A Pakistani JF-17 Thunder fighter jet arrives at a Chinese airport to take part in the "Shaheen VI" joint training exercises in China, September 7, 2017. Photo: Xinhua

The close cooperation between China and Pakistan was highlighted by the recent delivery of the first overhauled JF-17 fighter jet under a project that experts said on Tuesday will benefit Pakistan's aviation industry.

Changsha 5712 Aircraft Industry Co Ltd under the state-owned Aviation Industry Corporation of China (AVIC) reassembled the overhauled JF-17 and delivered it to its Pakistani client in March, China Aviation News revealed on Monday.

This is also the first time AVIC has overhauled a made-for-export third generation fighter, or fourth generation according to another widely used standard, the report said.

"The first [JF-17] overhaul marks an important milestone [in the JF-17 project]," Fu Qianshao, a Chinese air defense expert, told the Global Times on Tuesday.

The first overhaul represents the trial-and-error phase of the project and provided experience in establishing standards for other JF-17 overhauls in the future, according to Fu.

Jointly developed and manufactured by China and Pakistan, the single-engine multi-role light fighter jet JF-17 made its maiden flight in 2003. The first JF-17s were delivered to Pakistani clients in 2007 and a number of them were later commissioned by the Pakistan Air Force.   After a decade of use, it was time for the first JF-17s to undergo overhauls, military analysts said.

A contract was signed in 2016 and the first overhaul started in November 2017. The overhauled aircraft made its first test flight in October 2018, reports said.

An overhaul includes major maintenance featuring repairs and replacement of old components including the airframe and engine, said Fu. While standard, regular maintenance could be done by the military, an overhaul usually needs to be conducted by a designated and more capable supplier due to higher complexity, he said.

Such an overhaul can ensure flight safety after years of use, Fu said. It might also equip the aircraft with newer technologies that enhance its capability, or prolong the aircraft's lifespan, he said.

The experienced overhaul team at AVIC used a reliability-oriented maintenance model, keeping the maintenance cycle short and costs low, the China Aviation News report said.

Pakistan sent dozens of trainees to China, who had close communication and built deep friendships with Chinese engineers during the overhaul process, the report said.

Fu said since procedures and standards for the overhaul have been established, future overhauls on other JF-17s could be done by Pakistani personnel.

"Under the framework of China-Pakistan cooperation, Pakistan's aviation industry will continue to develop," Fu noted.

A Block 3 variant of the JF-17 is under development, which is expected to be much more powerful than the previous two blocks thanks to a new China-developed active electronically scanned array radar, reports said.