes at most, Xu Cang would have to be woken up again, because everyone in the cockpit, or to be more precise, on the entire plane, was counting on him.
The final approach and landing will still be the responsibility of Xu Cang.
The greater the ability, the greater the responsibility, but Xia Shuyue does not want Xu Cang to accept this responsibility because he is working too hard.
"Wait a little longer." Xia Shuyue gave up the idea of ​​giving Xu Cang water.
Just when Xia Shuyue was thinking about something, the plane suddenly rolled sideways with an extremely obvious slope. Now, Xia Shuyue also had some flying experience, and this time the slope was probably more than 40 degrees.
Xia Shuyue couldn't help but complain in her heart: "What are you doing!?"
There is no need for the people in the cockpit to do anything, just fly the plane steadily to the designated area and then let Xu Cang take over. Can't it be done?
What Xu Cang needs most now is rest. What if his condition changes so drastically and he wakes Xu Cang up?
Although it seemed that Richard Bayer and Xu Cang had a good relationship in private, Xia Shuyue still criticized him a few times in her heart.
However, Xia Shuyue did not wear a seat belt when she sat down, and the sudden change in the plane's state made Xia Shuyue feel weightless for a moment. However, Xia Shuyue reacted quickly and grabbed the armrest immediately, so no serious consequences occurred.
After thinking for a while, Xia Shuyue started to fasten her seat belt after the plane stabilized a little. At the same time, she glanced at Xu Cang's seat belt and was glad that she fastened Xu Cang's seat belt first. If she didn't fasten Xu Cang's seat belt, the consequences would be...
However, there was one thing that puzzled Xia Shuyue. That was that after the plane suddenly experienced a drastic change in slope, it did not level out, but almost maintained a rolling state.
"Is it turning?" Xia Shuyue thought to himself, maybe it encountered some air currents?
However, thinking back, things didn't seem that simple. In the information she had just received, the plane should have been flying normally straight to the west. At this time, the plane was already in an emergency state. Even if the subsequent communication was re-established, it should not be directed to make a large maneuver.
"Or was it the weather?"
Click!
Xia Shuyue had just fastened her seat belt and was thinking about whether she should ask the cockpit in front if there was any problem.
She was not completely ignorant of Airbus, although for a short time. But when she was studying at Yanshan Aviation School, Xu Cang assigned her a one-on-one theoretical instructor. Xia Shuyue put in a lot of effort and she had mastered many theories very well, except for the lack of practical training.
Judging from the current situation, the problem with the plane is very complicated. What she is worried about is the escalation of the fault. Given Xu Cang's current condition, he is not able to accept more complicated problems.
No energy left!
However, at the moment when Xia Shuyue had this thought, the plane, which was originally maintaining a slope, suddenly increased its slope and rolled sideways at an angle of nearly ninety degrees. For a moment, Xia Shuyue even felt that the plane was going to turn upside down. The obvious and continuous feeling of weightlessness invaded Xia Shuyue.
However, Xia Shuyue did not react overly violently. She forced herself to calm down. Although she was wearing a seat belt, her right hand still held the handrail and her left hand was holding Xu Cang's belt.
Although Xu Cang was also wearing a seat belt, with such an exaggerated change in condition, no one could guarantee whether the seat belt used by the passenger was useful.
However, Xia Shuyue was relatively calm. There were screams coming from the front and rear cabins, which came from the flight attendants. Even for the flight attendants with flying experience, the situation just now was extremely terrifying for them.
Perhaps we should be thankful that there were few people on the plane. If there were many people in the economy class, there might be passengers who did not fasten their seat belts properly. The impact just now was enough to throw an adult out.
At this time, Xia Shuyue was really glad that she had fastened the seat belt for Xu Cang.
If I had been slower, the consequences would have been disastrous.
With Xu Cang's current physical condition, if he was thrown out, he would probably be crippled.
Fortunately, after the plane formed an extremely exaggerated slope, there was no further unpredictable changes. The plane just maintained a huge slope, which made the cabin always tilted.
Although Xu Cang was fastened with a seat belt and did not encounter any serious problems, his head was violently shaken by inertia, waking him up from his rest.
Many people should know that this kind of direct awakening is very stimulating to people.
As soon as Xu Cangfu woke up, he felt his heart pounding as if it was about to jump out of his throat at any moment.
"What's wrong?" Xu Cang covered his chest, trying to calm his heartbeat, but in comparison, he was more concerned about why the plane was in its current state.
Such a terrifying slope is obviously abnormal.
At this time, Xu Cang noticed that Xia Shuyue was beside him, and even had one hand on his belt, so he grabbed Xia Shuyue's wrist with his right hand: "Help me."
"You want to go to the front?"
Xu Cang only felt dry mouth and tongue at the moment. He had just rested without drinking water. Now his throat felt like it was on fire and it was unbearable.
However, solving the current situation is the most important thing.
"Yeah." Xu Cang took a deep breath. He felt his heart beating too fast and his breathing was unstable. "Anyway, it's impossible for a plane to maintain such a slope for a long time. They haven't corrected it yet. There must be a problem, and it's an unsolvable problem."
At this time, the airport was tilted greatly, and Xu Cang couldn't walk even with the help of Xia Shuyue.
Xia Shuyue looked at Xu Cang deeply and paused for a moment: "Then hold on to me tightly."
As she spoke, she unbuckled her seat belt first, then stood up and helped Xu Cang up.
Originally, Xia Shuyue wanted Xu Cang to carry her on her shoulders, but at this time, the short distance to the cockpit was too difficult to walk. If something happened again, it might be difficult to use her on her shoulders, so Xia Shuyue directly put Xu Cang's right arm around her waist, and at the same time, she also put her left hand around Xu Cang's waist to stabilize him.
Fortunately, they were sitting in the front row, not far from the cockpit, just a few steps away, and the cockpit door was not closed.
Except for the crazy white man, everyone on the plane was looking forward to the plane landing safely. Whether the cockpit door was closed or not had no effect. On the contrary, it was convenient for Xu Cang to enter and exit.
Given the current state of the aircraft, if any problem occurs, it would be too troublesome to free up hands to open and close the door.
Xia Shuyue supported herself on the wall of the front cabin workroom with her right hand and helped Xu Cang walk forward. At this moment, the chief flight attendant in the flight attendant's seat noticed Xu Cang who was about to enter the cockpit for the second time.
At this time, the chief flight attendant realized that the problem might be more serious than expected, and his expression became sad.
Like the captain, she wants money, but she doesn't want to die.
"Mr. Xu Cang, can we survive?" the flight attendant asked tremblingly.
Xu Cang glanced at her and didn't want to answer, but suddenly, he opened his mouth and whispered: "If you can survive, it's not because I want to save you."
Under the astonished gaze of the chief flight attendant, Xu Cang slowly entered the cockpit.
As soon as he entered, Xu Cang discovered that the two people inside were so focused on dealing with the problem that they didn't even notice him coming in.
He patted Xia Shuyue's left arm, motioning her to go back to the first class cabin and sit down.
At this time, Xia Shuyue was very well behaved and walked out.
After Xia Shuyue left, Xu Cang did not speak immediately. Instead, he glanced at most of the panels that were out of service and suddenly asked, "Is there a problem with the control signal transmission?"
Richard Baier and the captain were focused on how to deal with the problem.
Under the captain's control, the aircraft formed an extremely exaggerated slope, which made the two of them dare not continue to input control signals. They could only let the aircraft maintain such an exaggerated slope.
Xu Cang suddenly spoke like this, and the two people in front were startled. After noticing that it was Xu Cang who came in, the captain was obviously relieved: "Mr. Xu Cang, I'm sorry to disturb your rest. There was a small problem."
"Small problem?" Xu Cang sneered, "If my friend hadn't fastened my seat belt just now, I would have been thrown out with your moves. Do you think it's a small problem? Also, you noticed that the plane had a slope, but didn't you notice that the plane was descending?"
The captain looked a little embarrassed. The passenger's seat belt was not as secure as the pilot's. Although the aircraft's state changed greatly, there was no risk of the two people in the cockpit being out of their seats.
However, the situation in the cabin was not so good, especially since Xu Cang mentioned that he almost didn't wear a seat belt, which was indeed quite dangerous, and it was no wonder that Xu Cang was angry.
As for the descent problem, it was indeed because Richard Baier and the captain paid too much attention to the side stick problem. In fact, the throttle of the aircraft was not small, but at a large slope, the lift was greatly decomposed, and the throttle was naturally insufficient.
The plane's descent rate was not very fast, so it did not cause much stimulation to the two people in the cockpit, so they did not notice it.
The captain increased the throttle with some difficulty and finally stabilized the aircraft's altitude.
However, now that the electrical system failure has affected the display system, they cannot see the specific data of the engine and can only rely on the aircraft data to try to figure out a suitable thrust value.
Of course, this is not difficult for a pilot.
Richard Bayer had a better relationship with Xu Cang, so he did not dwell on the previous problem. Instead, he immediately explained the fault: "The current situation should be what you said. The control surfaces of the aircraft cannot respond to the crew's control at all. There is indeed a possibility that there is a problem in the transmission of the control electrical signal, but this situation should be rare."
"It's rare." Xu Cang didn't stand there all the time, but patted the captain's shoulder: "Come out."
The captain was stunned for a moment: "You want to take your seat?"
"Yes, I will take control next." Xu Cang said calmly.
The situation of the plane was far more complicated than he had imagined. If he handed the plane over to them again, who knew what problems would arise?
Even though I'm very tired and don't know if I can hold on any longer, it's time for me to handle it myself.
"Are you okay?" Richard Bayer looked at Xu Cang's pale face and felt nervous: "Or, you should continue the approach according to the plan..."
"No need!" Xu Cang glanced at the captain indifferently: "Get up."
The captain also noticed Xu Cang's weak nature. Although he wanted to hand this hot potato to Xu Cang, reason told him that Xu Cang could not hold on for too long. The best way was to let Xu Cang rest until the approach, rather than let Xu Cang start worrying at such an early time.
So, he did not stand up immediately, but first looked at Richard Bayer.
Richard Bayer sighed: "Forget it, get up."
The captain had the least say in the cockpit, so since Richard Baier had said so, he had no choice but to obey and quickly unbuckled his seat belt.
Soon, the right seat where the captain was sitting was vacated. Due to the gunshot wound on his left shoulder, Xu Cang had a hard time getting seated. In addition, the was tilted, so he took a lot of effort to get on the plane.
Xu Cang could only move one hand and was unable to fasten his seat belt.
After seeing this, Richard Bayer unbuckled his seat belt first, then turned sideways to help Xu Cang, and apologized: "Xu Cang, I'm sorry, I still have to hand it over to you in the end."
Soon, the seat belt was fastened, and Xu Cang held the side bar with his right hand, apparently trying to move it.
But just this small movement scared the captain who had just sat in the observer's seat and screamed: "Don't move!"
The captain may have realized that his voice was too high, so he lowered the volume of the next sentence: "I mean... I just moved the side stick slightly just now. I can be sure that under normal circumstances, the aircraft will never form a bank angle of more than ten degrees, but..."
"How did it end up like this?" Xu Cang frowned.
"My side stick had problems first." Richard Baier added: "Airbus's fly-by-wire control has been tested on Concorde and can operate stably in complex supersonic environments. It should be said that it is trustworthy in terms of stability. Moreover, Airbus's fly-by-wire control version has been optimized and should have stronger anti-electromagnetic interference characteristics!"
"If it's not a problem with the transmission cable, perhaps the flight control computer is malfunctioning." Xu Cang gently fiddled with the speaking button on it with his right hand.
The side stick's control electrical signal does not directly act on the rudder hydraulic adjustment system, but will only take effect after being processed by the flight control computer.
If the flight control computer itself has problems processing the control signals, it is equivalent to a problem with a person's brain, which will naturally be reflected in the movements of the hands and feet in various unintended situations.
"If it's the flight control computer..." Richard Bayer's eyes lit up: "If there's something wrong with the flight control computer, should we reset it?"
The captain asked incredulously: "Pull out the circuit breaker? This won't have any effect?"
Neither Airbus nor Boeing recommends pulling out the circuit breaker during flight. Pulling out the circuit breaker is only used to reset the aircraft in certain special circumstances.
The operation of the circuit breaker can usually only be performed when the maintenance personnel are present and performing ground maintenance.
There are too many things that are affected by the jump switch. Once it is operated in the air, it is very likely that solving one fault will cause two or more other faults.
Richard Bayer also thought of this problem. At least now the plane could not withstand any more problems, so he habitually handed the decision to Xu Cang: "Xu Cang, what do you think?"
Xu Cang licked his dry lips and said, "It's too early. It's too early to pull the switch now. It's not time yet."
"What's the current situation of the plane?" Richard Baier asked worriedly.
Now the side stick of the plane is like a time bomb, no one dares to touch it. Although this bomb should not explode if it is not touched, but we can't just ignore it, isn't it a sword of Damocles?
Moreover, the slope of the aircraft was too large. If there was a severe air flow impact, and if the direction was consistent with the slope of the aircraft, the two factors combined, the aircraft might not be able to maintain its position, and it would really be close to turning over.
Xu Cang has done the inverted flight operation before, but this does not mean that inverted flight is not a routine operation for large passenger aircraft. There are still huge risks.
But if he didn't reset the flight control computer, Richard Baier didn't know what else to do.
In the event of an electrical system failure, the ECAM system becomes unavailable, making it impossible to obtain fault handling guidance.
"Shall I move the side stick?" Xu Cang thought it would be better to experience it himself: "You are right. Compared with the problem with the transmission cable, the probability of the flight control computer having a problem may be greater. However, I am more inclined to believe that this kind of fault is intermittent rather than continuous. Shall I try it?"
Not to mention the captain, Richard Baier's reaction was also obviously very stressful and nervous: "Xu Cang, why don't we just forget it? If there is an unexpectedly fast change in status, we won't be able to control the plane."
"Aren't there still throttle and rudder? Can't we correct the plane using the differential throttle and rudder?" Xu Cang asked back.
Now Xu Cang has no strength left and can hardly move the rudder, but the throttle is on his left, and he can't even move his left hand, so he can only let Richard Bayer do it.
For Xu Cang, he can fully control an airplane just by relying on the throttle, not to mention the assistance of the rudder, which reduces the difficulty a lot.
However, this kind of thing that comes naturally to Xu Cang is already a very challenging operation for a pilot of Richard Bair's level.
The muscles on Richard Baier's face stiffened. In the end, he did not answer the question directly, but sighed softly: "If possible, please don't move the side stick, okay?"
Xu Cang was stunned for a moment, didn't say much, just nodded, and gave up the idea of ​​moving the lever.
However, the problem always exists, and he can't really ignore it all the time, otherwise the plane will keep circling in the sky.
"The last control action was completed by the right side stick?" Xu Cang suddenly asked.
Richard Baier nodded: "Yes."
"Then you suppress the sidestick signal on my side."
Unlike Boeing's controls, the Airbus side sticks are not rigidly connected, and the controls on both sides can be superimposed, but the superposition of the two cannot exceed the control limit.
However, if both side sticks input control signals at the same time, then there will be a "double control" alarm. However, now the electrical system failure has spread, the warning system is also affected and no warning sound will be generated.
It is extremely taboo to operate both sides at the same time in Airbus flying. In order to prevent accidental dual control problems, there will be a red button on one side of the side stick on both sides. No matter whether it is the left or the right side, as long as you hold the side stick, the red button is on the thumb side.
This red button has two functions: one is to provide the function of manually disconnecting automatic driving, and the other is to obtain priority in operation.
The side stick on which the red button is pressed continuously for a short period of time gains control priority. Under normal circumstances, there will be an electronic alarm to prompt the crew on whether the left or right side has priority. At the same time, a red warning sign appears in front of the crew on the other side, which means that the control right on your side is temporarily suppressed.
If you keep pressing the red button on the side stick for more than forty seconds, the side stick signal on the other side will be completely suppressed. If you want to restore it, you need to perform some additional operations.
Suppressing one party's side stick for a long time is not a common operation, nor is it a solution to control signal failure. It is just Xu Cang's experience.
Richard Bayer naturally knew that this was not a standard or recommended procedure, but since Xu Cang said so, he listened. After all, this did not seem to be a dangerous action, and even after suppression, there was still a way to recover.
"OK!"
Following Xu Cang's request, Richard Baier began to press the red button on his sidestick. As time went on, after counting for more than 40 seconds, there was no indication in the cockpit. Of course, this was a malfunction, but as long as the sidestick worked properly, Xu Cang's sidestick should be suppressed.
Xu Cang waited for a moment and said, "Richard, move the side stick slightly."
Richard Baier's mouth twitched: "Do we have to move the lever in the end?"
"If the aircraft has an unexpected state change and the throttle is at two-thirds of the position, do not continue to input control inputs. In this way, the aircraft will not have major problems."
"Really?" Richard Bayer was very skeptical.
Xu Cang forced a smile: "You should believe in the stability of the 320. When the altitude is high enough and the throttle is appropriate, it will correct the excessive state deviation by itself. Even if you want to reset the jump switch, you still have to try to move the stick in the end. This is a necessary step for verification."
Richard Bayer was speechless. That’s right, no matter what you do, you have to verify it in the end. This step is inevitable.
"Then I'll move, just tilt it a little." Richard Bayer raised his hand to demonstrate to Xu Cang the extent to which he was going to move to the left. He took a deep breath, hesitated for a moment, and gently moved the side stick to the left a very small amount.
To be honest, not only Richard Bair, but also the captain sitting behind him was nervous. However, to their surprise, the plane did not show any strange changes in state, but seemed to reduce the slope slightly according to Richard Bair's control.
Richard Bayer was stunned for a moment, then he was overjoyed: "It works, it seems to be working!"
"Wait a moment, and then correct the aircraft status according to the amplitude just now." Xu Cang also breathed a sigh of relief. Completely suppressing the sidestick signal on one side was an attempt made in his haste. In fact, it had no basis in reality and was a completely helpless act.
Fortunately, it actually worked.
If this is not possible, then Xu Cang will have to use the accelerator to land.
It’s not that Xu Cang can’t do it, but Xu Cang’s condition is very bad now. What hinders him is not the technology, but his body.
Xu Cang guessed that the solar storm might have suppressed some of the flight control computer's computing performance, just like the brain had crashed. Signals could not be fed to it too quickly or too frequently, and control signals could only be fed in at intervals and in small amplitudes.
However, Richard Baier and the captain did not actually perform excessive manipulation just now, but problems still occurred, so the reason is not very clear.
Of course, no matter what the reason is, the crew does not need to understand it at all times. It is enough to know that the deviation is being corrected.
Although the correction is slow, everything is moving in the right direction, isn't it?
Richard Bayer adjusted his mood a little. Now Xu Cang had taken the most important first step for him. He could leave the rest to him. At least he was confident in such an operation.
"I'll level the plane first," said Richard Baier.
Although the plane still had a large slope at this time, Richard Baier was full of confidence.
However, before that, he needed to adjust the throttle of the plane.
Due to the decrease in the bank angle, the lift decomposition is less, so such a large throttle is not needed at this time. In order to maintain the aircraft's altitude, Richard Baier needs to adjust the throttle, or to be more precise, reduce it a little.
Without engine data, Richard Baier could only move the throttle back slightly by feel.
This was a fairly routine operation, however, what no one expected was that although it was an operation to reduce the throttle, suddenly, Engine No. 1 roared to life, and the thrust increased rapidly without warning.
The problem is that only the No. 1 engine on the left increased its thrust, creating a thrust difference in an instant.
If it happens at a normal moment, this sudden thrust difference will at most form a huge drift in an instant, which is still controllable, just like when a single engine occurs.
But now is not a normal moment. The plane itself has a huge right bank, and the thrust of the left engine is much greater than that of the right engine, which causes the plane to increase the bank rapidly.
Moreover, due to excessive increase in the throttle of the No. 1 engine, the nose of the aircraft rose up when the total throttle was excessively increased. In this case, the aircraft tilted directly to the right and fell backwards.
spiral!
Due to various unpredictable operations, WN3102 accidentally went into a spiral.
Richard Bayer may not have anticipated this situation at all, and did not react immediately. In comparison, Xu Cang reacted quickly, even though his physical condition was very poor.
He lifted his left foot, trying to stop the plane's spin before the second turn.
At the beginning of a spin, the aircraft has not yet converted much potential energy and has not accumulated much speed, so it is relatively easy to recover.
If Xu Cang was in normal physical condition, he would be confident that he could correct it in the first lap. However, due to objective physical limitations, his movements were still a beat slow, but he still made it in time.
However, the accidents did not stop. After turning a circle, the plane began to dive rapidly. Such a horrible fall caused the blood in Xu Cang's body to rush to his upper limbs under the action of inertia. He felt that his already abnormally fast heartbeat seemed to be about to explode. Then, the left shoulder bandage that had been used to stop the bleeding suddenly burst into thick blood.
Blood accumulated in the upper limbs, which caused Xu Cang's upper limb blood pressure to increase sharply. The shoulder wound was like a floodgate for venting. Even though it was bandaged, a large amount of blood was still squeezed out.
Xu Cang had already lost a lot of blood, and now he felt dizzy, his head was heavy, and he almost lost the ability to think.
Unconsciously, Xu Cang lowered his head, and when he looked around, he found that the nails on his right hand were gradually turning blue-purple.
At this moment, Xu Cang's heart sank to the bottom.
Cyanosis!
He couldn't see the color of his lips, but since there was already cyanosis on his nails, his lips should be purple by now.
An indescribable feeling of restlessness came over him. This was not Xu Cang's real emotion, but was affected by physiological factors.
This is a very dangerous signal because it is a sign of... shock!