China Tests World's Largest Flying Boat

This week, the Aviation Industry Corporation of China (AVIC) completed the first sea-based flight test for the AG600 "Kunlong," the world's largest currently-operating flying boat. 

In a flight test, Sunday in the city of Zhuhai, China, the AG600 took off and carried out a half-hour circuit before returning for a water landing. It was the second waterborne test for the prototype after a 2018 flight from a reservoir outside Jingmen, Hubei province.

The 50-tonne aircraft has an operating range of about 2,500 nautical miles - enough to reach remote, contested islands in the South China Sea and fly back to the mainland without refueling. It has enough capacity to carry 50 passengers and can stay aloft for up to 12 hours at a time. Its waterborne operation is restricted to a maximum wave height of two meters; in addition to a hydrodynamic hull form for water landings, it has landing gear for operations from paved runways.

According to AVIC, one of the aircraft's key functions is to search and rescue. AVIC also intends to use the Kunlong in an aerial firefighting role, and it says that it will focus on this capability for deployment by 2023. 

Though the flying boat concept has a long and rich history, only a few nations still build and operate them, and the Kunlong is the largest today. The biggest flying boat ever built - the plywood-framed Hughes H-4 Hercules, known best as the "Spruce Goose" or "Flying Lumberyard" - famously flew for less than 30 seconds, and it now resides at the Evergreen Aviation and Space Museum in Oregon. 

There are several other actively-serving examples in the class: Japanese company ShinMaywa builds a large four-engined large seaplane, the US-2, which operates in SAR and aerial firefighting roles for the Japan Maritime Self Defense Force. Thailand, India, and Indonesia have all expressed interest in procuring the design, driven in part by concerns over China's maritime expansionism in the Indo-Pacific. 

The Russian Beriev Be-200 Altair - a rare jet-powered amphibious aircraft design - is in service with Russia's Ministry of Emergency Situations, and it has worked internationally on contract firefighting missions in Indonesia, Greece, and Portugal. China has purchased two of these Russian planes with options for two more.

via ME