China’s first domestically built aircraft carrier has now completed four sea trials since its maiden voyage in May last year, including exercises in December that mimicked battle conditions, but speculation is growing that it has not all been plain sailing.

Known at this point only as the Type 001A, the 55,000-ton vessel was launched in April 2017 and many observers have been impressed by the speed at which it has reached the test milestones that will take the carrier to eventual deployment. In the exercises in December, the vessel carried true-to-life replicas of J-16s and other shipborne warplanes, and its formal commission is now expected by October this year.

Yet while the carrier makes swift progress through the sea trials, questions are still being asked about its design and construction.

China’s indigenous carrier the Type 001A was seen leaving her dock in Dalian before her maiden sea trial in May last year. Photo: Reuters

Rumors of quality issues began to swirl around the carrier after Sun Bo, general manager of China Shipbuilding Industry Corp (CSIC), fell foul of Beijing’s graft-busters just one month after its maiden voyage. CSIC was the state-owned corporation that built the vessel.

Military affairs columnist Andrei Chang also raised questions about potential defects in the carrier’s power system – like its sister ship, the Soviet-made Liaoning, the Type 001A is propelled by steam turbines – and a possible imbalance in water displacement that may lead to a tilted flight deck.

Chang noted that the carrier had returned to a dry dock at the CSIC’s Dalian Shipyard right after its first five-day sea trial, remaining there for as long as three months, after probably encountering technical issues that required extensive repair work. These included checks of its propulsion system and the bottom of the hull. He said it was not common for a vessel in mint condition to be brought in for repairs straight after its maiden voyage.

Media outlets reported at the time that the carrier had been returned to the same dry dock where it was built: the gates were closed, water drained out and dockyard workers went back in action.

Others believe that the carrier simply needed a good clean on its bulbous bow and other sections of the hull to get rid of barnacles and debris, while there is also speculation that it may have needed some touching up on surface areas, such as newer layers of anti-corrosion paint.

The fact that the carrier was able to go back to sea for further trials in August, with navigation and propulsion systems being pushed to the limit, could indicate that the early glitches have been largely overcome.

We may find out soon, as the next voyage – its first this year – is now thought to be imminent. With only a few trials likely remaining before the handover to the People’s Liberation Army, defense chiefs will be looking for calmer seas through to October.