Test-flight time for China’s latest, largest amphibious plane prototype

China is preparing to test-fly a new prototype of its largest amphibious plane, the AG600, that will be able to cover all of the South China Sea.

The four engines of the AG600-1003 prototype were tested on Tuesday, paving the way for test flights, according to its developer, China Aviation Industry General Aircraft. Its assembly was completed in December.

The previous prototypes of the aircraft, known as the Kunlong, conducted maiden flights over land in 2017 and at sea in 2020.

“The AG600 aircraft has completed more than 100 hours of scientific test flights, accumulating and acquiring a large amount of flight test data,” the developer said on social media.

“The research team improved the key design theories, methods and verifications such as in aerodynamics and hydrodynamics for the amphibious aircraft and made further breakthroughs in the key technologies of amphibious aircraft design.”

China’s latest five-year plan, covering 2021 to 2025, identified the AG600 as a key programme because of the country’s urgent need for an emergency rescue aircraft, and especially the strategic requirement for equipment that can serve its far-reaching bases in the South China Sea.

The AG600 combines a plane with a boat underneath, and can take off and land on both land and water. It is designed for fighting forest fires, maritime patrols, and search and rescue. It could also be used for oceanic environment observation, resource exploration and transport between islands.

If deployed in the southern island province of Hainan, the aircraft would be capable of reaching anywhere in the South China Sea within four hours. It could also serve as a cargo or passenger carrier between the Chinese-controlled islands in the region.

With its boat underside, the AG600 can “ski” on water. In 20 seconds of skiing it can draw 12 tonnes of water into its tank – enough to spray over 4,000 square metres (43,000 sq ft) in a firefighting mission.

Once completed, the propeller-driven plane will be the world’s biggest amphibious aircraft, overtaking Japan’s US-2 and Russia’s BE-200.

Measuring 36.9 metres (121 feet) long with a 38.8-metre wingspan, it is similar in size to a Boeing 737. It can carry 50 passengers and fly at up to 500km/h (310 miles per hour), with a longest duration of 12 hours.

However, the AG600 faces the same technological bottleneck as other Chinese-developed planes: the engines. The turboprop engine fitted on this plane is the WJ-6, an outdated model based on the Soviet Ai-20 series from the 1950s.

Progress in developing the plane has caught up after being delayed by the Covid-19 pandemic, with one of its major research facilities being located in the outbreak’s initial epicentre of Hubei province.