* Strengthens capacity for world's second-largest navy to project power
* Construction of support vessels has lagged far behind combatant ships
* Support vessels increasingly needed for territorial patrols
* Aircraft allow fast deployment of troops, equipment
By David Lague
HONG KONG, Feb 26 (Reuters) - China is expanding its long-neglected fleet of supply ships and heavy-lift aircraft, bolstering its military prowess in support of missions to enforce claims over disputed territory and to defend Chinese interests abroad.
These transport workhorses are unlikely to arouse the same regional unease as the steady rollout of high performance fighters, long-range missiles or potent warships, but they are a crucial element of the People's Liberation Army's (PLA) three-decade military build-up, defence analysts say.
Over time, the air and sea support will give the world's second-largest navy greater geographical reach and will enhance the PLA's capacity to assist troops on distant battlefields, potentially including Taiwan if Beijing were to launch a military assault to take control of the self-governing island.
China's state-owned shipyards last year launched two 23,000-tonne type 903 replenishment ships, according to reports and photographs published on Chinese military affairs websites and blogs, with further orders in the pipeline.
Defence analysts say the state-of-the-art ships are undergoing sea trials and should be commissioned into the Chinese navy later this year.
China also confirmed last month that the PLA had conducted the first test flight of its Y-20 heavy lift aircraft from the Yanliang airbase near Xi'an in Shaanxi Province.
State-run television showed footage of the four-engine Y-20, the biggest aircraft built in China, taking off and landing. The Y-20, built by AVIC Xi'an Aircraft Industry (Group) Co Ltd, would have a 66-tonne payload, according to official media reports.
AMBITIOUS GLOBAL POWER
The impending delivery of these support ships and aircraft is further evidence China intends to become a more ambitious global military power in a decisive break with its traditional security priorities of expanding or defending its extensive land borders.
"They are beginning to develop their capacity for power projection, there is no question about that," says Li Nan, an expert on the Chinese military and a professor at the U.S. Naval War College in Newport, Rhode Island.
Steep increases in military outlays over three decades have allowed China to build an advanced navy that now ranks second to the United States fleet in terms of raw numbers.
The Chinese navy now has about 80 major surface warships including its first aircraft carrier, the Liaoning. It also deploys more than 50 submarines, about 50 landing ships and more than 80 missile attack boats, according to Pentagon estimates of PLA military strength.
However, construction of support and replenishment vessels in Chinese shipyards has lagged far behind the output of combatants.
China has only five major supply ships to support a fleet that is conducting increasingly intense patrolling and exercises around disputed territory in the South China Sea and East China Sea.
These vessels are also called upon to support the Chinese navy on a growing number of deployments far into the Indian and Pacific oceans.
By comparison, the U.S. navy has 34 big replenishment ships to support about 140 major surface warships, according to Pentagon figures.
The Chinese navy's extended missions include regular deployments of naval task forces to the Gulf of Aden and waters off the horn of Africa as part of United Nations authorized anti-piracy operations.
LOGISTICS CAPACITY STRETCHED
These operations have stretched the logistics capacity of the China's navy with its three most capable supply ships on almost permanent duty, according to details of the deployments announced by the Chinese military.
However, these deployments have provided an opportunity for the ships and crews to practise and refine the ongoing resupply of warships, highly skilled manoeuvres that are essential to keeping warships at sea for long periods, naval experts say.
China's defence ministry said that the frigate Mianyang, destroyer Harbin and the supply ship Weishanhu sailed on Feb. 16 from Qingdao on the 14th of these anti-piracy deployments.
While extra supply ships will extend the range and endurance of Chinese fleets, Beijing's strategic objectives still remain relatively limited outside the nearby seas where it is locked in territorial disputes with some of its neighbours.
"They are focusing on securing sea lanes, counter piracy and evacuating Chinese nationals in times of crisis," says Li.
China's expanding military transport capability is unlikely to have an immediate impact on its tense standoff with Japan over disputed islands in the East China Sea that are close to logistics bases on the Chinese mainland, naval analysts say.
"Support ships will not change the nature of operations in the East China Sea but will have an impact on the ability of the Chinese navy to conduct operations at sea, if the support ships are used to grow its professionalism and seamanship," says Alessio Patalano, a Japanese military expert at King's College in London.
LEANER, MOBILE FORCE
For China's top brass, the first test flight of the Y-20 was an important milestone as the PLA continues its transformation from a predominantly mass, ground army to a leaner, more mobile force.
"These aircraft are vital if you need to move a lot of people and a lot of equipment some place very, very fast," says Reuben Johnson, a Kiev-based military analyst and correspondent for Jane's Information Group, who has studied the Y-20 program.
Reports in the official Chinese media said the Y-20 could land and take off from restricted airstrips and had the capacity to carry most PLA combat and support vehicles.
Chinese military planners have drawn lessons from the importance of heavy-lift aircraft in recent U.S. and other Western military operations where the capacity to shift troops and supplies to distant battlefields or trouble spots has delivered an overwhelming advantage, military analysts say.
The U.S. military has a fleet of more than 300 heavy lift Galaxy and Globemaster aircraft in service along with more than 400 smaller-capacity transport aircraft.
Many of these aircraft can operate from short, uneven landing strips in remote and rugged terrain.
The PLA's air-lift capacity is much smaller. It currently operates about 20 Russian-built Il-76 transport aircraft. The Il-76 has a 50-tonne payload compared with the Globemaster's 77 tonnes and 118 tonnes for the Galaxy.
Additional Il-76 aircraft are reportedly on order from Russia but production bottlenecks are holding up deliveries, according to Russian military experts.
If China can introduce a sizeable fleet of Y-20 aircraft over the next decade, it will sharply enhance the PLA's capacity to land troops and equipment on distant battlefields.
Military experts say this capability would be particularly important in an invasion of Taiwan should Beijing decide to use force to establish control there.
Some analysts predict the Chinese military will order hundreds of Y-20s benefiting the group's listed unit, AVIC Aircraft Co Ltd, in coming decades if the aircraft can deliver acceptable performance.
They expect the PLA will also use the Y-20 as the basic airframe for its proposed fleet of in-flight refueling tankers and airborne early warning aircraft.