Two J-20s howling through the sky with their missile bays open, each showcasing six missiles as the stealth fighter jets celebrated the 69th birthday of the Chinese People's Liberation Army Air Force on the last day of the Airshow China 2018 in Zhuhai, Guangdong Province on Sunday. Photo: Cui Meng/GT

Despite having to hide its munitions in an internal weapons bay to achieve a high level of stealth, China's J-20 stealth fighter jet can still launch missiles under extreme battlefield environments, bringing tactical advantages in combat, the chief test pilot of the aircraft revealed recently.

It took nearly seven years for the J-20 to be commissioned into the Chinese People's Liberation Army (PLA) Air Force since its maiden flight in 2011, and during this period, the aircraft underwent a series of combat-oriented test flights that challenged its limits and validated the warplane's safety under all kinds of extreme conditions, Li Gang, the chief test pilot of the J-20, said in an interview with China Central Television (CCTV) that was aired during the National Day holidays this week.

One of the biggest challenges Li faced during the test flights was  simulating the emergency launch of missiles within the weapons bay under extreme battlefield conditions, CCTV reported.

The test involved opening the bay hatch at the belly of the aircraft and launching a missile while performing high-G rolling maneuvers, Li said.

"It takes some time for the missile to launch after I press the launch button. If an enemy missile were to come for me during this period, I would have to make emergency maneuvers at high speed and high G forces. In this scenario, my missile needs to be ejected from the weapons bay without hitting my own aircraft and without leading to any danger," Li said.

The test was very risky, but it had to be done under real conditions, so the aircraft could be handed over to combat forces knowing full well that it is a functional and effective weapon, said the veteran test pilot.

The test flight confirmed that the J-20 can not only launch missiles under optimal conditions, but also under emergency and extreme conditions, which can bring important tactical advantages, a Chinese military expert who requested anonymity told the Global Times on Friday.

A good fighter plane can attack while being attacked, the expert said.

The test flights showed that the J-20's weapons bay and weapons separation system are well designed and have been validated through practical application, the expert said.

The J-20 opened its weapons bays and displayed its missiles for the first time in front of the public at the Airshow China 2018 in Zhuhai, South China's Guangdong Province.

The flight performance showed that the J-20 has a main weapons bay under its belly capable of holding at least four PL-15 beyond-visual-range missiles, and a side bay on each of the two sides of the aircraft capable of holding at least one PL-10 short-range combat missile each.

Stealth aircraft uses weapons bay to hide weapons within their fuselages to reduce radar cross-section and avoid detection, while also providing better aerodynamics, analysts said.