The huge airflow hit the plane, and the plane immediately entered an incredible state. As Xu Cang said before, the wind speed at the outskirts could exceed 500 kilometers per hour, and even Xu Cang had never encountered such a strong airflow.
Xu Cang's mind quickly recovered after the initial impact of the airflow. He was a human being, so he would naturally have an instinctive stress response, but Xu Cang was not an ordinary person. Moreover, he was now in a peak state that surpassed any previous period, and his reaction speed was unparalleled.
Many pilots have encountered strong winds and turbulent weather, but few people have encountered terrifying air currents with speeds exceeding 500 kilometers per hour.
You know, many large passenger planes only travel at a speed of 800 kilometers per hour.
Actually, 500 kilometers per hour of airflow is fine if it is relatively stable. Because at high altitudes, aircraft may encounter relatively strong high-altitude winds, and it is not uncommon for the speed to exceed 100 knots.
But the problem is that the current airflow is not only extremely strong, but also very, very unstable. Xu Cang glanced at the wind direction and speed display on the navigation page. The wind direction kept changing between 010 and 150 and never stopped changing, but the general direction was still from west to east.
The wind speed displayed changes wildly from two hundred to three hundred knots, with a very large span.
In fact, this degree of wind speed change is very dangerous. Of course, the flight altitude is not high at the moment, and there is still a little speed margin. If it is at a high altitude, the speed space is relatively small, and the external air flow speed changes so much, the aircraft will only cross the overspeed and stall warnings.
So, in a sense, Xu Cang's approach was relatively good, or fortunately.
The angle of entry of Xu Cang's plane was from north to south, almost vertically, which made this violent airflow just a crosswind for the plane.
At low altitude and low energy, aircraft are very afraid of crosswinds, because at that time the aircraft needs to be aligned with the runway and maintain the flight trajectory in a relatively stable environment. If the crosswind is too strong, the approach will easily fail.
However, at a slightly higher altitude, the aircraft does not need to approach, and there are no other aircraft in the no-fly zone, and there is no need to worry about traffic conflicts. As long as the aircraft is not smashed, it is acceptable.
Obviously, such a huge degree of freedom makes Xu Cang feel more comfortable than the various restrictions during the approach.
The reason why vertical cutting is better than straight cutting is that the key lies in speed.
Even if the airflow direction and speed vary greatly, the general wind direction and wind speed are within a certain range. Therefore, the value of the component in the flight direction will not change too much due to the vertical angle.
But if you go directly into the wind, the combination of the two can increase the aircraft's airspeed from more than 250 knots to nearly 500 knots in an instant.
Safety margins are taken into consideration when the aircraft is designed. For example, in the case of small, accidental speeding, no special measures are generally required. It is only necessary to record the duration of the speeding and the maximum speed exceeding the limit in the maintenance book.
In daily flight operations, both the company and the civil aviation management agency have a significantly higher tolerance for speeding than for stalling. At least under the same circumstances, the penalties for the two are obviously different.
However, a high tolerance for speeding does not mean that you can speed at will. Usually, the maximum speed of an aircraft is around 400 knots, and there is not much difference between different models. Generally speaking, speeding within a dozen knots is tolerable, but exceeding nearly 100 knots is not tolerable.
The reason for setting a speed limit is to protect the aircraft structure. If the aircraft speed is too high, the impact on the aircraft structure will be very large. Exceeding the speed limit by 100 knots is unacceptable regardless of the aircraft model. With such a large speed limit, the aircraft may even disintegrate.
If the wind is tailwind, the aircraft speed will drop sharply, and it may enter a stall instantly, which is usually very dangerous. Moreover, the wind speed is too high now, and if the wind is tailwind, the indicated speed may even return to zero, which is obviously extremely terrifying.
In general, whether it is overspeeding and disintegration, or stalling and returning to zero, the danger is far greater than the current situation. At this altitude and crosswind, most of the danger lies in the change of the aircraft's attitude, and this little danger is at least controllable for Xu Cang.
That’s right, this strange change in state is controllable by Xu Cang.
After a very brief moment of surprise, Xu Cang's mind immediately came to its senses. With his unparalleled reaction ability, he immediately analyzed the current situation. Due to the impact of the huge left wind, the plane began to roll to the left uncontrollably. At the same time, the vertical tail was impacted by the airflow from the left, and the tail began to move to the left, thus driving the nose to the right.
If that were the case, the aircraft would only have rolling and yaw state changes, rather than the terrifying and complex phenomena that they are now. Therefore, why wind tunnels can never completely replace flight tests, because the complexity of airflow in nature can only be fully simulated by human instruments.
"Is the headwind increasing?" Xu Cang smiled slightly, already understanding all the changes in the airflow.
Although the airflow encountered by the aircraft is mainly westerly, the southwest wind accounts for a larger proportion of it, which causes the aircraft to be continuously affected by the headwind. Moreover, even if the wind weight is small, it can be too strong, so the intensity of the decomposed headwind will also be very high.
Remember, rolling is not the same as rolling, and similarly, rolling and yaw will not cause a rollover even if they occur simultaneously. To cause a rollover, the aircraft attitude needs to increase, and it needs to increase significantly.
For example, if you want to overturn something, you often lift it up first and then move it to the side.
Due to the huge increase in headwind, the performance of the aircraft became extremely strong in a short time, which caused the aircraft to begin to lift its head involuntarily.
However, this alone is not enough to cause a rollover. The final condition for a rollover is a sideways slide!
Why did Richard react so violently when he noticed the plane was skidding?
It is because once the sideslip occurs, and it is not artificially generated, the aircraft becomes unstable. In fact, Richard does not understand why the aircraft will have sideslip. Sideslip only occurs when the thrust is unstable or the stalling spiral occurs.
Because of the presence of the yaw damper, the aircraft can correct its sideslip more automatically.
Even though the aircraft was in a very complicated state, it didn't seem to be in a side-slip condition. The changes in altitude and speed also confused him. The wind decomposition was already displayed on the CDU progress page on his side.
The CDU showed that the aircraft was basically facing a headwind, so the aircraft speed should be rising instead of falling like mercury.
But judging from the airspeed indicator, the airspeed could no longer be stopped and began to plummet.
And that height!
In fact, for an experienced pilot, he can roughly judge the aircraft's climbing rate at the moment by the aircraft's pitch attitude. Moreover, Richard turned on FPV, which made it more obvious what the aircraft's status was.
Although it is always changing, the aircraft's attitude is roughly maintained between two and three degrees, which is a standard level flight attitude in a cruising environment. Even if it is not level flight, it is impossible to drop significantly.
In addition, from the FPV point of view, the display is almost consistent with the horizon, which means that the aircraft should not be descending.
The reason why the pitch attitude of the aircraft is different from that of FPV is because of the existence of the angle of attack.
For example, the pitch attitude of an aircraft is two degrees, which means that the aircraft is slightly tilted up, but in fact, in the trajectory, the aircraft is flying level. Therefore, it is not what laymen consciously think that the aircraft is flying level when the pitch attitude is zero degrees, but the aircraft is flying level when the FPV is zero degrees.
But now, the aircraft's pitch attitude is two to three degrees, the FPV attitude is close to zero degrees, and the vertical table shows a huge descent rate of five thousand feet per minute, which is simply beyond Richard's cognition.
It is precisely because Richard is familiar with the principles of flight that he has such doubts. Otherwise, a pilot with only a superficial understanding would not be able to think so much and naturally would not be able to understand the horror of it.
"The plane is skidding. If it flips over, it will go into a spin!" Richard shouted.
There are many explanations for what a spiral is, but in Richard's eyes, it is a stall plus a sideslip. As long as the two are present, the conditions for forming a spiral are met.
At this moment, the speed of the plane is already very high. If it goes into a spiral, the speed of the plane will increase exponentially, and it may not be able to sustain two turns.
Xu Cang pressed the pressure plate to the right again, but this operation to suppress the roll seemed to have no effect. The wind was too strong and the ailerons alone could not suppress it.
Richard is not afraid of a spiral. As he is also a stunt pilot, he is confident that he can stop the spiral in the first turn, but that does not mean he wants to enter a spiral under the current circumstances.
The airflow environment outside is too complicated now. Once entering the spiral, who knows what kind of incomprehensible situation will be encountered. At least the current situation is incomprehensible to him.
Richard broke out in a cold sweat when he saw that Xu Cang's attempt to press to the right was fruitless. The plane was rolling and could no longer withstand the impact of the strong wind.
At this moment, the headwind suddenly increased, the nose of the aircraft began to rise uncontrollably, and the aircraft attitude instantly exceeded five degrees. Due to the excessive attitude, the stall limit indication on the CS300 appeared on the attitude instrument.
However, even with such a large attitude, the aircraft's descent rate was only slightly reduced.
Xu Cang immediately pushed the stick, trying to push the plane's attitude downward. The attitude was too big and was about to exceed the critical angle of attack.
But this headwind was too strong, and the performance improvement it brought to the aircraft was unimaginable. It was like a wild horse that had broken free from its reins. Xu Cang was simply unable to control this muscular wild horse with the reins.
The aircraft's attitude only slightly decreased under Xu Cang's push stick, and then continued to rise uncontrollably, and was about to exceed the stall limit indicator.
"We're really going to stall!" Richard shouted suddenly.
Why did Richard say the word "really"? Because he was somewhat aware that the airspeed and altitude might not be accurate, otherwise it would be impossible to explain many contradictory data. Although he could not completely determine the reasons for the unreliability of airspeed and altitude, he had some rough guesses in his mind.
Since airspeed is unreliable, the stall warning derived from airspeed may also be false.
So, before this, although Richard was frightened, he was not too anxious or lost control.
But now it is different. The airspeed may be false, but the pitch attitude of the aircraft will not be a problem and can be trusted.
The unreliable airspeed checklist for almost all aircraft types will state that the aircraft attitude can be trusted.
The stall warning derived from airspeed is false, but the stall warning derived from attitude is not false. You know, the difference between the pitch attitude of the aircraft and FPV is basically equal to the angle of attack.
The essence of an aircraft stall is never the speed or attitude, but the angle of attack. As long as the critical angle of attack is exceeded, the aircraft will stall.
But now the difference between the aircraft's pitch attitude and the FPV attitude is getting bigger and bigger, which means that the aircraft's angle of attack is getting bigger and bigger, and the distance to stall is getting closer and closer.
If the plane stalls and skids at this moment, and the wind blows a little, it will roll over and then instantly switch to a spiral with almost no stagnation.
"Why is there sideslip? There shouldn't be sideslip!" Richard can accept and understand many things, but he cannot accept and understand the existence of sideslip.
"Because of the poor lift!" Xu Cang said calmly, not looking very anxious.
"What?" Richard was stunned: "How can there be a lift difference? It's not a wing..."
However, Xu Cang no longer had time to answer Richard. If he couldn't get the plane back to level flight, he had to find another way.
Xu Cang directly changed the right pressure to the left pressure. The plane was originally turning to the left, and without the aileron suppression , it was like a leak, and the slope increased instantly.
Moreover, Xu Cang not only did not stop it, but instead escalated the situation and added fuel to the fire, continuing to press the stick to the left in the direction of the plane's roll.
"What are you doing!" Richard could instantly understand Xu Cang's operation from his body feeling, but before he understood why Xu Cang was so crazy, he heard Xu Cang chuckle: "It's okay, just changing the direction, sit tight."
"Sit... sit tight?" Richard didn't actually understand what Xu Cang wanted to do, but he could taste something from this sentence.
Richard thought of Xu Cang's unpredictable control ability and his wild imagination, so he didn't ask any questions and immediately tightened his seat belt.
At the moment when Richard fastened his seat belt, Xu Cang pressed the side stick, and relying on the impact of the airflow, the bank of the aircraft increased all the way to ninety degrees. The cockpit was filled with the sound of bank warnings.
At the same time, Xu Cang pushed the left rudder forward, slightly straightening the nose of the plane and eliminating some of the sideslip.
"Stop pressing, that's enough, that's enough!" Richard's body was almost parallel to the ground. He stretched his throat and shouted, wanting Xu Cang to be more gentle.
With such a strong crosswind, the aircraft doesn't need ailerons. Just the wind can cause the aircraft to generate a huge rolling moment. If ailerons are added, it will appear too rough.
Richard is not a young man and his heart can't take it.
"If we don't turn faster, the plane will fall." Xu Cang was calm and composed, and there was even a hint of sarcasm and ease in his words, as if he didn't take the current situation seriously at all.
Richard was startled: "What fell?"
"Literally!" Xu Cang chuckled and said, "Hold on to the seat."
Richard's face froze: "You..."
Before he could finish his words, the plane's bank angle had reached nearly ninety degrees, and the airflow could not directly impact the vertical tail. The yaw moment applied to the plane rapidly decreased, allowing Xu Cang to straighten the plane immediately.
However, this is not the end.
When the plane's bank approached ninety degrees, Xu Cang pressed the stick without any pause, and the plane turned over directly under the dual effects of the ailerons and airflow.
"Xu Cang, push the pole, push the pole!" Richard is indeed a wise old man. His mind is still clear at this time, and he even has the energy to remind Xu Cang.
But does Xu Cang need to be reminded? He is omniscient and omnipotent.
At the moment when the plane was almost upside down, Xu Cang pressed the left stick and pushed it forward at the same time, and the plane did not show any sign of falling.
However, this state only lasted for a moment. The left rolling torque was too great, and the plane did not stop for a moment. Instead, it did not really continue to fly backwards, but just went straight forward and turned right again in an instant.
After passing the apex, Xu Cang's left stick pressure action remained unchanged, but as the plane continued to roll, he gradually and gently switched from pushing the stick to pulling the stick. The control action was done in one go without any obstruction.
However, when it was about to change to level flight, the plane suddenly seemed to lose its strength and the nose began to drop uncontrollably.
"It's a tailwind!" Richard immediately realized that after the plane rolled to the left and partially turned left, the nose of the plane began to shift to the left. In this way, the wind encountered by the plane instantly turned into a strong tailwind, and the performance of the plane decreased sharply.
After thinking about this problem, Richard immediately shouted: "Don't bring a pole!"
The huge tailwind in this situation cannot be suppressed by pulling the stick. If you force the stick to pull, it will aggravate the stall of the aircraft.
However, Xu Cang had anticipated these things. From the moment he turned to a tailwind, Xu Cang immediately switched from holding the stick to pushing the stick, increasing the speed at the cost of losing altitude to prevent the aircraft from entering the red zone.
However, this is obviously not enough. The tailwind is too strong and the aircraft is not at a high enough altitude, so it is impossible to maintain this abnormal state.
Therefore, Xu Cang kept the left stick pressed, and the plane rolled to the left after leveling off, and in an instant it was out of the tailwind area created by the cyclone. However, this time it didn't need to roll to the point of inverted flight. After leaving the tailwind area and the nose of the plane stopped its downward trend, Xu Cang reduced the plane's bank angle, increased the throttle, and released the thrust handle: "Switch to control."
"Hmm?" Richard was stunned for a moment, but didn't say anything. He took over the thrust handle and side stick naturally: "Take over the control."
At this moment, the plane has left the cyclone area. Although it is still very bumpy, it is much better than the previous thrilling state. Richard can now fully control it.
However, due to the continuous rolling to the left, the plane turned almost 180 degrees and began to fly back.
"Fly forward a little, and then hover on the spot." Xu Cang said.
"Yeah." Richard looked at the airspeed and altitude. At this time, the two altimeters of the aircraft had even returned to zero, and the values ​​of the airspeed indicator were also very different. The left one was constantly decreasing and was approaching the red zone.
Once the aircraft decreases to the red zone, the stick shaker warning will be triggered.
"The Pitot tube and the static pressure port are blocked?" Richard frowned and looked at the aircraft thrust and attitude. He remembered the standard thrust and attitude values ​​for all altitudes and stages. Under the standard thrust and attitude values, it was impossible for the aircraft to reach such a speed.
Moreover, the altimeter returning to zero directly obviously indicates that there is a problem with the static pressure port of the aircraft. The abnormality of the airspeed indicator also indicates that there may be a problem with the pitot tube.
Richard had guessed about this situation before, but he didn't expect the ice to be so fierce.
It is almost certain that the wind, snow and ice blocked the Pitot tube and static pressure port, which caused the abnormal altitude and speed.
"Warming the probe doesn't work?"
The aircraft has good protection for the detectors, and naturally takes into account the ice accumulation of the probes. Therefore, as long as the flight is normal, all detectors, including the pitot tube, will be electrically heated to prevent ice clogging.
Richard looked up at the probe heating panel and found that the switch position was correct and there was no indication of abnormal heating function. In other words, the snow outside had dropped to the point where electric heating was useless.
"The intensity of the ice accumulation has completely exceeded our expectations." Xu Cang's left hand fingers kept tapping on the top of the left side stick. This is not a good habit, but it also reflects from the side how helpless and anxious Xu Cang is.
"It's not just ice accumulation, the airflow is too strong." Richard thought about the situation of the plane just now, and he was still frightened: "As long as it enters from the outside, it will inevitably encounter a positive crosswind. The plane can't withstand such a strong positive crosswind. I'm afraid that only a big plane like a 747 can withstand it. This plane is too small."
Ice accumulation and air currents, these two almost unsolvable problems stood in Xu Cang's way like a natural chasm.
Xu Cang had tried his best to prevent ice from accumulating on the plane, but it was of no avail. The airflow exceeded the aircraft's handling limits and could not be suppressed at all.
It was because Xu Cang was bold and careful that he flipped the plane over and finally got out of the air flow area. If he had stayed in it for a while longer, no one knew what would have happened.
With the skills of a pilot of Richard's level, he didn't care about the situation where the altitude or speed was unreliable. He was already familiar with the CS300 manual. The standard thrust values ​​and attitudes for all stages of cruising, descent, and approach were all clear. He didn't even need to look at the speed, and he also had a way to deal with the altitude.
But the situation of ice accumulation and strong air currents was beyond his ability to resolve. This was a problem beyond the performance of the aircraft and even the gods could not help.
"Although the probe blockage is not a big problem for us, in this situation, how about we return home first?" Richard really couldn't think of any other solution: "Let's take a long-term view?"
Xu Cang shook his head: "No! The landing window is only ten to twenty minutes. If you miss it, you won't be able to land."
"But now it's not a question of whether we want to or not, but a question of whether we can." Richard licked his lips, which was an obvious sign of anxiety.
"Contact control and tell this station to have Bombardier upload the latest satellite cloud images." Xu Cang said.
Bombardier was represented in Munich, and the CS300 can share data via satellite, but most airlines don’t use this feature.
"What are you going to do?"
“Determine whether the window period is approaching.”
Richard took a deep breath and said, "So what? We just can't get in. This is an objective fact. I raised this doubt when we were on the ground."
"I said I would let them live." Xu Cang pursed his lips and said, " I won't break my promise."
"But..." Richard didn't know how to persuade Xu Cang: "You have to consider the reality...,..."
Before Richard finished speaking, Xu Cang suddenly asked, "How is your heart?"
"Ah?" Richard was stunned: "Heart?"
"Yes, how is your heart?" Xu Cang repeated.
"I'm... fine."
Richard is a pilot and is airworthy, so naturally there is no major problem with his heart.
But, he is old after all, and is definitely not as good as young people.
But from Xu Cang's words, Richard smelled a hint of uneasiness: "You...what are you going to do?"
Xu Cang smiled and said, "I guess we are going to do something very... exciting."