In the Jianchuan control room, Di Qingquan turned around suddenly and looked at Luo Yong: "There is no circling approach procedure at Yulong Airport, right?"
Although Di Qingquan is the chief engineer of the General Administration, it is impossible for him to know the situation of all airports in the country. What's more, the southwest region has a relatively small area under its jurisdiction, so he knows even less about the situation.
However, there are only a few airports in China that implement visual circling approaches. Logically, Di Qingquan could even recite the list of all these airports, but no matter how hard he tried to recall, Yulong Airport did not seem to be included.
Circling approach, that is, visual circling approach, also known as reverse approach, means intercepting the localizer from the runway opposite to the landing runway, and then maintaining continuous visual sight of the runway at a specific altitude within the airport safety area, bypassing the entire airport in accordance with prescribed procedures, and turning the landing direction to the expected runway.
Of course, different directions of the same runway is the most common form of visual circling approach. In some special procedures, the approach and landing can be offset on different runways that are at an angle, that is, on a runway, the localizer is aligned without pressing the APP, and then the approach is turned to another completely different runway for landing. This situation basically occurs at airports where the two runways are at an angle rather than parallel, but this type of airport is also relatively rare.
Due to the existence of the circling approach protection zone, the clearance conditions around the airport must be sufficient to complete visual flight within a specific range. The scope of the circling protection zone is different in the FAA and ICAO standards. The ICAO standard is adopted in China. During the circling period, the aircraft does not establish a landing configuration, but flies in flaps 5, and the speed can be controlled at 180 knots. At this speed, the radius of the circling area of ​​the circling approach protection zone from the runway entrance should be 4.2 nautical miles.
It is particularly noteworthy that the radius protection zone of the circling area centered on the runway entrance is not just centered on the entrance of the landing runway, but a circle with a radius of 4.2 nautical miles centered on the entrance of the landing runway and the entrance of the runway to be aligned. All the airspace within the circle, including the overlapping part, is the circling protection zone during the visual phase of the approach.
Regardless of the reason, as long as the aircraft leaves this circling protection area, it is considered an approach failure. Because the visual circling approach usually cuts into the final leg and lands in one go after the third leg is completed, which is extremely challenging for the pilot's visual judgment ability. Because basically when cutting into the final leg, the aircraft is very close to the runway, and there is not enough straight-line distance to correct the roll and pitch. As long as the pilot does not control the bank well, does not turn to the final leg, or there is a problem with the control of the descent rate, when cutting into the final leg, there is a problem with the altitude, then it is almost necessary to go around.
At the same time, the go-around method of circling approach is also extremely complicated. Once you go around, you cannot go around in the direction of the landing runway, but should turn back to the go-around direction of the runway you started to align with and go around according to the go-around procedure of that runway.
However, there is a lot of knowledge about how to turn to the go-around procedure of the runway that is initially aligned, especially when making a visual circling approach to an angled runway.
The procedures were complicated and the control was extremely difficult, so problems often occurred during visual circling flights, and there were even several times when flight accidents almost occurred.
All domestic unsafe flight incidents will eventually be reported to the General Administration, and the responsible reviewers are basically the Aviation Safety Department and the Flight Standards Department. The Aviation Safety Department is headed by Li Lin, and the Flight Standards Department is almost responsible for reviewing unsafe flight incidents. Therefore, he deeply understands that the visual circling approach method itself has risks, so the domestic authorities are very cautious when approving and implementing relevant procedures.
Airports that can implement visual circling approaches usually have good surrounding clearance conditions, at least within a radius of ten kilometers. However, in Di Qingquan's impression, the surrounding clearance conditions of Yulong Airport do not seem to meet the requirements.
As expected, Luo Yong nodded after a little thought: "I also remember that Yulong Airport does not have visual circling approach. No, in the province, except Jianchuan Airport, all other civil airports should not have visual circling approach procedures. What on earth is Xu Cang going to do?"
Mo Shangyun's face also looked very bad. He had been flying in the southwest for nearly 30 years. Not to mention civil airports, he had also flown to military airports when he served in the Air Force.
Luo Yong was too conservative. Not all civil airports except Jianchuan Airport, but all military airports did not have visual circling approaches. The whole province was full of mountains and ravines. The only large plain was given to the provincial capital Jianchuan. Therefore, Jianchuan Airport had good enough air clearance conditions to implement visual circling. The other airports in the province were all surrounded by mountains. Where could they have such a good air clearance environment?
"Xu Cang, what on earth are you thinking about?" Mo Shangyun roared in his heart, since he had placed his hopes on a program that did not exist at all.
Director Liu knew that Jianchuan Airport had a visual circling approach procedure, but since the procedure was released, Jianchuan Airport has never implemented it. This is written in the Jianchuan control instructions. Unless in an emergency, the visual circling approach procedure is not used in principle. This shows that the controller is well aware of the risks involved in the visual circling approach procedure.
"What should we do now?" To be honest, Director Liu had never expected things to develop to this point. However, Xu Cang was the only one on the plane, and it would be useless for them to just shout here. Everything was done according to Xu Cang's final wishes.
However, he even doubted whether Xu Cang could still think normally, otherwise why would he invent a program out of nothing? Could it be that in the harsh environment of the broken windshield, Xu Cang's consciousness had begun to blur?
In fact, this is not impossible. The oxygen content is low at high altitudes, and under strong airflow, it is even more difficult for people to breathe due to the decrease in air pressure. In this case, Xu Cang may really lose his normal thinking ability.
If this is true, it would be the worst outcome.
Di Qingquan's face became increasingly gloomy, his mind constantly working, and finally he said in a deep voice: "Ask the search and rescue team to send a helicopter to Yulong Airport!"
Director Liu was startled: "You know that the search and rescue team only has two helicopters, right? Although the earthquake damage in Yulong City is not very serious, it is still a great pressure for the search and rescue team with only two helicopters. You took away one..."
"Xu Cang must not be in any danger!" Di Qingquan lowered his head: "No matter what, Xu Cang's safety should be given priority. He deserves this treatment. Is it inconvenient for you to contact the fire department? Then I will do it myself."
The provincial search and rescue team is composed of the Provincial Fire Brigade, the Provincial Earthquake Search and Rescue Center and the Emergency General Hospital. However, the front-line search and rescue air force only has two helicopters. For this southwestern province, two helicopters are indeed stretched, but there is nothing that can be done about it.
Director Liu frowned and said, "Forget it, you better keep quiet. I'm more familiar with them, so I'll talk to them."
Di Qingquan let out a long sigh. Now, there was only the noisy sound of wind and rain in the loudspeaker. There was no sign of Xu Cang at all. He didn't know what Xu Cang's condition was at this moment.
…
At this moment, Xu Cang felt like he was in an ice cellar. The plane had already dropped to about 5,100 meters. Although this altitude was not as deadly as 30,000 feet, it was still raining outside, and the strong wind blew the rain back in, soaking Xu Cang's whole body almost instantly.
According to the report from Yulong Airport, hail has been seen falling, which also means that the thunderstorm cloud on the fifth side is filled with a large number of supercooled raindrops.
So-called supercooled water, that is, water that remains liquid at temperatures below zero, remains liquid below the freezing point because it is too pure and lacks the condensation nuclei required for condensation.
However, once these super-cold raindrops touched Xu Cang's clothes, they condensed into ice slag on his clothes at a speed visible to the naked eye. However, in just half a minute, Xu Cang's clothes, arms, and even eyelashes were covered with ice particles.
Xu Cang let out a breath softly. He knew that he had to land as quickly as possible, otherwise, hypothermia alone would kill him.
In fact, it doesn't need to be severe hypothermia. Just moderate hypothermia will cause his muscles to twitch uncontrollably, his ability to think will be lost, and his coordination will almost disappear. In this case, no one can continue to control the plane normally, and only death will await him.
In the chaotic sound of wind and rain, I could faintly hear the warning sound of the cabin altitude being too high. It all happened so quickly that at the moment the windshield broke, it took a while for the cabin altitude to rise to more than 10,000 feet.
He slightly opened and closed his right hand, and found that it was not completely frozen and could still move. Xu Cang lowered his head to avoid being directly hit by the wind and rain. He did not immediately pull the plane up, but directly switched his left hand holding the throttle to the steering wheel to control the plane to keep it flying level, while freeing up his right hand, which he put down and kept groping above the storage box on the right.
The wind was strong and the rain was heavy. Even though Xu Cang lowered his head, he still had difficulty opening his eyes and could only rely on touch. However, his right hand was almost numb due to the cold, and in a panic, he could not touch the oxygen mask at all.
"Hurry up, hurry up!" Xu Cang kept roaring in his heart. Although the plane's altitude was not particularly high, he could hardly breathe normally under the impact of the strong airflow. Without an oxygen mask, he would soon lose consciousness due to the low temperature.
Suddenly, his right hand, which was almost unable to feel the subtleties, suddenly touched a protrusion. In fact, Xu Cang didn't know whether it was an oxygen mask or not, but he didn't care anymore. He just pinched the protrusion and pulled it up hard. If he didn't pull the thing up, Xu Cang would almost be sentenced to death.
However, perhaps God had blessed him, and Xu Cang did not miss the last chance. With his strength, the entire oxygen mask was pulled out directly.
The oxygen masks installed in this 737 are not of the face-covering type, but only cover the mouth and nose.
The moment he saw the oxygen mask, Xu Cang cursed unnoticeably. He thought it would be great if it was a full-face oxygen mask, which could help him block the incoming rain and air currents to a certain extent.
However, Xu Cang could not care about these things at this time. As the oxygen mask was pulled open, the oxygen system in the cockpit began to work. Xu Cang kept pinching things, so that oxygen could be filled in the root canal that the mask was fixed on. Only by using gas to open the root canal, he could put on the oxygen mask more conveniently, otherwise, the difficulty of wearing it would increase exponentially.
As his right hand was already starting to lose control, Xu Cang gritted his teeth, moved his left hand to the grip of his right hand, and then made a circle back to balance it.
Such a weird grip was not what Xu Cang wanted, but the electric balancing switch was right on the grip of the right hand, and it was usually controlled with the right thumb. If it was controlled with the left hand, an awkward grip would have to be adopted.
He no longer had time to input an appropriate pitch trim to maintain a perfect state without human control. Therefore, Xu Cang just casually adjusted the stabilizer trim to ensure that the plane did not fall.
After the trim was applied, the aircraft just rose slightly, and then began to lower its head. This meant that the pitch trim value input by Xu Cang was not enough.
However, Xu Cang did not intend to care. When the plane briefly lifted its head, Xu Cang's left hand was freed for a moment. Almost at the last second, he grabbed the inflated root canal behind his head with his freed left hand, then pulled it down hard, then adjusted it with his right hand, and finally released his right hand, and the system stopped supplying air. Under the action of elastic force, the root canal of the oxygen mask instantly tightened, fixing the mask firmly on Xu Cang's mouth and nose.
hiss!
The cold oxygen flowed into Xu Cang's mouth and nose like a stream, refreshing his heart, as if at this moment, Xu Cang was alive again.
However, at this moment, the plane began to descend. Xu Cang grabbed the throttle lever with his left hand again, held the steering wheel with his right hand, stepped on the throttle, and with a slight push of his right hand, the plane turned from a slow descent to a climb.
If he wanted to make the initial approach from Runway 03, he would first have to turn back to Cangkou and join the approach procedure of Runway 03 from Cangkou. Compared with the extremely complex airspace of Runway 21, the airspace of Runway 03 was relatively simple, and he could completely descend according to the approach procedure, and even without the controller's command, Xu Cang could fly down according to the procedure alone!
However, flying back to Cangkou does not mean flying back immediately. Turning immediately below the program-restricted altitude will only cause the aircraft to immediately crash into the valley walls on both sides, so he needs to first reach a safe altitude of 5,700 meters before he can start turning around.
After increasing the thrust to climb thrust, Xu Cang let go of the thrust handle with his left hand and groped down for the VHF1 first very high frequency in the upper left corner of the central console.
When he came here, he adjusted the backup frequency to the Yulong Airport tower frequency. By feel, Xu Cang found the frequency switching button and switched the radio frequency from the Jianchuan tower to the Yulong Airport tower frequency.
With his head lowered, Xu Cang shouted with almost all his strength: "Blue Sky 9200, is the blind landing signal for Runway 03 available now?"
At this time, in the control tower of Yulong Airport, as it had started to rain and hail outside, Lu Jinghua and other two went up to the tower control room and were debating whether to evacuate with the airport staff.
However, they had received news that another plane would come and try to land. Therefore, after the tower controller had the idea of ​​evacuating early, Lu Jinghua took great pains to temporarily stabilize the tower controller and let him wait a little longer.
People were standing on the tower, looking far into the distance. The cloud mass on the five sides, like a pillar piercing the sky, was really oppressive and unimaginable.
Too close, too close indeed. Even with his naked eyes, Lu Jinghua could tell how close the weather was to the field. He then looked at the wind bags on the side of the runway. One was blown parallel to the ground, and the other, with its pole, had disappeared.
The controller at the Yulong Tower had an anxious look on his face. Looking at the approaching thunderclouds, he could not help but complain: "Under normal weather conditions, the airport would have been closed long ago. Why is this happening?"
Lu Jinghua was also extremely anxious at this time, constantly searching the sky for traces of the plane. He pointed at the radio communication equipment and said, "Is this thing okay?"
"Oh, it's available, it's available." The controller also scanned the sky with Lu Jinghua, but it was pitch black, and there was no plane to be seen. "I wonder if the people in your company are crazy. The weather is so bad, and there is no navigation for runway 21! If there is a flight accident, you will drag us down with you."
However, Lu Jinghua didn't want to talk nonsense with the controller at all. He scratched his head and was very annoyed. According to the time, the plane should be entering the vicinity of the airport airspace. Even if the handover was late, it should have switched to the Yulong Tower frequency at this time. Why was there still no movement?
In addition, due to the damage caused by the earthquake to the communication base station, Yulong Airport is located in a remote area, and the contact with Jianchuan is intermittent, making it inconvenient to obtain information about Blue Sky 9200 from Jianchuan.
If he was sure that Blue Sky 9200 had given up the approach, he would have evacuated with the airport staff. But if Blue Sky 9200 was still in the sky trying to approach, and he and the airport staff all evacuated, wouldn't the Blue Sky 9200 crew be left alone?
Suddenly, Lu Jinghua was in a dilemma. He was so angry that he cursed, "Your airport doesn't have the money to install air traffic control radar, but you can install ADS-B."
The controller was already annoyed, and upon hearing Lu Jinghua's complaint, he immediately scolded, "Even the Capital Airport doesn't have ADS-B installed yet, and you're asking us to install it, are you kidding me?"
ADS-B stands for Automatic Dependent Surveillance-Broadcast, a device that can provide four-dimensional information of aircraft to air traffic controllers in real time. Although it cannot completely replace air traffic control radar in terms of rules, it can give air traffic controllers great control over aircraft. Moreover, the equipment cost and maintenance cost of the ADS-B system are much lower than those of air traffic control radar, making it a highly cost-effective auxiliary control device.
If Yulong Airport has ADS-B equipment, once the Blue Sky 9200 enters the detection range, the tower will be able to see the real-time status of the aircraft just like the radar at a large airport.
Lu Jinghua was so anxious that he was confused. He scratched his head embarrassedly and was about to apologize, but a sharp noise suddenly came from the communication speaker, followed by a vague voice: "Blue Sky 9200, is the blind landing signal for Runway 03 available now?"
At first, Lu Jinghua and the controller hadn't reacted. In this kind of thunderstorm, the radio is often affected, resulting in the generation of background noise similar to the sound of electricity.
However, Wang Xuan, who had been silent, heard Xu Cang's voice. His face changed drastically: "Stop talking, someone is calling!"
"What?" The controller was startled. "It was someone calling just now, not background noise. Holy shit!"
He quickly picked up the phone and said, "Yulong Tower, who was calling just now?"
Amid the constant noise, a sporadic voice was heard again: "Yulong Tower, is the blind landing signal for Runway 03 available?!"
"Xu Cang!" Lu Jinghua recognized Xu Cang's voice, even though it was not clear. However, Lu Jinghua soon realized that something was wrong. Shouldn't he have landed on Runway 21? How could he have landed on Runway 03?
"Did I hear correctly?" Lu Jinghua pointed at the speaker: "He was talking about number 03, not number 21?"
To be honest, the tower controller was also a little confused about the situation. All the previous planes had also tried to land using No. 21. Wasn't this already a consensus?
"Blue Sky 9200!" the tower controller shouted, "You should use Runway 21. You can't stop on Runway 03!"
However, the answer he got was Xu Cang's increasingly weak voice: "Blue Sky 9200, now located between Cangkou and the starting turning point, ascending at an altitude of 5,400 meters, ascending to a safe altitude of 5,700 meters and returning to Cangkou, joining the approach procedure for Runway 03, circling and landing on Runway 21!"
By the end, Xu Cang's voice was already faint and almost drowned out by the noise.
However, this sentence shocked Lu Jinghua deeply. He muttered to himself in a daze: "Circling approach, he has to go from 03 to 21 to land, so he needs the blind landing signal navigation of runway 03! No, no, but Yulong Airport obviously does not have a circling approach procedure!"
Next to Lu Jinghua, Wang Xuan's face darkened completely: "He is crazy!"
The tower controller put his hands in his hair. For a moment, he was also confused. "I also remember that there was no circling approach procedure. What did he...what did he mean?"
Immediately, the tower controller held the microphone and yelled: "Blue Sky 9200, there is no visual circling procedure at this airport, there is no visual circling procedure at this airport, there is no visual circling procedure at this airport!"
He kept repeating, almost shouting until his throat broke. However, all he got in response was meaningless noise. The tower controller looked pale: "It's over!"
However, Lu Jinghua was talking to himself: "He said he was between Cangkoutai and the starting turning point, so... that should be that direction!"
After saying that, Lu Jinghua turned directly to the north of the fifth side, reached for the telescope on the table, and searched the sky there.
As long as the plane can reach a safe altitude of 5,700 meters, it means it is out of the valley and can be visually observed.
"Xu Cang, Xu Cang, Xu Cang! What on earth are you going to do!" Lu Jinghua kept muttering to himself. He didn't believe that Xu Cang was crazy, but there was clearly no visual circling approach at Yulong Airport. What was he thinking?
Just when Lu Jinghua was in a state of confusion, he suddenly discovered a tiny black dot between the gaps between the peaks. It was the Blue Sky 9200!
"Here it comes!" Lu Jinghua was so excited that he almost shouted out.
Guided by Lu Jinghua's voice, Wang Xuan and the tower controller also looked in the direction of Lu Jinghua's gaze. Fortunately, there was no obvious visual obstruction in this area, and they could vaguely see a black dot passing through the peaks with their naked eyes.
"There really is a plane!" The tower controller was startled: "No! He can't climb out!"
Almost at the moment when the tower controller's voice fell, the black spot that had just appeared disappeared again. It was not blocked by the mountain, but rushed into the thunderstorm cloud that looked like a giant beast like a moth to a flame.
Lu Jinghua's body tilted, his hands went limp, and the telescope fell down, the lens shattering with a crisp sound.
…
In the cockpit, Xu Cang kept trying to call the Yulong Tower to check whether the blind landing signal of Runway 03 was available. Because he had only considered Runway 21 before, and had not thought about the availability of Runway 03 at all, there was really no relevant information about Runway 03. When the blind landing signal of Runway 03 was really needed, it became awkward.
Since the visual circling approach needs to comply with strict restrictions on the protected area, each flight must be strictly calculated, including deviation corrections for wind direction, wind speed and flight altitude. Once there is a problem in any of these links, the aircraft will easily leave the protected area, and once it leaves the protected area, the aircraft will immediately face the risk of crashing into the mountain.
As the starting point of all procedures, the altitude of 2,300 feet on the localizer of runway 03 is the starting point, and this point must not be wrong. If this point is wrong, everything else will be wrong, and it cannot be corrected, so the blind landing signal of runway 03 must be available, otherwise everything will be over.
However, Xu Cang called Yulong Tower twice but received no response. As a result, Xu Cang could only use a blind transmission method on the frequency to inform the tower of his intention: "Blue Sky 9200, now between Cangkou and the starting turning point, ascend to an altitude of 5,400 meters, rise to a safe altitude of 5,700 meters and return to Cangkou, join the runway 03 approach procedure, circle and land on runway 21!"
He no longer cared whether the tower had received the signal or whether the blind landing navigation for Runway 03 was available. He would just fly there first.
After broadcasting his intention, Xu Cang's whole body began to twitch involuntarily, which he could not control. It was obvious that he had reached mild hypothermia, and his core temperature began to drop.
"Wait a little longer, hold on a little longer!" Xu Cang's heart kept beating, and he was thinking about the blood being pumped through his limbs in order to maintain his body temperature as much as possible.
But he has really reached his limit, and he is about to accomplish something astonishing within this limit.
But suddenly, Xu Cang seemed to sense something. He raised his head in the wind and rain, and in his eyes, which were barely open, he saw that the altimeter on the PFD, which was already covered with rain, was not moving!
"The altitude is not rising?" Xu Cang's breathing stopped at this moment. He pushed the lever again, and the throttle was almost at maximum, but the altitude was only rising at an extremely slow speed.
"No, no, no, no!" Xu Cang's mind went blank. He suddenly remembered that a thunderstorm cloud is an incredibly strong convection system in the development stage. The airflow inside it is constantly developing upward, which causes a large range of downward airflow in the surrounding area.
The thunderstorm clouds ahead were so strong that the surrounding downdrafts pressed the aircraft so hard that even at full thrust it could not lift its head.
"A rise rate of two hundred!?"
That's right, Xu Cang clearly saw that the altitude indicator only showed a climb rate of 200 feet per minute. However, at this moment, the plane was rushing towards the thunderstorm cloud at a speed of more than 200 knots.
"I can't climb out!" At this moment, Xu Cang looked at the still towering rock walls on both sides. He couldn't turn at all. However, the almost negligible ascent rate under the influence of the downdraft could not take him out of the valley at all!
The thunderstorm cloud that had occupied almost all of Xu Cang's vision was like a mountain pressing down on him, almost suffocating him, and the constantly exploding and flowing lightning in it made Xu Cang fall into despair and unable to extricate himself.
He couldn't fly anymore, so other than crashing into the mountain, he had no choice but to keep moving forward!
For some reason, at this moment, many images flashed through Xu Cang's mind, and then at a certain moment, everything stopped. As the clouds approached, rain poured into the cockpit as if it had pierced the sky.
Xu Cang's whole body was shaking. Suddenly, an arc of electricity split the sky, reflecting Xu Cang's pale face. His right hand tightly grasped the steering wheel, tighter than ever before.
His lips moved slightly, and amid the explosive thunder there was a very slight sigh: "God, please protect me one more time!"