It is just daylight at 7:30 am at Shenyang Taoxian International Airport. Zhao Xuesong, wearing a helmet, is standing on a 2-meter-high vehicle and spraying de-icing fluid toward an airplane. In the chilliness of -19 C air, the liquid turns into frozen fog.

This is Zhao's routine work during the four-month winter in Shenyang, capital of Liaoning province. When it snows or the air's humidity is heavy, Zhao and his colleagues have to service almost 20 airplanes each day, taking about 30 minutes each time.

The 36-year-old is an engineer of Shenyang Aircraft Maintenance & Overhaul Base of China Southern Air Holding Company. He has been engaged in this work for 12 years.

According to him, ice and snow on airfoils will add resistance and violate aerodynamic structure, which will damage an airplane's lift, the force holds it in the air. Therefore, de-icing is an essential task before a plane takes off, to avoid a flight accident.

Sometimes, Zhao has to touch the planes first, to judge the thickness of the ice, before choosing the proper concentration of de-icing fluid. Because he works long hours outdoors, his hands and face usually get frostbitten.

"It's nothing. I'm used to it already," Zhao says with a smile, adding that he loves his work.

De-icing is just a small part of Zhao's work. He is an "outpatient doctor" of aircraft. He examines each plane after it lands or before it takes off to determine whether it needs maintenance or overhaul.

Because the lives of passengers are at stake, the work has strict operation procedures. "Any errors are not allowed. Even if only one screw is missing, we must find it. If it is lost in the engine, it may cause a terrible accident," Zhao explains.

Thus, Zhao has to count the tools after each maintenance job according to a list. And this forms a habit, or even some degree of obsessive-compulsive disorder, in his life.

According to Wang Dan, his wife, Zhao likes listing everything on a paper before or after he does something. "Even when he's shopping, he will list things to bring with him, such as keys, mobile phones and so on. As long as the list goes with him, there's no worry about losing our belongings."

The strict working requirements have made Zhao always tense. To relax, he likes to play football with his colleagues during free time. "I feel the pressure is released with the sweat."

However, due to long working hours, Zhao looks tired with a pair of obvious pouches under his eyes. "It's normal for us to work overnight. Holiday seasons are the busiest time for us, because flights are more frequent."

"His working time is irregular. I have to carry the burden of taking care of our son and parents," Wang says.

Zhao feels guilty about that. He hasn't applied for annual leaves for two years and spends most of his time at work. "I used to think my son is too young to travel with us. Now he is 5 years old. I hope I can spend more time with him and take him out for tours this year," Zhao says, his voice becoming tender.

For the coming Spring Festival holiday, he has to stick to his post.

"I have one day off on Lunar New Year's Eve, so I can make dumplings with my family. That's good enough," says the optimist.

Contact the writers through wuyong@chinadaily.com.cn.