Chapter 8 — Light Streaks Off The Runway

Truong Dieu Han did not send a plane to prove the airport wrong. She brought an optical observation set, placed it on a trailer and asked everyone to stand at the agreed distance from the runway.

“If we just take one beautiful photo, we will have a beautiful photo again,” Han said. “I want a series of images in different positions, same focal length, same time, same brightness.”

Tong listened in the operating room, his face expressionless. “The opening show is nine days away.”

“And the test takes one session,” Han replied.

“The company bears the cost?”

“Partly.”

“The rest?”

“The airport accepts.”

“The cost of observing is smaller than the cost of guessing,” Nghi said.

Tong turned to her. “Are you learning my sayings?”

“No. I'm using the cost sheet.”

Uyen prepares the stand. She checked the device number, battery, memory card and placement angle. Establishing a restricted area on the apron. Lan walked around the ditch, placing stakes so the operator wouldn't stray off the dry path. Duy is at the tower, in charge of confirming when there are no aircraft approaching.

The test session is scheduled for 7:00 p.m. The sky has been cloudy since morning. The sea breeze hit the station windows, carrying with it the smell of salt and sand. A cold storage employee said that if the inspection is prolonged, the nightly vehicle will have to be rescheduled.

Kha replied: "There is no night flight today."

“Tomorrow yes.”

“So today we have to do it right.”

Suspected that Kha had stopped asking who was responsible. He began to ask which landmarks had to be kept.

At exactly 7:00 p.m., the side lights turned on at a low level. The lens is located at the southern observation mark. From the first photo, the row of lights looks even. The second photo, taken to the west, shows that the last four bright spots are not on the same line. Han asked not to comment immediately. Uyen records the time, location, light level and wind direction.

Tong stood behind the screen and asked: "Could the difference be due to the lens?"

Han replied: "It's possible. So there is a photo for reference."

They changed the device to another camera. Similar results, but smaller deviations. Do not breathe a sigh of relief. Two devices seeing the same signal only says that the sign exists, not the cause.

Lan asked to build a thin rope along the edge of the real runway. When the camera rotates, the wire shows that the last four lights are slightly offset. Han enlarges the photo without using color filters.

“This is incorrect geometry,” Nghi said.

Tong asked: "What level is not right?"

Han looked at her. "I'm not the one who sets the airport's technical threshold. But I won't sign that this image is problem-free."

Tong went out. He looked from three landmarks, changed positions, bent down to the painted road, then looked at the lights. From the ground, the deflection streak almost disappears.

“If I stand here, I see a line,” he said.

“Pilots don't look from a single point,” Duy replied over the radio from the tower. “The perspective changes as the plane approaches.”

“Do you have pilot data?”

“There are old reports.”

“Old reports are not today's test.”

“But it matches the description.”

Nghi did not let the conversation turn into an argument over the radio. She asked Duy to record each sentence in the diary.

At 8:15 p.m., they turned off the W-3 circuit and turned it back on via backup power. During the first eight seconds, the western lights flashed intermittently. The last two lights are half a beat slower, then catch up. The control panel does not indicate a problem.

Uyen called out: "Miss Nghi, this photo is different."

In the photo, the light streak is more obvious. When transferring load from the main source to the generator, the system not only keeps the geometry wrong; it makes me feel out of tune first moment.

Kha looked at the screen. “Is this what Mr. Duy said?”

“Partly,” Nghi replied.

Tong asked: "Could it be because the camera took pictures when the lights were not stable?"

“Maybe,” Nghi said. “But that is the exploitation condition that needs to be checked, not the reason for removing photos.”

Han turned to Tong. “If the light is not stable after switching power, the company needs to know the stabilization time and confirmation process.”

Tong crossed his arms. “I cannot represent to the province that a set of lights needs to be viewed from eight angles while they are waiting for promotional photos.”

“So don't show promotional photos,” Han said.

The air is tense. Han does not have the right to close the airport, Tong does not have the right to edit the data to make it look beautiful, Nghi does not have the right to decide the flight schedule alone. Each person stands in the right place, but those places collide with each other.

Uyen suddenly spoke up: "If we check all eight corners, we can determine which points repeat."

Everyone turned to her.

Uyen swallowed saliva. "I'm not saying a conclusion. I'm saying we need the same position matrix. If at any corner the deviation disappears, we know it's a perspective problem. If it's still there at all angles, we know we need to measure the landmark again."

Han nodded. "Correct."

Tong asked: "What's your apprentice's name?"

“Pham Nha Uyen.”

“Are you going to make that matrix?”

Uyen looked at Nghi. Nghi did not nod, just said: "I heard the request."

Uyen replied: "Yes. I will do it."

They continued until 10 p.m. Each location is coded. Each photo retains its original data. Nghi requested that "bad" photos not be deleted. Record the settlement next to each pile. Kha makes a list of vehicles that have traveled near the inspection area. Only records power transfer time and radio status.

When it was all over, it started to rain dust. Han removed the memory card and sealed it in a bag.

“I'll send you copies,” she said.

Tong asked: "And the conclusion?"

“Not yet.”

“The company needs to know if it will run the simulation tomorrow.”

Han looked at Nghi, then replied: "I need to read the data."

I doubt I understand that sentence. Not a refusal to schedule. It is a refusal to use the calendar to force conclusions.

In the technical room, Uyen created a matrix table on the computer. The columns are angle, source condition, light level, background state, image. The last four lights have abnormal markings in five out of eight locations. When the backup power is on, the mark appears in seven positions.

“Sister Nghi,” Uyen said, “if this is a lens illusion, it must change without the source.”

Nghi looked at the board. "Correct."

“So I got…”

“There is a connection that needs checking.”

Uyen smiled tiredly. “I won't let you use the word cause.”

"Not yet."

Outside in the yard, a guard turned off the row of lights on command. The last four lights went out last, leaving reflective streaks on the road surface like a second runway.

The test flight did not take off. But the data left the ground another way: it passed through eight angles, three recorders, and a system that could no longer be called normal just because it remained lit.

In the training room, Uyen presented photos to a group that had not yet participated in the field. An employee looked at the sixth photo and said: "If you show me this photo, I will say the light is wrong."

Uyen replied: "It's a conditional photo. To use it, you have to see other photos, location, source and landmark."

“So is this photo valuable?”

“Yes, but not enough on its own.”

Nghi listened and realized Uyen had learned not to turn evidence into a convenient story.

Han sent the company's simulation copy. The pilot did not say the system was absolutely dangerous. He marked the times when the edge light image was difficult to distinguish from reflective edges, especially when switching power and wet road surfaces. He suggested that the airport clearly state the amount of time the system needs to stabilize after power transfer, but do not use this assessment as a substitute for cable inspection.

Tong asked: "If the pilot says it's difficult but not impossible, can we open it?"

Han replied: "The level of difficulty depends on the conditions. If we don't know which condition makes it more difficult, the answer cannot be used."

Duy added: “And the pilot is not the one asked to test the limits of the system to help us complete the paperwork.”

A young employee asked why people make opening routes complicated. Han looked through the glass window. “Because a flight is a chain, the weak link is not where people take promotional photos.”

That night, Tong allowed the load simulator to be tested, but did not allow the lights to be turned on at mining level when the ground was wet. Nghi agrees. They set up cameras at four landmarks, with no one standing in the area. Light rain makes the photo difficult to read. Uyen suggested waiting for the rain to stop, Lan suggested recording the current conditions before waiting.

“If we wait for good conditions, we will only know the system in good conditions,” Lan said.

They captured both phases. Rainy photos show clear reflective streaks, dry photos show that geometric streaks are still present but slight. Nghi marked two types, do not mix.

Reportedly a contractor vehicle had stopped outside the area but its headlights were shining into the yard. Han asked if an external light source caused the image to be wrong. Nghi asked to turn off the car's lights, take a photo, and record the time. The results still have deviations.

“That eliminates a secondary source,” Uyen said.

“Part of the secondary source,” Nghi corrected.

“You don't give me complete happiness.”

"Be happy. Just write down what you're happy about."

When everyone collected their devices, Tong received a call from the province. They want beautiful photos to include in online brochures. Tong said he could not provide promotional photos before concluding. The other person asked why.

“Because the photo does not fully reflect the conditions,” Tong replied.

After hanging up, he said, “I just lost my chance to get a good photo.”

Nghi asked: "Are you sorry?"

“Yes. But I don't want a pretty photo to become a confirmation that I haven't signed.”

Uyen saved the photo to storage. She creates a “no media” folder for photos that are in unfinished condition. Kha asked if he had to hide it.

“No,” she replied. “There is a label to prevent misuse.”

Duy said over the radio: "I like this sentence."

Nearly midnight, Han left the airport. Before leaving, she told Nghi: "I won't force you to open it. But I need you to clarify if the data is enough."

“I also need you to clarify if the company cannot wait.”

"Okay."

Both sides do not promise results. Just promise not to use silence to make the other person guess.

In the storage cabinet, Nghi put red maps, blue maps, observation photos and old reports in the same box. She wrote on the side of the box: “W-3 — historical appendix not separated.”

History does not make the lights brighter. But if you separate it, the person who fixes it later will think the error started from the day they got the job.

The test flight did not take off. The data was enough to turn a demonstration into a demonstration, and that was the first thing Vam Chan airport got right before getting a real plane to believe in.