Soon after, the prototype 01 finally appeared in the eyes of everyone in the tower.

Through the high-powered telescope, the commander was able to see that the right side of the fuselage of the aircraft had been deformed, and that the tail nozzle part of the right engine had also been severely damaged.

However, the intake part of the airway was not structurally damaged to the naked eye, so it is unlikely that the accident was caused by a bird hit.

"The altitude is 120, the speed is 427, the visual condition of the tower is good, the aircraft attitude is stable, but the descent rate and approach speed are slightly faster."

Lin Tingguang used all his strength to pull the control stick and change the plane out of the shallow dive attitude.

With no last-minute descent rate and landing speed guaranteed, he had to give priority to the more stout rear landing gear, even though there was some risk of stalling.

At this moment, Lin Tingguang's entire world was left with only the runway and his own plane, and nothing else.

Even the sound of the tower commander reporting flight data in the headset gradually blurred.

At the moment when there were still a few meters left at the altitude and the plane was about to land, Lin Tingguang opened the plane's parachute in midair.

"Squeak—"

Prototype 01 was towed into the maintenance hangar immediately after landing, and the maintenance crew had completed the ground inspection.

But in any case, this risky move allowed him to reduce his landing speed to a safe range, and he could use almost the entire length of the runway.

In the end, the prototype of No. 01 was stopped dozens of meters in front of the barricade net that had been laid long ago.

"I'm fine, I can walk by myself...... Lin Tingguang took off his flying helmet and wanted to stand up, but in the end he was thrown directly onto the stretcher, but judging from his voice and the strength of the struggle just now, it should be fine.

Yan Zhongzhong, in particular, closed his eyes in pain.

And it's not caused by external reasons such as hitting birds.

Although judging from the current situation, there is no direct relationship between the follow-up airway of this accident, the rules and regulations are like this, and any possible loopholes must not be missed.

That night, more than 20 people, including Yan Zhongzhong and Yang Fenghat, landed at Yanliang Airport on a Y-7 plane.

"I don't have two days left to think about it now."

After a hasty dinner, the power joint research team devoted itself to the analysis and sorting of the test flight data.

……

In 1996, the regulations for soldier service had not been changed, and Lin Gang's military rank was the highest fourth-class sergeant major among the 13th class of soldiers.

There may be many factors that induce surge, but the root cause, or the essence of surge, is that there is a flow separation of the air flow on the back of the compressor blades, and this separation develops with the high-speed rotation of the compressor impeller to the entire blade channel.

A gasp was heard from the crowd.

The emergency response team, which had already been on standby, also swarmed up, and the fire truck began to spray water on the right engine, which was still slightly smoking, and the ambulance team opened the cockpit canopy of the plane from the outside and lifted Lin Tingguang out of the cockpit.

Yan Zhongzhong nodded slowly.

For the problem of surge, the most important task is, of course, to determine where the first surge occurred based on the test flight data.

Therefore, he asked the comrades of the test flight institute to ask for the flight status data of the prototype No. 01 before and after the surge accident.

This is undoubtedly a major blow to him and the entire 606 Institute.

Soon, Li Zhengqi, the person in charge of the flight test center, brought a ground crew carrying four thick crutches and two horizontal bars to Chang Haonan and the others.

By analogy, it is a bit like the engine is "coughing", but this cough is extremely contagious, once a surge occurs in a certain part of the compressor, it will affect the entire or even multi-stage blades in a short period of time, affect the working state of the entire compressor, and cause irreversible damage to the compressor structure.

Although the cause of the failure has not yet been finally determined, according to the judgment of the test flight commander on Yan Liang's side, it should be that the engine has failed in the air.

Therefore, he decided to take advantage of the comrades of the power joint research group to find the location of the fault and try to see if he could calculate the unstable working boundary of the engine.

"This is Sergeant Major Lin Gang, the most experienced ground service veteran on our side."

The latter was also watching him at the same time.

Opening a parachute in the air at the last moment before landing was a trick taught to him by Soviet instructors when Lin Tingguang was learning to fly the Su-27, but he really hadn't tried it on other aircraft before.

After Lin Gang finished his report, Li Zhengqi added the situation described by the test pilot next to him:

The tower, which had been in a heavy atmosphere just now, instantly resounded with cheers.

"Shhhh

"When the failure occurred, the surface speed of the aircraft was larger, the number of m was located near 1.1, the height was greater than 2km and less than 6km, the inlet slope plate was involved in the work, the pilot was axial impulse in the process of controlling the throttle deceleration, and was forced to push the throttle for a short time.

Lin Gang saluted, then turned to the No. 01 prototype and began to report:

However, if the pilot's handling of the surge is not reasonable and timely, resulting in the fuel that is not fully burned in the combustion chamber being discharged backwards, and spontaneous combustion occurs after the turbine after encountering the hot gas, it is even more likely to burn the entire aircraft.

The people of the 606 institute are responsible for the engine part, and the people of the 601 institute are in charge of the intake part -

With such severe engine damage, if not a bird hit, then it could only be a surge.

Such setbacks don't change the other party's mind, so there is no need to worry about anything.

The wheels made contact with the runway, sending up a puff of white smoke.

There was a dangerous situation during the test flight, which led to the news that the No. 01 prototype finally made a forced landing, and soon reached Shengjing.

As for the compressor design data of the turbojet 14 engine, thanks to the fact that the digitization and parametric modeling had been completed before, it was also brought with it when I rushed from Shengjing.

After a few seconds, Yan Zhongzhong took a few deep breaths, reopened his eyes, and looked at Chang Haonan next to him.

This is a job that relies heavily on experience, and Chang Haonan knows that he can't help much.

Chang Haonan's tone did not waver at all:

That's right, it happens to be the problem of impeller mechanical flow separation that Chang Haonan has been studying before.

If, like this accident, there is a surge in the afterburner process, then the compressor is easy to generate negative pressure in the process of "coughing", resulting in the reverse flow of ultra-high temperature gas in the combustion chamber, and finally destroying the entire engine.

"According to the preliminary inspection carried out so far, 13 pieces of the first stage compressor of the left engine were injured to varying degrees in visual inspection, and the tie rod connecting the rocker arm of the hydraulic actuator of the adjusting plate and the rear adjusting plate was broken at the root of the earring bolt; misalignment of the engine and the intake duct transfer section; The hole finder found that the left and right engine diverter rings were torn. ”

For the personnel of the flight department, keeping the plane is something to celebrate.

It happened that the work coordination meeting had just ended, and Yan Zhongzhong said that Chang Haonan would be given two days to think about the final decision.

Therefore, Lin Tingguang's decision-making after this accident was close to perfect, and he almost completely retained the entire failed engine, which can be regarded as a blessing in misfortune.

When the three of them heard the news, the expressions on their faces were stunned.

But he chose to fly thousands of miles to Yan Liang with Yan Zhongzhong, and naturally he would not watch the excitement.

"The pilot reported that the engine malfunctioned during the afterburner after exiting the rush to the gauge speed, and there was no obvious sound of air flow pulsation in the engine intake tract before the failure."

To put it simply, surge refers to the reciprocating airflow caused by the separation of the compressor airflow, resulting in a high-amplitude or low-amplitude oscillation along the axis of the compressor.

"Let's go to Yan Liang together."