Chapter 161 Let Our Planes No Longer Fear Frost and Snow (Two-in-One)

Half a month later.

Nanzheng, at the No. 182 Liulin Airport under the clear sky.

Two propeller planes, one large and one small, were parked at the end of the takeoff runway, waiting for weather conditions that met the test requirements to arrive.

They are naturally the Y-8F that has been modified and the MA-60 prototype that transferred from Haojing a week ago.

On their wings and tails, red, black and yellow ice thickness scales have been drawn——

In the case of insufficient accuracy of ice accumulation detectors, data can currently only be obtained through video and high-speed camera capture.

Under the leadership of Chang Haonan and Lin Guofan, Factory 182 and the School of Atmospheric Science of Jincheng University have achieved amazing work efficiency.

The former took only more than ten days to move the key area deicing system calculated by Chang Haonan from drawings to reality, while the latter has established special meteorological monitoring and control stations in Jincheng, Qinling and northern Xinjiang regions - based on the past Based on decades of experience, the above places are statistically the places with the highest ice accumulation frequency in the entire China.

However, after everyone waited for a few days, the weather was cloudless and beautiful throughout the northwest.

Under normal circumstances, this is the most suitable climatic condition for flying, but the natural icing test flight is to "face the difficulties" and create difficulties even if there are no difficulties. The current environment seems a bit embarrassing.

"Everyone, check the functionality of all anti-icing systems on the aircraft again!"

Liang Shaoxiu held a big loudspeaker in his hand and shouted to the staff on the other side of the plane.

"Mr. Liang, we have checked it three times today, especially the hot gas de-icing system. Frequent starting of the engine will also affect the life..."

The deputy next to him warned in a low voice with black lines all over his forehead.

Before conducting real natural icing tests, in accordance with the certification standards established by Chang Haonan, Lin Guofan and others, the aircraft first needs to verify the function, safety and performance characteristics of each anti-icing system in dry air.

But since it’s been sunny lately, this process has been done too many times.

"It's okay, I guarantee it's perfect. Just check it a few times and you'll be right."

In fact, Liang Shaoxiu himself knew that doing this would not have any practical effect, but if everyone was kept idle, it would lead to anxiety or laziness. It was better to find something to do and exercise instead.

"Chang Gong, in fact, based on our previous experience in icing test flights in North America, it is difficult to accurately analyze the characteristics of clouds in the airspace above 1,000 meters by relying on ground weather stations alone. It is best to have a weather detection aircraft to search for Suitable airspace for testing.”

An engineer seconded from Institute 602 said next to Chang Haonan.

The latter rolled his eyes:

"The truth is this, but if you want to modify a weather detection aircraft, you need to pass the natural icing test first, and if you want to pass the natural icing test, you need a weather detection aircraft..."

The engineer scratched his head and said nothing more.

"Everything is difficult at the beginning..."

Chang Haonan changed his posture, put his hands in his sleeves, looked up at the sky at an angle of 45° and sighed.

At this time, a piece of English with a strong Italian accent came from the side:

"My friends, are you really kidding me when you conduct natural freezing experiments in a place that is 1,500 kilometers away from the coastline and has no large water system?"

The speaker was a tall, thin Italian named Rossi Colombo, the head of the delegation sent by AgustaWestland to follow up on the airworthiness certification.

It's not surprising that he thinks so. The natural environment in southern Shaanxi and northwest China is indeed slightly different from the Great Lakes region in North America.

Seeing that someone was questioning his professional abilities, Lin Guofan, who was originally a soft-spoken person, immediately became furious:

"Of course, according to my research over the past ten years, from November to December every year, the frequency of ice accumulation in the airspace of the Qinling Mountains and northern Xinjiang is above 50%. Mr. Colombo, you must learn to be patient, be patient!"

Obviously, everyone was very anxious because they were unable to conduct experiments for many days in a row.

Seeing the two people who had become somewhat angry, Chang Haonan quickly reconciled in the middle:

"Professor Lin, don't be anxious. Everything will be clear when we find the freezing weather. Mr. Colombo is not a stubborn person. Look, he has already changed his clothes."

This sentence is said in English, so Colombo next to him can also understand it——

When he arrived in Nanzheng a few days ago, this guy wore a serious velvet suit and insisted that it was part of his professional image.

But within two days he was wearing a cotton-padded jacket with the aviation industry logo on it.

Now he is very skillful in imitating Chang Haonan and others in putting their hands together to keep warm.

Colombo looked down at the cotton clothes, pants and shoes he was wearing, opened his mouth and did not continue to say anything.

As the bickering between several people came to an end, the atmosphere around the runway became dull and boring again.

At this moment, a rustling sound suddenly came from the walkie-talkie placed on a table next to it, which immediately attracted the attention of almost everyone.

The signal transmission stability of this old-fashioned analog walkie-talkie is very poor. After being connected, you have to wait for a while before you can hear clearly what is being said on the other side.

"...The Qinling Weather Station reported that it was found that icing clouds that may meet the conditions are forming at an altitude of 1200-1500m. The airspace range consists of the following five coordinate points: 106.108E, 32.473N, 105.906E, 32.459N..."

Lin Guofan grabbed the pen and paper on the table next to him, wrote down the most important data on it, and then quickly gave his judgment:

"The designated airspace range is about 12,000 square kilometers, but judging from the speed of cloud formation, the time window left for us is not very long, and it may only be enough for one test flight."

The best meteorological conditions for natural icing tests are "snowy". Therefore, if the clouds are too thick or the temperature is too low and it starts to snow, there will be no test flight conditions.

Everyone looked at each other, and finally turned their attention to Chang Haonan:

"Comrade Xiao Chang, you decide, should the Yun 8 go up first or the Xinzhou 60 go up first?"

"Since the airspace is large enough and the time is short, there is no need to prioritize. I think it is better to let the two aircraft fly together. This way, the possibility of successfully collecting data is greater."

The responsible comrade from the 603 Institute and Liang Shaoxiu from the 182 Factory looked at each other, and then nodded at the same time:

"Okay, let's take a test flight together!"

Lin Guofan next to him also raised his head at this time:

"I have heard from comrades who have been to the United States before that they will have random meteorological engineers there to make specific decisions based on the actual situation after the plane arrives in the predetermined airspace?"

The engineer from Institute 602 was stunned for a moment, then nodded:

"Yes, the flexibility and judgment accuracy of the ground monitoring mode are not enough. It would be much more efficient for meteorological engineers to follow the aircraft."

Having said this, he hesitated again:

"But to be honest, the FAA made this configuration based on their in-depth understanding of the meteorological conditions in the Great Lakes region and more than ten years of experience. Our natural icing test has just begun. In terms of safety..."

Lin Guofan waved his hand and directly interrupted the other party's worries:

"Yu Li, the FAA has been tracking the meteorological conditions in the Great Lakes region for more than ten years. I have also been tracking the meteorological conditions in the Qinling Mountains for more than ten years. If Americans can do the same thing, can't I do it? Because Our natural icing experiments have just begun, and we need to take some risks to speed up the progress of the experiments."

"Yu Qing, I have participated in the whole process of the de-icing system design of the Y-8 aircraft. Going to the sky with me can also give more confidence to the crew members participating in the test flight. Comrades Xiao Chang and Xiao Liang are engaged in aircraft design. Zhu Lan They are engaged in surface physics. Instead of letting them increase the risk in vain, it is better to let me go up and be of some use."

"I have made up my mind on this matter and there is no need to mention it again."

At this time, Colombo, who was confused, understood what happened through a translator.

After a brief moment of shock and the embarrassment of being slapped in the face, he quickly rushed over with strode:

"I want to get on the plane too!"

"you?"

Chang Haonan and Liang Shaoxiu both turned their heads and looked at Colombo.

Although as a partner, the latter, representing AgustaWestland, could get permission to take off with the aircraft, the natural icing test is after all one of the only three Category I risk subjects. One less person to go to the sky means one less risk.

"Don't worry, I've done natural icing tests with the A109 helicopter, I'm experienced!"

Colombo patted his chest and promised:

"Furthermore, according to the contract, I must follow all test flight projects in order to receive the full bonus given to me by the headquarters."

…

After confirming the crew members on each aircraft, the two aircraft that had already completed their pre-flight preparations took off one after another under the command of the tower.

The Qinling area is not far from Nanzheng, so not long after Chang Haonan and others returned to the tower, they received a report that two aircraft had entered the test flight airspace:

"It was found that there were large-scale stratus clouds in the airspace, and the weather conditions above the stratus clouds were fine, which met the basic conditions for the icing test flight."

The tower commander began to issue instructions one by one according to the requirements of the test flight manual in front of him:

"Check that the test equipment is working."

The clear voice of the pilot soon came from the radio:

"Report No. 01, all test equipment is working normally."

"Report No. 02, all test equipment is working normally."

"Turn on the atmospheric parameter detector."

"Checking atmospheric parameters"

"..."

This time the interval between receiving responses is slightly longer:

"The cloud top height is 1800, the atmospheric liquid water content is 0.7g/m, and the average diameter of supercooled droplets is 35 microns, which meets the requirements of the continuous maximum icing test. Request to start vertical cloud detection."

"Requesting approval."

Due to the lack of satellite communication means, after the plane enters the water vapor-rich clouds, the quality of the call between the crew and the tower will drop sharply. Chang Haonan and the others can only hear a squeaking noise.

Vertical detection of clouds requires the aircraft to enter the cloud from above, descend to the bottom of the cloud, and then climb out of the cloud. It records the changes in liquid water content in the cloud during the change of vertical altitude and determines which altitude is most suitable for conducting the test. The entire process only lasts approximately It takes about 2 minutes, and the anti-icing system will be turned on throughout the entire process, which theoretically will not affect flight safety.

Still, not being able to stay in real-time contact with the plane was a bit nerve-wracking.

Finally, the noise on the radio disappeared.

Lin Guofan's voice reached everyone's ears:

"The cloud base height is 1200, the liquid water content in the atmosphere is 4.5g/m, and the average diameter of supercooled droplets is 105 microns."

"I plan to conduct natural icing test flights at 1500 and 1200 altitudes, each lasting 15 minutes, corresponding to Category 4 and 3 anti-icing capabilities in the airworthiness certification standards."

Obviously, he wanted to take advantage of the rare weather conditions in these months to complete all the test flight items specified in the manual at once.

According to the interim standards formulated by Chang Haonan and Lin Guofan, the anti-icing capabilities of aircraft are divided into four categories.

Among them, categories 1 and 2 correspond to imperfect anti-icing capabilities, and flights are only allowed when the weather is fine and there is no risk of ice accretion or a weak risk of ice accretion.

Category 3 corresponds to the ice accumulation conditions in most airspace in the northern temperate zone. Aircraft that meet this requirement can basically fly safely under all normal climate conditions.

Category 4 anti-icing capabilities are equivalent to additional questions, and only aircraft expected to be used in environments with more severe ice accumulation risks need to be completed.

The tower commander looked back at Chang Haonan who was standing behind him.

The latter hesitated for a few seconds, then nodded.

"Test flight plan approved!"

…

After receiving the news that the plan was approved, the two planes turned around and plunged into the thick clouds.

Soon, a dense layer of thin ice formed on the surface of the plane, blocking everyone's view of the outside.

Under normal circumstances, aircraft will deliberately avoid this obviously very dangerous airspace, so whether it is an engineer taking off randomly or a experienced test pilot, this can be said to be a quite special experience.

Especially the navigator cabin on the nose of the Y-8 aircraft, the 270° field of view is completely wrapped in ice. The navigator reported that he felt like he was in an Eskimo igloo.

However, as the ice became thicker and thicker, the freshness gradually wore off, and the pilots already felt that the aircraft became increasingly difficult to control.

In the cabin at the back, Lin Guofan was staring at the picture on the laptop screen, fearing that he had misread the position of the ice thickness scale.

According to previous simulations conducted by Chang Haonan, in normal configuration and horizontal flight, the ice thickness on the unprotected leading edge of the aircraft wing should reach 7cm to meet the test standard.

"The ice accumulation conditions have met the requirements, and the maneuvering flight test has begun!"

Since it was impossible to communicate with the tower in the clouds, Lin Guofan could only give instructions to the two aircraft together.

"Wait...this is crazy."

Colombo's voice came over the radio:

"I just saw on my computer that the water content in the outside atmosphere has exceeded 4g/m! This... this is four times higher than the data stipulated by the FAA!"

"You are right, Mr. Colombo, but we are not the FAA, we are CCAR."

Lin Guofan said into the microphone in his hand.

"But...but why is it so extreme? There is no such extreme situation except for snowstorms, and it is impossible for planes to take off in snowstorms!"

There was some trembling in Colombo's voice, as if he regretted following him at this moment.

"Of course it's for safety. Don't worry, we have the best anti-icing system in the world to ensure your safety."

"Besides, it's too late to say anything now. We can't throw you out of the cabin."

After Lin Guofan finished speaking, he did not talk to Colombo again, but directly ordered:

"Start circling steadily horizontally."

The pilots of the two aircraft carefully controlled the rudder surfaces and allowed the aircraft to start a stable circling at a 40° slope to the right.

"I...I saw that the wings of this plane were vibrating to a great extent. Is it really...is there no problem?"

Colombo, who was inside the MA-60 cabin, asked the mechanic next to him with a pale face.

The latter looked up calmly and glanced at the screen of the other camera, then looked back at the laptop in front of him: "It doesn't matter, that's our active vibration control system at work."

"Active flutter control?"

Perhaps because of nervousness, or perhaps because of the cold, Colombo seems particularly talkative today: ""

"Yes, just like... uh, just like active noise reduction, using controllable flutter to offset uncontrollable flutter. This is also the core technology of our MA60. Haven't you seen the brochure of our aircraft? Well, it’s all written above.”

"Who would read that kind of advertising? You are probably the first aircraft manufacturer to make the promotional brochure and flight manual the same thing..."

Colombo's teeth were already chattering.

"It seems that we still have a lot to learn from you in this aspect..."

At the same time, Lin Guofan on another plane had operated a high-speed camera to capture all the required ice growth images.

Compared with previous computer simulation results, they are almost completely consistent.

"call--"

He breathed a sigh of relief.

To say that I wasn’t nervous about taking off would be a lie.

In fact, until he was capturing the ice accumulation just now, Lin Guofan found that his hands were shaking slightly.

However, the design of the aircraft anti-icing system is based on the simulation of the severity of ice accumulation at different locations. Since the simulation results have no problems, it means that the entire de-icing device should also have no problems.

"The circling flight and roll subject is over, turn on all de-icing systems!"

…

Since they had been unable to contact the crew for nearly half an hour, the atmosphere inside the Nanzheng Airport control tower was a little anxious.

Every second is as long as an hour

It's one thing to have confidence in the anti-icing system, but not being able to hear the pilot's voice is always unsettling.

Especially Zhu Lan, who was worried about her husband, had been standing in the corner like a sculpture for a long time.

"Unit 01 report."

The sudden clear voice of conversation made everyone look happy.

"The maneuvering test flight procedures in the landing configuration, standby configuration and approach configuration have been completed. The anti-icing system is working normally and fully meets the test flight qualification criteria. Our two-plane formation is ready to return!"

Zhu Lan, who was leaning against the wall, suddenly relaxed and fell directly onto the sofa next to him.

Liang Shaoxiu, who had been tense for more than half a month, was completely relieved and called the deputy next to him:

"Notify the manufacturing workshop to replace the other three Y-8Js with new anti-icing systems as quickly as possible. The finalization schedule of the equipment must not be delayed!"

Chang Haonan, on the other hand, set his sights in the direction of the assembly workshop.

There are several other Y-8F platforms waiting for delivery parked there.

He stood in front of the floor-to-ceiling window of the tower and murmured in a voice that only he could hear:

"In this way, it turns out that the tragedies in history will never happen again..."