The two completely different surging sounds were like heavy hammers constantly hitting Xu Cang's heart.
For a four-engine aircraft like the 747, the impact of an engine failure is not as great as that of a twin-engine aircraft. It is precisely because of this huge margin that four-engine aircraft do not need to comply with ETOPS standards.
However, if the second or third engine also stalls, the situation will be completely different.
"Is it surging again?" The captain in charge also heard the surging sound and his eyes drifted away from the N1 speed for a moment. Sure enough, the N1 speed of the No. 1 and No. 3 engines had begun to become unstable, which is also one of the signs of engine surging.
"Tell Jakarta control that we will conduct a single-engine descent." Xu Cang said immediately.
The second captain was startled, obviously puzzled by Xu Cang's descent: "Aren't you maintaining altitude? Won't the volcanic ash be thicker when you go down?"
"There are only three engines left now, and two of them are surging. We have to descend." After that, he needs to reduce the thrust of the No. 1 and No. 3 engines to at least ensure that they do not stall. In this environment, if they stall, they may not be able to restart.
As long as the No. 1 and No. 3 engines are operated at reduced thrust, most of the power demand will be placed on the No. 2 engine, which will obviously exceed the capacity of the No. 2 engine.
What's more, operating in a volcanic ash area, the high thrust and high speed can more easily cause damage to the engine. Xu Cang doesn't want the only engine that is still operating normally, the No. 2 engine, to have problems.
The captain thought about it and nodded heavily. Previously, if three engines were working properly, it didn't matter if one engine was scrapped. Now if they still hold on, there is a high possibility that only one engine will be left, and it is unknown whether this engine can hold on.
In the final analysis, it was because I was too reckless to cut off the No. 4 engine. If I could stay above 35,000 feet, I would be at the upper edge of the volcanic ash area, where the concentration of volcanic ash is not high. Then the remaining three engines that can still operate normally would not have problems so quickly.
Now engines one and three are also having problems. In fact, their condition is already quite critical so far.
"At what altitude should we descend?" the responsible pilot asked. Suddenly, the responsible pilot thought of something: "We can't even find a reliable airspeed operator right now, so how can we fly at the descending speed?"
After this reminder, the second captain also woke up. Yes, if the plane wants to land, it must follow the landing speed. But now they don't know what the airspeed of their plane is, how can they land?
Sure enough, the unreliable airspeed fault seems to have little impact, but in actual flight, this fault will cause many problems, and it will be impossible to complete a drift landing.
"Also, if we drift down, how can we be sure that the aircraft is within the limits?" The captain added, "There is no relevant chart for drifting down in the flight chart of unreliable airspeeds. We don't have any relevant data to refer to."
The responsible captain and the second captain both understood why Xu Cang wanted to make a floating landing. With the power now damaged, it was unknown whether the plane could make it to Jakarta's Soekarno-Hatta Airport.
Therefore, while the altitude is still sufficient, Xu Cang hopes to use floating descent, a method with the highest gliding ratio, to convert as much altitude as possible into horizontal displacement.
At this time, it actually involved a fatal problem, that is, whether the plane could still fly to Soekarno-Hatta Airport. Before that, the captain was still quite confident, after all, the failure of only one engine was not too serious for a 747, but the situation was different now.
Calculations for high aspect ratios must be taken into account in order to handle the most extreme cases.
However, the optimal solution now is naturally to let the aircraft drift down and travel a longer distance with the same altitude loss, but they cannot complete this operation at unreliable airspeed.
Due to the lack of real data reference, the most direct problem is that it is impossible to distinguish whether the aircraft is in an extremely dangerous situation, such as stalling or overspeeding. Because when the airspeed is unreliable, it is often accompanied by false overspeed and stall warnings.
However, logically, the crew cannot distinguish whether the overspeed and stall warnings are false. All they can do is to complete the climb, cruise, descent and approach according to the specific settings in the flight performance chapter, and the way to change the aircraft state is limited. As long as the aircraft state is changed in these limited ways, theoretically, the aircraft can be kept within a reasonable speed range, that is, the overspeed and stall in this state can be considered false.
However, the limited ability to change aircraft status can also cause many problems.
For example, you can only use maximum climb thrust , and you can only set EPR and N1 speed at a specific altitude and gross weight when cruising. It is this limited way of changing that conflicts with the idea of ​​drifting down, because there is no aircraft setting for drifting down in the unreliable chart.
If the crew follows their own instincts, how should they respond to any subsequent warnings in the aircraft data? Ignore them, or follow the standard recovery procedure?
How can the crew recover from overspeed or stall when the airspeed is not clearly known? So, this is a dead end.
"But we are lucky!" Under the watchful eyes of the captain in charge and the second captain, Xu Cang actually began to slowly reduce the throttle. He did not just reduce the throttle on the No. 1 and No. 3 engines that had problems, but also on the No. 2 engine which was still functioning normally.
Xu Cang said calmly: "The drifting speed of a 750,000-foot aircraft below 30,000 feet is actually about 285 knots, and the descent setting at unreliable airspeed is one degree of attitude, slow thrust, theoretically forming a speed of 290 knots, and a descent rate of 2,200 feet per minute. The drifting speed of 285 knots is basically consistent with the theoretical speed of 290 knots set at the slow setting at unreliable airspeed, so for a period of time, we can take both into account."
The captain was stunned when he heard this. He grabbed the checklist and quickly flipped through the unreliable airspeed and drift charts. He then took a deep breath and said, "It's really the same!"
The second captain waved his hand and asked the responsible captain to show him the checklist. As a result, after he looked at it, he felt that his three views on life were deviated. Originally, the airspeed was unreliable and the aircraft was drifting down, which were completely irrelevant and could not be achieved at the same time. However, Xu Cang could turn decay into magic and combine the two into one?
This move alone really shocked the second captain!
Exquisite, too exquisite in fact!
So, while Xu Cang was reducing the throttle, neither of the two captains dared to say anything. They were truly convinced.
"However, as the aircraft's altitude changes, the speed difference between the two will gradually increase. By then, we can just follow the unreliable airspeed flight chart. If we want to descend, we'll just do our best and leave the rest to fate." Xu Cang said, "Now we have to descend. If... if we're lucky, we'll break through the bottom layer of the volcanic ash mass at low altitude. Then, everything will be easy."
Volcanic ash clusters are actually similar to clouds. Their positions are neither too high nor too low. Perhaps as the aircraft's altitude decreases, the aircraft can directly descend below the volcanic ash cluster, where the concentration of volcanic ash will be much lower. Perhaps, if they can hold on to that altitude, they will have a way to survive by flying ultra-low altitude over the sea.
"I hope so!" When Xu Cang began to reduce the throttle, the captain in charge directly contacted Jakarta Control: "Jakarta Control, British Airways 1009!"
"British Airways 1009, Jakarta Control, go ahead!"
"Our No. 4 engine has stalled, and the No. 1 and No. 3 engines are surging. We can no longer maintain altitude and are now returning to Soekarno-Hatta Airport in a drifting mode!"
"British Airways 1009, there are no aircraft conflicts below your route now, you can descend on your own." Jakarta controller said immediately: "We have received a notice from Soekarno-Hatta Airport. They measured that the visibility and vertical visibility at this airport are both below the Category 1 standard."
"What about Category 2?" This question was not asked by the captain in charge, but by Xu Cang, and it was asked in English.
Xu Cang’s spoken English is not very good, but that doesn’t mean he can’t speak it at all. He has no problem with some simple communication.
"Can you fly a Category 2 flight even with an engine failure?" The captain in charge was stunned.
Xu Cang actually didn't want to fly like this, because in the second category of operation, the first choice in any country is the implementation of autonomous driving. If all countries can maintain consistency, it means that the implementation of autonomous driving is the optimal solution for the second category of operation. Manual flight, especially when the power is damaged, is not a suitable option.
But if there were better options, Xu Cang would not take such a risky choice. After all, he had just learned that the Sukarno-Hatta airport was also covered by volcanic ash. If there were other problems during the approach, it would be difficult to deal with.
"As long as there is a stable guidance signal." Xu Cang said calmly.
But God seemed unwilling to give Xu Cang and his team this risky option. The Jakarta controller said, "The airport is still studying it. The concentration of volcanic ash is increasing very quickly. It may be..."
Hearing this, the captain's face turned pale instantly: "Maybe it can't even meet the second-class standard?"
"That's right. Right now, our runway visibility is less than 400 meters, and our vertical visibility is between 100 and 200 feet. According to this standard, it meets the Category II standard. However, according to the weather report released 20 minutes ago, the runway visibility is still 3 kilometers, and the cloud base is 2,000 feet... At this rate of deterioration, we will soon not be able to meet the Category II standard."
Xu Cang couldn't help but tighten his grip on the steering wheel. In less than twenty minutes, the weather standards at this airport had dropped so much. By the time they arrived at Soekarno-Hatta Airport, it would be impossible for them to still meet Category II standards.
"What about Singapore Changi Airport?" the airport responsible asked immediately.
The only airports in the vicinity that can land are Soekarno-Hatta Airport and Singapore's Changi Airport. This is when the 747's disadvantage in choosing alternate airports is revealed. Due to its large size and extremely long take-off and landing distance, smaller airports simply cannot meet the landing standards. Only large airports can land, so the range of options they can choose is actually very small.
Singapore's Changi International Airport is a world-renowned large hub with three runways, which is larger than Soekarno-Hatta Airport and is a pretty good additional option.
However, Changi International Airport is still west of Soekarno-Hatta Airport, which increases the flight time and is not very friendly to today's power-impaired aircraft.
However, compared with Soekarno-Hatta Airport, which cannot even meet Category II meteorological standards, Singapore Changi International Airport is probably relatively better.
However, just as this thought came to mind, the regional control department dealt a fatal blow: "From what I have learned, Changi International Airport has stopped taking off and landing, and it is very likely that the airport will be closed soon. In fact, Soekarno-Hatta Airport also plans to close the airport, but because it previously agreed to accept your alternate landing, it has not yet officially announced it."
In fact, it is quite clear at this point. Mount Kelud is a giant active volcano. Once it erupts, the impact range is unimaginable. It should be said that even Changi International Airport and Soekarno-Hatta Airport can't withstand it now. Even if Xu Cang and his men want to take a risk and land at some smaller airports, it is impossible.
It seems that in this big world, there is no place for them to stay?
In this situation, even if there were two pilots on the plane, the atmosphere dropped to freezing point in an instant. The most important thing was that it was still in the development stage of volcanic ash. Not to mention whether they could hover and wait, even if they found a way later, such as hovering over the sea at low altitude, they would definitely not be able to wait until the volcanic ash dissipated.
On the eve of running out of fuel, the volcanic ash situation will only get worse!
Xu Cang did not let the captain respond. He probably understood what the controller was saying, and could clearly sense the almost desperate atmosphere in the cockpit. But Xu Cang did not give up. He had experienced even more desperate and depressed moments, so how could he give up so easily?
"What about the three types of blind landing?" Xu Cang suddenly said.
When these words were spoken, not only the two pilots next to them, but even the controller on the radio channel were shocked.
Xu Cang didn't care about these people's reactions: "Can Sukarno-Hatta Airport provide Category III ILS operations? According to the current development trend, Category A and Category B are unlikely to meet the standards. Only Category C among the three can meet the standards unconditionally. Does Sukarno-Hatta Airport have this capability?"
"Xu Cang, do you have the qualifications for Category III ILS?" The captain looked at Xu Cang in disbelief: "I remember that you CAAC basically don't operate Category III ILS, right?"
As we all know, there are three standards for blind landing, namely Category I, Category II and Category III. Category I is the most common. Generally speaking, the standard for Category I blind landing is that the runway visual range is not less than 550 meters and the decision height is not less than 60 meters. This is the standard for most blind landing systems today.
Once the meteorological standards do not meet the standards for Category I ILS, if the airport has Category II equipment capabilities and permission from the authority, it can further operate Category II ILS standards, that is, the runway visibility is not less than 350 meters and the decision height is not less than 30 meters. The meteorological standards requirements are much lower than those for Category I.
However, Category II operations not only have requirements for airports, but also have special requirements for aircraft and crew qualifications. It is for this reason that there are actually not many Category II operations.
However, there is also a Category III standard ILS above Category II. Category III ILS, like Category II ILS, requires various authorizations and qualifications, so even if you look at the world, there are only a handful of airports that can operate Category III ILS and crews that can perform Category III ILS.
Importantly, the three categories of standard blind landing are divided into three subcategories, namely A, B and C. The standard of category A is the most extensive, that is, the runway visual range is not less than 200 meters, and the decision height is not less than 30 meters. The runway visual range of category B is 50 meters, and the decision height is usually 15 meters. However, in theory, even if the decision height requirement of 15 meters is not met, it is acceptable, that is, under the premise of meeting the runway visual range, the vertical visibility of zero also meets the standards of category B blind landing.
The Category 3C blind landing mentioned by Xu Cang is truly "pitch-dark", with no requirements for runway visibility and vertical visibility. In other words, Category 3C blind landing operations can be carried out even under extreme conditions where the runway visibility and vertical visibility are both zero.
Category 3C blind landing is the highest level of instrument landing standard that truly transcends all visibility standards.
However, even the relatively relaxed Category IIIA standard is basically not implemented by CAAC. That’s right, even if the airport can operate and the weather conditions are met, the airport will not choose to operate Category III ILS.
The captain in charge had flown in China for several years. As far as he could remember, it seemed that only certain runways at two or three airports had Category III ILS, and as far as he knew, he had never heard of such operations.
It is based on this known information that the responsible captain asked this question. In fact, British Airways is also an internationally renowned airline, and there are very few crew members in British Airways who have Category III blind landing qualifications.
"No!" Xu Cang's answer was so decisive and seemed so natural that the captain in charge even doubted whether Category III blind landing required crew qualifications.
"I have three types of qualifications!" At this moment, the second captain suddenly spoke, and his words really shocked everyone. Even Xu Cang couldn't help but look at him.
That's Category III ILS. Even after 20 years, there are only a handful of airports in China that can operate Category III ILS. The main reason is that Category III ILS requires too high accuracy and stability of guidance signals, and many airports cannot maintain such a sophisticated instrument landing system.
The responsible captain interrupted at this time: "But all three types of qualifications must be possessed by everyone present. It is useless if only one person has them."
"That's not what I'm talking about." The second captain said seriously, "In fact, Category C blind landing has not been approved by ICAO. In other words, it's just a concept, not a technology that can be applied in actual operations."
"What did you say?" The responsible captain did not have the same theoretical knowledge as the second captain because he had not participated in the qualification acquisition of Category III ILS. He knew the three subcategories of Category III ILS, but he did not expect that Category C was not approved by ICAO.
Perhaps a "true" blind landing without runway visual range and vertical visibility requirements is beyond ICAO's understanding of landing safety, even if it is technically possible.
"It doesn't matter whether it is approved or not, as long as Sukarno-Hatta Airport has the ability to implement Category III blind landing. Not allowed and not able to fly are not the same thing." Xu Cang said indifferently, as if he had already known that Category IIIC blind landing was not allowed.
The second captain's face suddenly changed: "You mean, if Sukarno-Hatta Airport can carry out Category C blind landing, you will violate the rules?"
"That's right!" Xu Cang answered the question directly, clearly and without any doubt: "In fact, even if they don't have a Category 3C blind landing signal, even a Category 3A blind landing signal is enough to guide the plane correctly to the runway!"
"You are violating the rules!" the second captain shouted.
Not only was the crew unqualified, it was also unclear whether the aircraft's current condition allowed for a Category III blind landing. Moreover, Xu Cang actually wanted to use the Category IIIA blind landing signal level to replace the Category IIIC blind landing signal, which was obviously wrong.
"If there is a method that does not violate the rules and can allow me to land safely, you can give it to me." Xu Cang said coldly.
Just as the two were arguing, the voice of Jakarta control came over the radio: "British Airways 1009, we have received feedback from Soekarno-Hatta Airport that this airport has Category III blind landing equipment."
As soon as these words came out, Xu Cang's body tensed up involuntarily. Finally, God did not close all the paths for him.
The second captain, who had just been arguing about implementing Category III blind landing under such conditions, did not raise any objections, as if he had acquiesced.
"Help us contact Soekarno-Hatta Airport and ask them to activate the Category III blind landing signal. We still plan to return to this airport." Xu Cang made the decision directly and made it final.
Xu Cang's plan now was to quickly descend to a low-altitude environment at slow engine thrust. At slow engine thrust, the damage to the engine from volcanic ash could be minimized. As long as the concentration of volcanic ash was reduced at low altitude, they might be able to fly normally. Then, they would maintain a low-altitude flyover to Soekarno-Hatta Airport and conduct a Category III blind landing.
It is true that Category III blind landing requires automatic driving, but Xu Cang is confident that as long as the plane does not encounter any major problems, he can maintain the navigation accuracy of the plane at the automatic driving level under manual control.
This is the reason why Xu Cang has the confidence to ignore the rules. As long as he is given a guiding signal, he can land on the runway.
However, Xu Cang had already planned the follow-up flight plan, but the control gave them a piece of news that made them feel desperate: "British Airways 1009, Soekarno-Hatta Airport can indeed operate Category III blind landing, but not long ago, the airport's self-inspection found that the blind landing equipment was damaged by volcanic ash and is still under repair."
These words caused the three people in the cockpit to fall into a long silence. Now, not only the signals of Category III blind landing, but also Category I blind landing were gone.
"How long do you expect it to be repaired?" asked the captain in charge.
The regional controller said: "We don't have a definite news yet, but it is expected to be more than six hours."
"Six hours..." Xu Cang felt as if his heart was being squeezed tightly, and he almost couldn't breathe. Six hours, they didn't know if they could last even an hour in this environment.
"Let's maintain the course first!" The captain in charge had no idea at the moment. He could only apply to maintain the course and fly towards Sukarno-Hatta Airport, and then make a decision later.
"Okay! British Airways 1009, please contact us if you need anything."
The radio stopped and the cockpit fell into a long silence. Finally, the second captain broke the silence: "The air clearance around Sukarno-Hatta Airport is very poor. We cannot approach without the help of the instrument landing system."
"What should we do then?" The captain in charge asked this soul-searching question. There were only two airports where they could land. The blind landing at Soekarno-Hatta Airport was not available, and Changi International Airport was directly closed.
"What about non-precision approaches?" Xu Cang asked, "Does Sukarno-Hatta Airport have non-precision approaches?"
"There is a VOR/DME approach to Runway 27," the captain said, "but the minimum descent altitude there is 500 feet above the ground, and we can't get down to the last 500 feet."
The meteorological standards for non-precision precision approaches are much higher than those for precision approaches. The decision height for Category I blind landing alone is only two hundred feet, while the minimum descent altitude for VOR/DME approaches is more than doubled.
In the logic of the responsible captain, a Category 1 blind landing does not even meet the standards, let alone a non-precision approach.
However, Xu Cang did not pin his hopes on non-precision approaches. He just asked, "Is there an angle between the VOR/DME approach course and the extended line of the runway?"
Generally speaking, the final course of a VOR/DME approach coincides with the extended runway line, but due to certain external reasons, the final course may have a small angle with the extended runway line.
In fact, in some extreme cases, the localizer of blind landing can be at an angle with the extended line of the runway, not to mention non-precision approach.
"That's not the case. The VOR final course of Runway 27 is aligned with the runway extension line, both are 271 degrees." The captain in charge said this, and suddenly felt something strange: "Xu Cang, what do you want to do? The final clearance conditions at Sukarno-Hatta Airport are very poor, and you must not land blindly. Sometimes, even under blind landing guidance, if the descent rate is not well controlled, the terrain warning will sound."
After the captain finished speaking, the cockpit fell into a strange silence. To be honest, the current situation is quite clear. Their choices are very limited. One is Soekarno-Hatta Airport, and the other is Changi International Airport. One can land but cannot, and the other is simply closed.
"To be honest, even if Changi Airport hadn't been closed, we probably wouldn't be able to fly there." The captain lowered his head and said absentmindedly, "There's a volcano called Serume between Soekarno-Hatta Airport and Changi International Airport. It seems like we can't get over it now."
If the planes continued to fly in the volcanic ash, they would most likely not be able to fly to Soekarno-Hatta Airport. The only thing they could hope for was that the concentration of volcanic ash would decrease at low altitudes.
However, the altitude of Serume volcano is nearly 4,000 meters. To fly over this mountain, the plane must reach an altitude of more than 14,000 feet to be relatively safe. At this altitude, the plane will inevitably enter the volcanic ash again, and this altitude is likely to be the range with the highest volcanic ash concentration.
If they tried to force their way over Mount Serumeli, there was a high possibility that they would lose power in the volcanic ash and crash into the mountainous area before they could even get over it.
"Xu Cang..." The captain in charge suddenly said, "I heard that you completed an emergency landing at sea not long ago!"
"What, forced landing at sea?" The second captain almost jumped up. "You have flown a forced landing at sea? How is it possible that you are so young and you can complete a forced landing at sea, and... succeed?"
Emergency landing at sea is a universally recognized difficulty in flying. There are too many variables, but this young man in his twenties can actually complete an emergency landing at sea?
You know, in foreign countries, Xu Cang at this age can only be called a Baby Pilot, but even this baby pilot has had such a legendary experience.
However, the responsible captain ignored the reaction of the second captain and said seriously: "In the area we can fly to, there are only two airports that can accommodate 747 landings. Now that those two airports cannot land, then we will not land on land, but land in the sea!?"
The second captain was shocked by the captain's words, even more shocked than when Xu Cang had just completed an emergency landing at sea: "You mean, an emergency landing in the Pacific Ocean?"
"Xu Cang, you have had successful experience!" The responsible captain was really courageous: "I don't want to pin my hopes on something illusory, but I am willing to believe in you."
Xu Cang was stunned. He didn't say anything, didn't refuse, and didn't agree. In fact , Xu Cang had thought about this possibility before the responsible captain made this suggestion.
The land restricted them too much, but the vast Pacific Ocean offered a lot of opportunities. However, it was late at night, and unlike the previous emergency landing near the coast of Qizhou, the rising sun gave Xu Cang one last chance to make corrections at the last moment, otherwise he would have fallen into the water in the opposite direction.
However, the current time was totally wrong. There were still at least eight hours until sunrise. Did they have to wait in the sky for another eight hours? Moreover, there was another important question.
Last time in Qizhou, he could accurately control the location of the plane's emergency landing in the offshore area, which was very convenient for sea rescue. However, this time, Xu Cang was unable to choose a suitable area for the emergency landing due to his ignorance of the surrounding terrain.
Yes, the Pacific Ocean is huge, but if they land a little further away, in the middle of the night in the open sea, even if they manage to land, will they be able to survive until rescue arrives?
Just as Xu Cang was hesitating, there was a click and a black ink spot fell on the windshield.
The voice was so dull that it seemed to touch Xu Cang's nerves. He looked over there and saw more and more ink dots appearing on the windshield. All of a sudden, these ink dots merged into a line and flowed down along the windshield.
"It's raining?" Xu Cang frowned. It was clearly rain mixed with volcanic ash dripping onto the fuselage.
The rain would not have a big impact on the aircraft, but suddenly, the aircraft's main warning light lit up, and the display showed that there was a failure in the air supply system.
Xu Cang and the captain in charge looked up at the same time and saw that the light of component No. 1 was lit.
"The component is lit?" Xu Cang was a little annoyed. When people are unlucky, misfortunes never come alone. However, fortunately, the 747 has three sets of components, and the failure of one component alone will not have much impact.
"Shall I do a checklist?" asked the captain in charge.
Xu Cang nodded: "You do it!"
"Okay!" The captain in charge did not even open the checklist, but started directly. This was certainly not a legal move, but at this time, even the more rigid second captain did not raise any questions, because he was thinking about the possibility of an emergency landing in the Pacific Ocean raised by the captain in charge just now.
However, there seems to be no room for thinking now, and they don't seem to have any other choice.
The pilot in charge was quite familiar with the component checklist, which he practiced often during training. After confirming that the air adjustment switch was on, the pilot in charge turned the control selector of component No. 1 to position A and then pressed the component reset switch.
Soon, the component's fault information became blank, which eliminated the fault. It seemed to be just a minor problem.
Xu Cang did not look closely at the captain's actions. He only saw that the fault light was off and did not look at it again. Suddenly, Xu Cang saw a little liquid seeping out from the lower right corner of the windshield.
He was stunned for a moment, stretched out his hand and touched the lower right corner of the windshield with his finger, and immediately felt a slight dampness on his fingertips.
The captain in charge also noticed Xu Cang's actions and came closer: "What's wrong? Huh? Why is there water in the inner layer? Is it condensed from fog? No! It seeped in from outside?"
"The rain has seeped into the inner layer through the cracks in the outer windshield, but why is the inner glass so poorly sealed?" Just as Xu Cang finished speaking, the main warning light came on again. A look at the prompt showed that it was still a failure in the air supply system.
Perhaps because of his previous experience, Xu Cang first looked at the component light. Sure enough, the component light No. 1 that had just been reset lit up again.
"Turn the control selector to B!" Xu Cang said directly.
The captain in charge nodded, and without saying a word, he turned the control selector of component No. 1 to B and pressed the reset switch.
However, this time the fault information of component No. 1 was not eliminated. At the same time, not long after, the fault lights of components No. 2 and No. 3 also lit up.
"This!" The captain in charge was shocked and immediately looked at the pressurization panel and found that there was no problem with the aircraft's pressurization for the time being. However, if all three components were left in a faulty state, it was foreseeable that the aircraft's pressurization would have problems.
"How come all three components are broken?" It was the first time that the second captain had seen such a situation.
He had seen one or two components fail, but how could all three fail? The probability was too small.
If the probability of something happening is so small that it is almost impossible, then we should consider that it is not a matter of probability, but some other problem that causes the failure to inevitably occur.
"Could it be the air bleed problem?" Xu Cang thought for a moment and pointed at the wing anti-icing switch: "Turn it off and see!"
"Huh?" The captain in charge did not understand the motive of Xu Cang's behavior at first, but he was the captain after all, and he quickly remembered the reason.
The bleed air of the components depends on the engine. In a high altitude environment, the air content is already low. At this moment, Xu Cang has set all the engines to slow thrust. In this case, the amount of bleed air that the air source system can get through the engine is not much. Moreover, the wing anti-icing will consume a lot of bleed air, so the bleed air that can be allocated to the three components is very little.
In this way, with very little bleed air available, the component has to bear its own pressurization function, which is a bit like asking the component to eat grass and milk. The burden on the component will increase in a short period of time, and eventually it will jump away due to the heavy load.
After figuring out this section, the responsible captain immediately turned off the wing anti-ice switch. However, after waiting for a few seconds and resetting all components, the lights on all three components went out soon.
"Sure enough, there is not enough air!" The captain in charge breathed a sigh of relief. If there was a problem with the pressurization system, it would take a lot of effort. "Xu Cang, it's a good thing you reacted quickly!"
Really, by now the captain in charge is already exhausted.
Volcanic ash has caused too many chain problems. The presence of volcanic ash is likely to block the pitot tube, resulting in unreliable airspeed. At the same time, the static electricity accumulation caused by friction with the fuselage affects the aircraft's electronic systems, such as the flight management computer. Among them, the unreliable airspeed has the most extended problems. It is precisely because of the unreliable airspeed that the wing anti-ice switch needs to be turned on. At the same time, the throttle needs to be held down to slow thrust during descent. The two-phase influence leads to insufficient bleed air, which ultimately causes problems with the components.
The outer layer of the right front windshield cracked due to impact with a large piece of volcanic rock. As for the sealing problem of the inner windshield, the captain in charge did not know whether it was also related to volcanic ash.
It is precisely because of these problems and failures that all pilots are so afraid of entering volcanic ash.
However, no matter what, the component problem was finally solved. The captain in charge just felt relieved and wanted to talk about the possibility of an emergency landing at sea. The plane suddenly began to vibrate at a very high frequency without any warning, and even the steering wheel held by Xu Cang was vibrating left and right.
The discussion about the emergency landing at sea was quickly interrupted by this sudden situation. The vibration of the steering wheel was so violent that Xu Cang could hardly hold it. Moreover, the vibration of the steering wheel was only one aspect, and the plane seemed to be vibrating violently.
"Stick shaker?" The pilot in charge was stunned: "No! This is not the way to shake the stick in a stall!"
The first thing that the pilots think of when they hear cockpit vibration is the stall stick shaker, which is almost engraved in the pilots' genes. However, every time they prepare the cockpit, the pilots have to test the stall stick shaker. The pilots know very well what kind of warning the aircraft stick shaker is and what it feels like.
The control wheel was indeed vibrating, but it was somewhat different from the stall stick shaker. Moreover, Xu Cang was setting up the aircraft according to the chart in the flight performance, so it was impossible for a stall to occur.
However, compared to the vibration of the steering wheel, Xu Cang suddenly felt that there seemed to be something wrong with the plane's descent rate. Because according to the flight chart, at the current attitude and slow thrust, the plane's descent rate should be just over 2,000 feet per minute, but now it is getting faster and faster, almost reaching 3,000 feet per minute, which is a big gap.
"The descent rate seems to be wrong!" The second pilot also discovered this problem.
Xu Cang hesitated for a moment, and gently lifted the club with his right hand. However, he suddenly felt that the force of the club was incredibly light.
"How could this happen? Why is the pitch rod force so light?" Xu Cang was stunned, totally unable to understand why this happened.
"What did you say?" The captain in charge also used his left hand to pull the stick down, and he pulled out a long section quite easily. However, the reflection on the plane was that the plane's descent rate increased instead of decreasing, and it actually broke through the 3,000 feet per minute mark in an instant.
Such an abnormal phenomenon directly stunned the responsible captain and the second captain. How can you accelerate the descent of an aircraft with a stick? This is totally against common sense!
However, Xu Cang's reaction was so fast that he shouted, "Oh no, it's turbulence!"
Then, Xu Cang stopped pulling the stick and pushed the control wheel forward suddenly. In an instant, the aircraft's attitude was reduced to minus one degree.
"What are you doing!" the second captain shouted immediately.
Xu Cang's action of pushing the stick directly caused the aircraft's descent rate to exceed 4,000 feet per minute, and the aircraft was diving down at an unimaginable speed.
"The plane is stalled!" Xu Cang shouted, "The plane has entered a deep stall!"
"Deep stall, how is that possible?" The captain in charge did not react. However, if it was a deep stall, it would explain everything. In a deep stall, the control surfaces of the aircraft were full of turbulence, and the control surface effect was almost zero. It was for this reason that when Xu Cang was pitching the aircraft, he felt that the stick force was particularly small.
Because at this moment on the elevator, the airflow has been separated from the control surface, the reaction on the stick force is naturally quite small.
The actions of the responsible captain and Xu Cang in holding the stick undoubtedly increased the angle of attack of the aircraft. The underlying logic of stalling is that the aircraft's angle of attack is greater than the critical angle of attack, so the procedure for resetting the aircraft is to reduce the angle of attack. In this way, increasing the angle of attack will aggravate the stall condition of the aircraft, and the aircraft will naturally accelerate its fall.
However, the problem is that the plane was fine just a moment ago, so how could it suddenly go from a normal state to a deep stall? This change was too fast?
Suddenly, the captain in charge realized the only previous change, which was to turn off the wing anti-ice switch.
"Frozen...frozen?" the captain in charge murmured.
"Freezing rain, that's freezing rain outside. It will freeze once it touches the fuselage!" Xu Cang shouted, "Engines and wings anti-ice are all turned on!"
"What about the pressurization?" The second captain shouted, "Once the wing anti-icing is turned on, the pressurization will be gone! At this altitude, without pressurization, we can't survive!"
At this moment, the air outside was filled with volcanic ash and cold water vapor. Without components for pressurization and air circulation, there would be a large number of casualties in the cabin. How could the second captain accept this?
In his opinion, the aircraft's angle of attack is already very small and should be able to be modified.
However, at this moment, Xu Cang suddenly felt that the force of the steering wheel's push rod had become extremely small. He pushed the steering wheel directly to the end with almost no effort, but the aircraft's attitude did not change.
"The elevator rudder effect has completely disappeared!?" Xu Cang's face turned pale: "Stalled, can't correct it!"