Feature: China creates "super hangar" to nest surging civil fleet

by Xinhua writer Hu Tao

BEIJING, March 25 (Xinhua) -- Legendary Chinese engineer Lu Ban is believed to have created a flying wooden bird in ancient times.

Today, Zhao Boyou claims he makes "nests" for aircraft.

"People need to rest after working hard. So do aircraft. Jumbos need spacious hangars," says Zhao, 47, vice chief structural engineer of China Aviation Planning and Design Institute (CAPDI) of the Aviation Industry Corporation of China, Ltd. (AVIC), the state-owned aviation giant.

His team is making a big column-free hangar for Beijing's new airport, which will be able to hold about 11 civil aircraft.

"We create hangars for aircraft 'health checks', maintenance, repairs and overhaul," says Zhao. The maintenance hangar for China Southern Airlines will set an Asian record. It will be 405 meters across, 100 meters deep, and have a clearance height of 30 meters.

It will be about 46 meters wider than the current Asian record holder: the A380 hangar at Beijing International Airport, also created by CAPDI.

"It will hold two A380 jumbos, three B777 wide-body aircraft and six narrow-bodies, such as the B737or A320," says Zhao, sketching a rectangular building. "And about 1,200-tonne maintenance facilities will be suspended from the roof."

BOOM TIME

CAPDI has designed more than 95 percent of civil aircraft maintenance hangars in China, and all the painting hangars.

China's civil aviation industry is mushrooming in fleet size and passenger and cargo loads.

At the end of 2017, the civil fleet stood at 3,296 aircraft and the industry logged more than 10 million flight hours for the first time, according to Civil Aviation Administration of China (CAAC).

"After arriving at your destination, have you ever thought of where the plane goes?" asks Zheng Yingping, executive deputy director of the Civil Aviation Engineering Design and Research Institute of CAPDI.

"It's the hangar, a place for aircraft rest and restoration for the next trip. Safety is the lifeline of civil aviation, and the hangar is a critical point to ensure safety," Zheng says.

Beijing's new airport, which will relieve pressure on Beijing International Airport, is sited 46 kilometers from the downtown area and is expected to start test operations in late 2019.

But more airports mean more pressure on construction land.

The long-span hangar is the "secret weapon", the most feasible and economical solution to meet the challenges, says Zheng.

SUPERSIZING

"We are exploring creative methods to make bigger, longer hangars, but lighter and stronger in structure," says Zhao. The long-span hangar is more than just a "big building with a massive roof."

It is a functional building with many cradles and suspension maintenance equipment, tailored to huge aircraft bodies and maintenance services.

An array of pipelines must supply power, water, ventilation, gas and other necessities.

"It is a huge challenge for engineers to balance strength and flexibility," says Zhao.

Numerous other factors such as costs, land area and time limits are also in their minds.

As hangars are mostly built near runways, height is severely restricted. However, traditional hangars have "big heads," a gate truss structure to support the roof.

But the cost of a "big head" for the super hangar was prohibitive.

"We tried and experimented time and again. Finally, we got a creative design that adopted high-strength cables for leverage," says Zhao.

The patented design could also use about 1,500 tonnes of steel less than the traditional design, enough to build a hangar roof the size of a football field.

CAPDI has previously set records with the 80-meter maintenance hangar in Guangzhou in 1985, the 352-meter A380 hanger in Beijing in 2005, and a group of hangars at Shanghai's Pudong Airport in 2006.

"China has ambitions to integrate into the global aviation industry chain. China-developed aircraft are flying overseas, and so are our creative designs and engineering services," says CAPDI chairman Lian Dawei.

"We've cast our eyes on the markets of Africa and Southeast Asia, supporting them to fly higher with 'China span' and 'China speed'." Enditem