TAIPEI, Taiwan — China launched its first domestically built aircraft carrier to begin sea trials on Sunday, reaching another milestone in the expansion of the country’s navy.
The aircraft carrier, as yet unnamed, left its berth at a shipyard in the northeastern port of Dalian after a blow of its horn and a display of fireworks, according to reports in state news media.
The Chinese Navy — officially the People’s Liberation Army Navy — already has one operational carrier, the Liaoning, which it bought unfinished from Ukraine after the collapse of the Soviet Union. That ship joined the Chinese fleet in 2012 and began its first operations four years later, putting China in the small group of seafaring powers that maintain aircraft carriers, led by the United States, which has 11.
The Liaoning, which appears to serve as a training vessel as much as a combat ship, was the centerpiece of a naval parade of 48 ships attended last month by China’s leader, Xi Jinping. The following week, it led a carrier battle group in live-fire exercises in the Taiwan Strait and in the East China Sea.
Since taking office, Mr. Xi has driven an ambitious effort to modernize the country’s military, reducing the traditional focus on readying the ground forces of the People’s Liberation Army to defend against an invasion of the mainland and increasing the emphasis on technology-dependent naval, air and missile forces.
The new carrier, built by the Dalian Shipbuilding Industry Company, has a similar design to the Liaoning but has been modified and expanded, according to Chinese and foreign experts.
The Global Times, a Chinese newspaper, published a side-by-side comparison showing that the new carrier was slightly longer and wider, and saying that it would be able to carry 32 to 36 J-15 fighter jets, compared to 24 aboard the Liaoning.
Both displace 50,000 tons, compared to the newest American carrier, the Gerald R. Ford, which displaces twice that and can carry 75 aircraft. Unlike the nuclear-powered American carriers, the two Chinese ships use conventionally powered engines, limiting their range and ability to stay at sea.
“The main tests will be of the reliability and stability of the mechanical systems and related equipment,” an article on the website of the Chinese Ministry of National Defense said on Sunday, describing the goals of the sea trials, which could last as long as a year.
Aircraft carriers are costly and complex — and perhaps no longer as dominant as they once were. Some military experts say anti-ship missiles and other new weaponry have made carriers increasingly vulnerable, blunting the advantage they have had on the high seas since World War II.
They nonetheless remain a formidable display of power that can reach far beyond a country’s borders, giving them important symbolic value that China clearly desires as it seeks to expand its influence abroad.
China’s military is even more opaque than most, and the navy has not outlined its shipbuilding plans in any detail. According to several reports, however, the construction of a third carrier, with a different design, has already begun at the Jiangnan Shipyard in Shanghai.
The second carrier’s sea trials have long been expected, but the ship appeared to have encountered some delays. A flurry of reports in April suggested its trials were about to begin — only for the ship to remain at its berth in Dalian’s harbor.
“When there is good news about the next step, we will announce it first thing,” the defense ministry’s spokesman, Senior Col. Wu Qian, said at a news conference a few days later.
It remains unclear when the second carrier will be commissioned and officially become the fleet’s new flagship. Initial reports suggested it would be ready this year, but The Global Times reported on Sunday that it might not be ready until 2020.
Olivia Mitchell Ryan contributed research.