Legendary Captain

Chapter 372 The God of Mental Calculation!

In today's society, what is the most important thing?

data!

Especially for certain sensitive individuals, their data is of paramount importance.

Why did Xu Xian react so strongly to the terrain data near Longjiang Airport? Because if this terrain data were leaked, Longjiang Airport would be at risk of being precisely targeted at any time.

Longjiang Airport is the headquarters of the South China Sea Fleet, a fact that Xu Xian simply cannot accept.

Missile guidance systems have diversified, but one key method remains terrain-matching guidance. In this extremely urgent situation, the military simply doesn't have time to process terrain data, meaning the uploaded information must be of military-grade precision. However, this highly precise terrain data is precisely what makes terrain-matching guidance so effective. Imagine being able to fire however the enemy wants, without the slightest deviation, during times of chaos?

Xu Xian hadn't noticed before that Zhangzhou Airport and Longjiang Airport were quite close, but luckily he casually asked air traffic control. Air traffic control mentioned that the South China Sea Fleet had called to confirm the situation, indicating that the military also realized the risks of uploading terrain data. As the South China Sea Fleet Command could potentially be severely attacked, they had to personally verify the situation; otherwise, given the command's safety, they would absolutely not hand it over to others for judgment.

Critical and sensitive information, such as topographical data concerning the fleet headquarters, is generally not allowed to be transmitted through civilian equipment. Moreover, the aircraft is not manufactured domestically, which undoubtedly increases the risk of leakage.

However, the military ultimately agreed. This wasn't to say there was no risk of data breaches or a potential attack on the command headquarters, but rather that the South China Sea Fleet, as the people's own army, couldn't stand idly by, even if it meant incurring significant losses.

Once the data is uploaded, the South China Sea Fleet Command will be essentially rendered useless and will have to change its address. Otherwise, it is unacceptable to remain under the constant shadow of precision strikes.

Some might think that we are currently in a time of peace and national strength, so what villain would dare to challenge the might of Heaven? But as the ancients said: "War is a matter of vital importance to the State; it is a matter of life and death, a road to survival or ruin. Hence it is a subject of inquiry which can on no account be neglected."

The South China Sea Fleet is crucial to the defense of the entire vast southern sea area, and any degree of caution is warranted.

However, along the entire southern coast, there are very few areas with rolling hills suitable for building an airport and with a good natural deep-water port nearby.

The South China Sea Fleet Command doesn't even know if they can find a better location than Longjiang Airport. Even if they do, the financial and human resources required to change the address are unimaginable.

Even knowing all this, the South China Sea Fleet still agreed to upload the terrain data. This demonstrates the spirit and awareness of the People's Liberation Army.

However, Xu Xian couldn't accept this!

"Blind flight? How are you going to fly?" The captain frowned, looking at Xu Xian's resolute gaze. "Xu Xian, sometimes you shouldn't be reckless. I can tell you're worried that uploading data might cause some losses for the military. But nothing is more important than human life; you can't joke around with human lives."

Xu Xian's gaze darted back and forth between the wind direction and speed, the airspeed indicator, the heading, and the clock. He closed his eyes slightly, and a scene involuntarily flashed through his mind. It was a brief terrain display image obtained after restarting the FMC.

The navigation page displays distance circles, allowing Xu Xian to calculate the relative distance to the aircraft based on the terrain image he has memorized.

"We just checked the terrain display," Xu Xian's pupils began to contract slightly, and his breathing gradually became rapid.

"You saw the terrain display?" The captain paused for a moment, but quickly realized that Xu Xian was referring to the brief terrain display image obtained after restarting the FMC. He widened his eyes and muttered, "That was then, but is it still there now? What's the point?"

The captain didn't understand the point of mentioning the terrain display function that had just been briefly restored.

"Yes!" Xu Xian said firmly, "I've memorized it all!"

"What did you say?" The captain gasped, finally understanding what Xu Xian was trying to do: "You want to navigate obstacle courses from memory? Do you know what you're saying?"

The captain could hardly believe what Xu Xian was saying. The terrain image that had just been displayed only lasted for a few seconds, which was too short. He hadn't even had a chance to look at it closely before the image disappeared.

And there's another crucial point: the area ahead of them is riddled with mountainous obstacles. In a plain, there might only be one or two towering peaks, making the terrain image relatively simple. If that were the case, Xu Xian could say he remembered it, and the captain could probably manage to recognize it even if he held his nose. However, the terrain in front of them is extremely complex; even if he had ten minutes, let alone a few seconds, he might not be able to fully memorize it.

This kind of thing isn't something you can just do halfway through; even a slight mistake could lead to a crash and loss of life.

Xu Xian's eyes began to bloodshot noticeably as he slowly turned to the captain: "I know what I'm talking about."

At this moment, Xu Xian's brain was working at breakneck speed, operating beyond its limits, with his heart acting as a powerful power source, supplying fresh blood to his brain.

"But even if we remember it, how do we determine the relative position of the aircraft?" the captain asked anxiously.

"I know the speed, heading, wind direction and speed, and time, so why can't I determine the aircraft's position?" Xu Xian asked rhetorically.

"What about velocities? Wind direction and speed are not fixed, the heading is not fixed, the speed is not fixed, and the aircraft's position needs to be constantly updated and calculated. How are you going to do that? Do you have a flight ruler? Even if you do, you won't have enough time to calculate it!"

In theory, with airspeed, heading, wind direction and speed, and time, it is possible to determine the aircraft's position, but the amount of calculation involved is extremely enormous.

In a stable environment with consistent wind, airspeed, and heading, many pilots might be able to determine the direction. However, the external turbulence is now extremely strong, airspeed, wind direction and speed are unstable, and heading is also unstable, making it virtually impossible to calculate the aircraft's yaw angle.

Except when there is a direct headwind or tailwind, as long as there is a crosswind, the aircraft will generate a yaw angle, that is, there is an angle between the heading and the track.

It is clear that the aircraft is currently in an environment with crosswinds, and the heading displayed on the aircraft is not the direction of the aircraft's actual flight path; there is a deflection angle between the two.

Generally, calculating an aircraft's yaw angle requires a flight ruler, also known as a navigation slide rule. Calculating this manually would be extremely cumbersome.

Moreover, since the wind direction and speed are not fixed, the deflection angle will keep changing. Even if there is a flight gauge, it may not be possible to calculate it in time, let alone the fact that Xu Xian does not have a flight gauge.

However, the drift angle is only one aspect. Due to changes in speed, the estimated contact time between the aircraft and the obstacle also changes constantly. Xu Xian needs to determine when to take evasive action based on the changes in speed, without the slightest deviation.

In this environment, Xu Xian did indeed possess all the data to determine the aircraft's location, but each data point contained a vast number of variables. The sheer number of variables resulted in an astronomical amount of computation throughout the process, yet Xu Xian attempted to calculate it mentally.

This is like an ant trying to shake a tree; it's laughable and shows a lack of self-confidence!

Xu Xian closed his eyes slightly and let out a long breath, though the sound of his exhale trembled slightly. He paused, then, instead of continuing to speak to the captain, raised his eyelids and whispered to Meng Zili, "Notify air traffic control to tell Guangdong Air Force not to retrieve terrain data."

"Captain Xu, are you really going to fly by yourself? Or should we apply for fighter jet escort? It's not far from our airport, we can get here quickly," Meng Zili advised. To be honest, he was also worried and incredulous about what Xu Xian was about to do. To be able to calculate the evasion route just by mental calculation was something only a god could accomplish.

"The fighter jets are not as good as us at low speeds. Their aircraft are small and have limited resistance to turbulence. Wouldn't it be more dangerous to let them navigate between valleys?" Xu Xian said.

He had considered having a fighter jet lead the way, since many fighter jets are now equipped with terrain-avoidance radar, and as long as the terrain isn't too complicated, the lead passenger plane should be able to navigate through the valley.

But the wind is too turbulent now, and fighter jets are relatively small. The same turbulence might be nothing for a large commercial airliner, but it could be quite difficult for a fighter jet to maneuver. Moreover, since it's for navigation, the fighter jet will definitely be flying at low speed, and fighter jets are inherently less efficient at low speeds than at high speeds. Doesn't this add even more danger?

If fighter jets were to come and lead the way, it's entirely possible that the fighter jets would be the first to crash.

"But, Captain Xu," Meng Zili wanted to say something more, but Xu Xian stopped him with a shout: "Execute the order!"

Meng Zili's body stiffened, he gave Xu Xian a deep look, and finally said heavily, "Yes!"

Xu Xian slowly gripped the steering wheel with his right hand, and the terrain display in his mind gradually became clearer. Slowly, Xu Xian even began to hear his own heartbeat, like the beating of a drum, responding to the surging power.

At this moment, the world seemed to fall silent, as if waiting for Xu Xian's performance.

"What did you say? You don't need the terrain data? Why not?" The duty officer, hearing Meng Zili's words, couldn't hide his disbelief: "Without the terrain data, how are you going to fly?"

Meng Zili looked at Xu Xian in front of him and said softly, "Captain Xu, come fly."

"Team Leader Xu? Xu Xian! Nonsense! How can he fly? Without terrain data, how can he avoid obstacles? How can he fly?" The duty officer nearly roared at Meng Zili, "What are you doing? Terrain data is available, why aren't you using it?"

The duty officer's shout echoed through the small cockpit via the loudspeaker, disturbing Xu Xian, who was rapidly calculating in his mind, causing him to tremble slightly. Meng Zili keenly noticed Xu Xian's change, gritted his teeth, and directly shut down the VHF loudspeaker, eliminating any external interference for Xu Xian.

Even though the captain on the left was extremely anxious, he dared not disturb Xu Xian any further, because at this point, the plane could crash into a mountain any second.

The duty officer yelled a lot into the microphone, but there was no response from the other end of the radio. Frustrated, the duty officer slammed the microphone onto the table.

"They've all gone mad! They've all gone mad!" the duty officer cursed. "Wherever that brat Xu Xian is, nothing stays mad."

Beside him, his assistant whispered, "Director, what about the terrain data?"

The duty officer's temples throbbed. After a moment's thought, he said resentfully, "Notify the military to suspend the retrieval of terrain data."

"What if the military asks for the reason?"

The duty supervisor glared at him: "Tell the truth, I don't care anymore, let them go crazy on their own!"

The Letu Operations Control Center has just received a message from the Huacheng Control Room that a portion of terrain data packets will be transmitted over, and then they will upload them to flight 5641.

Since receiving the news, the security manager has been constantly monitoring the situation, eagerly awaiting the arrival of the terrain data package. However, after waiting for a while, there was still no sign of it.

The plane is now a single-engine aircraft, but it's in a typhoon, a life-or-death moment where every second counts. Why is the traffic control in Huacheng so slow?

The Huacheng control room didn't mention that the terrain data package came from the military, leading the Letu operations control center to assume that the Huacheng control room had the terrain data! They also couldn't understand why the control room would have terrain data.

The security manager, who was nearing the end of his patience, finally couldn't hold back any longer and was about to send someone to contact the Huacheng control room. Just then, a staff member came over to report: "Brother Wang, we've received a message from Huacheng control that the terrain data will not be transmitted for the time being."

"Not transmitting it anymore? Why not? How are the crews supposed to fly?" The safety manager was dumbfounded. How could they change their minds so easily?

When he contacted the Huacheng control room just now, he already knew the status of flight 5641. Without terrain data, how can the crew fly?

The security manager waved to the staff: "Go and ask Huacheng what's going on."

"Brother Wang, it's not a problem with air traffic control, it's a request from the flight crew." The staff member had casually inquired about the specifics when receiving the message from control room earlier.

The safety manager, who was on board, gasped, "Are they crazy?"

In fact, not only was the security manager shocked, but even the staff member found it hard to accept: "Brother Wang, to be precise, it was Xu Xian who requested it."

The security manager, Xu Xuxian, was trembling, his blood pressure skyrocketing, and he almost fainted from anger. He said in a trembling voice, "Connect me to Star Travel Control."

In the cockpit, apart from the rumbling of the engine, there was only the heavy breathing of the three people.

The captain and Meng Zili were practically holding their breath, afraid of disturbing Xu Xian's mental calculations. Outside the windshield, the strobe lights flickered intermittently; otherwise, visibility was virtually zero. The rain was so thick that the outside world was completely invisible to the naked eye.

The captain had initially hoped that as they flew closer, they might be able to see the outside situation with the help of a faint light, which would aid in clearing the obstacle.

However, the dark clouds completely covered the sky, and the moonlight could not penetrate the clouds at all. Without the help of moonlight, it was pitch black outside, and the aircraft's evasive maneuvers were now entirely dependent on Xu Xian's control.

Xu Xian remained silent, ignoring everything outside and focusing his attention on the various instruments. He couldn't influence the wind direction and speed; all he could do was control the airspeed to maintain relative stability through pitch and throttle, thus eliminating one variable he needed to calculate.

However, it was still within the typhoon area, especially at the edge of the typhoon's eye where the winds were strongest. Even though the terrain reduced the wind force, the aircraft was still difficult to control when actually flying within it.

Because the aircraft only has one power source, its speed can only be maintained at a smooth speed of 250 knots. Moreover, due to the lack of power limit, Xu Xian cannot quickly correct the aircraft's state with sufficient thrust as he could with two engines.

In fact, it wasn't just about calculating the relative position of the aircraft to obstacles; Xu Xian also had to exert tremendous effort in aircraft control. The external turbulence was extremely severe, and to maintain relative speed stability, Xu Xian needed to make significant adjustments to the throttle. If both engines were functioning properly, the amount of throttle adjustment Xu Xian needed wouldn't be as large, but in single-engine mode, achieving the same effect required a much larger throttle adjustment. In single-engine mode, the throttle and rudder inputs are linked. Increasing the throttle requires corresponding rudder inputs, and decreasing the throttle requires decreasing the rudder inputs, otherwise the aircraft will sideslip. Whenever the aircraft sideslips, the yaw angle changes. Moreover, Xu Xian couldn't calculate the yaw angle changes caused by sideslip due to a single engine in the current environment.

Therefore, Xu Xian had to always ensure that the aircraft's sideslip indicator was in an absolute zero sideslip state. No matter how the throttle was moved, the rudder input had to keep up with it without any delay.

The captain watched Xu Xian's actions from the side, and his worldview was almost completely shattered. Due to the extremely strong external turbulence, Xu Xian was constantly switching between full thrust and idle speed when adjusting the throttle of the second engine, a range of adjustments that was extremely rare.

However, even with such a large throttle adjustment, Xu Xian was able to keep up with the rudder adjustment immediately. Or to be more precise, Xu Xian's rudder and throttle adjustments were perfectly synchronized.

In a single-engine configuration, to eliminate sideslip, you need to increase rudder input when accelerating and decrease rudder input when decelerating—this is a straightforward principle. However, there isn't a linear correspondence between these two; there's only a general connection. Therefore, many pilots in single-engine situations often fail to perfectly synchronize throttle and rudder adjustments. This is because pilots don't know the exact amount of rudder adjustment needed; they only have a general feel for it and then judge whether the adjustment was too much or too little by checking the sideslip gauge or steering wheel deflection.

However, none of this happened to Xu Xian. Every time the throttle was adjusted, Xu Xian was able to accurately input the steering input, and the sideslip gauge remained virtually unchanged throughout, which was almost like a miracle.

For Meng Zili, who was sitting in the back seat, what he saw today would be forever etched in his mind, something he would never forget. He had never imagined that one person could handle such a huge amount of calculation while maintaining the precision of aircraft control.

He had heard of Xu Xian's reputation before. His single-handedly annihilating over a dozen fighter jets of the Guangdong Air Force's 4th Division was an unprecedented feat. Even now, Xu Xian's name is still widely known throughout the Guangdong Air Force.

As the younger brother of Meng Ziyang, a top ace pilot in the Guangdong Air Force, Xu Xian naturally paid extra attention to him, as he was also a talented pilot. Compared to Xu Xian, who was just beginning to make a name for himself in the military, Xu Xian was already a well-known figure in civil aviation.

Previously, Meng Zili had no idea what kind of tricks civil aviation could perform, but what he saw today was truly astonishing, like a god descending to earth.

Xu Xian's entire body was tense at this moment. His face and neck were beginning to flush slightly, a sign of rising blood pressure and dilated capillaries. His blood pressure was now above normal, like someone who had just engaged in strenuous exercise; a noticeable sweat stain was visible on the back of his clothes. Beads of sweat were constantly seeping from his forehead, cheeks, and neck. He was like a taut rope, ready to snap at any moment.

However, even under this immense pressure, Xu Xian was still able to maintain a high level of mental arithmetic ability. His eyes were constantly moving in small increments as he compared various data points and continuously updated his flight direction.

Slowly, Xu Xian felt a surge of heat rush to his head, and a warm liquid slid down his nose, flowed over his lips, and finally dripped onto his pants.

When the captain saw that Xu Xian had a nosebleed, he was horrified and prepared to wipe it away for Xu Xian, but Meng Zili grabbed him.

At this moment, Xu Xian was on the verge of collapse. The enormous amount of computation had filled his brain, and any excessive external disturbance would interrupt his calculation process. Once this calculation process, or rather the state of calculation, was interrupted, it was like a deflated balloon that could never be put back together.

Meng Zili pressed down on the captain's hand and shook his head at him.

Now is the most crucial time; we cannot afford to lose everything we've achieved so far.

However, at that moment, with a violent tremor, as if breaking through the last barrier, the originally dark space suddenly burst into silvery-white light, and the bright moonlight shone down, enveloping Xu Xian's face.

In the eye of the typhoon, there was not a single wisp of cloud, let alone wind or rain. Turbulence was nowhere to be found, and the bright moon hung high in the sky. It was like a secluded paradise, the most tranquil place in the entire typhoon system.

The moment Xu Xian squinted and saw the moon, he knew he had crossed the edge of the most dangerous eye of the typhoon. Suddenly, he felt his eyelids were so heavy that he couldn't lift them at all. Once his tense nerves relaxed, an overwhelming sense of fatigue instantly overwhelmed Xu Xian.

Before Xu Xian could say anything, everything went black, and he fainted.

(End of this chapter)