Jet closer to market-entry clearance(2)

International review

The Federal Aviation Administration, the US national aviation authority, also carried out a shadow review, to assess CAAC's capability, and randomly inspected 53 of the more than 300 CAAC experiments on the ARJ21, Shen said.

The FAA's review is ongoing, and the two authorities will sign a bilateral agreement to verify CAAC's assessment capability after the review is completed.

COMAC will also apply for airworthiness certification for the ARJ21 from the European Space Agency and, with approval from the FAA and the ESA, the Chinese manufactured aircraft will enter the international market.

COMAC deployed its outfield test team to Yanliang in 2009, together with the aircraft, and most of the ground test equipment was made there.

"I thought the work in Yanliang would last two or three years originally," said Ni Guomin, head of the team's technical support group.

The 68-year-old, who was supposed to retire years ago, was assigned to Yanliang in August 2009 to lead an 80-strong group consisting mainly of young engineers.

From the beginning, Ni and his apprentices were kept very busy as many problems were found with the plane, he said, and they had to work on weekends.

Another challenge for Ni was teaching his younger colleagues.

"We jokingly described it as 'grandpas teaching grandsons'," he said.

As the tests progressed, the young engineers became more experienced and the workload also eased.

Airplane problems became rare in 2014 and the staff could relax on weekends, Ni said.

Besides the staff of COMAC, the ARJ21's suppliers were also involved in the airworthiness examinations.

The jet was sent to the AVIC Aircraft Strength Research Institute, which is the only research center dedicated to aircraft strength in China, on Sept 28, 2007. Even now, although the aircraft has received airworthiness certification, an ARJ21 is still undergoing fatigue tests at the institute.

Takeoffs and landings are simulated on the aircraft to check its life span, which is designed to be 50,000 flying hours over 20 years.

The fatigue testing will take seven to eight years, as it simulates the aircraft's full working life, said Qiang Baoping, deputy director and chief engineer at the institute.

The aircraft also went through a three-and-a-half year static test in the institute to check its design strength.

"It was also the first time for us to work on passenger aircraft airworthiness certification," Qiang said.

The institute improved some of its equipment and test methods while working on the ARJ21 program, he said.

The ARJ21 is considered the start of China's passenger aircraft manufacturing, and all stakeholders, including the authority, manufacturers and suppliers, continue to work on the C919 and possibly the C929 - a domestically made wide-body aircraft.

The strength research institute has built a facility for the C919 in Shanghai, next to the aircraft's assembly line.

Engineer Guo and his colleagues still take care of the aircraft in Yanliang, but some may be assigned to Shanghai to work on the C919.

"The C919 will take a shorter time to get airworthiness certification, as we now have experience from the ARJ21," CAAC's Shen said.

Trying times for local industry

Since a Chinese engineer named Feng Ru set up a company in Guangdong province to build aircraft in 1909, the Chinese aviation industry has experienced twists and turns in the past 105 years.

After World War II, the global aviation industry moved from military to civil aviation, and China tried to catch up with its Y10 four-engine narrow-body aircraft, developed in Shanghai in the 1970s.

However, the program was canceled in the early 1980s.

"We did not have airworthiness standards or test pilots for the Y10, and the authorities did not have an airworthiness division at that time," said Cheng Bushi, deputy chief designer of the Y10, explaining why the aircraft was not certified although it made several test flights.

The Y10 program alerted authorities to the importance of airworthiness, and Commercial Aircraft Corp of China established an airworthiness division in 1987, Cheng said.

China established its airworthiness certification system in the following years and awarded certifications based on various regulations to some homemade aircraft, including the MA60 and Y12.

As the only Chinese aircraft to attain airworthiness certification based on the CCAR-25 standard, which is for transport aircraft of takeoff weight of 5,700 kilograms or more, it took the ARJ21 six years to obtain the certification, surpassing the Boeing 787 for the longest airworthiness process in the world.

A lack of experience, human resources and capital was among the reasons behind the aircraft's long journey to certification.

Safety steps

Required steps before new aircraft are approved:

. Airworthiness certificate:

The national aviation authority issues this to an aircraft to certify that it is airworthy according to its design type. Airworthy means the aircraft can fly safely, including takeoffs and landings. Usually, the aircraft has to go through three major tests to prove its airworthiness, including type and production standards.

. Shadow review:

A necessary step for the US Federal Aviation Administration before entering into bilateral safety agreements. The shadow review aims to reduce repetitive work on airworthiness based on the CAAR-25 standard. The priority is to assess the Chinese civil aviation authority's regulations and ability to certify airworthiness. The FAA also reviews the aviation authority's understanding and application of US airworthiness standards.

. Ice protection system test:

An important item for certification of commercial aircraft, as ice formation is a major threat to flights. Both the Chinese and US authorities have strict requirements in this area. The testing team in China waited four years without any results. The ARJ21 manufacturer applied to fly the aircraft to North America, although it was a challenge for the regional jet to fly an international route.

The testing team spent half a month checking off all the required items of the ice protection system in Canada, and the aircraft made its maiden flight around the world in 2014.