In early September 2015, AMTI released images showing that China had effectively completed construction of its first Spratly Islands airstrip on Fiery Cross Reef, was continuing work on its second at Subi Reef, and was preparing to begin work on a third at Mischief Reef. Four months later, China has not only landed three civilian test flights on Fiery Cross, but is progressing even faster than expected with its work at Subi and especially Mischief. Construction of the Fiery Cross airstrip took at least seven months from the start of grading, which was visible by February 2015. Work at Subi, where grading began in June or July, seems to be proceeding slightly quicker. And at Mischief, where grading began in September or October, construction is already approaching completion just three to four months later. Meanwhile China is rapidly building out other facilities on both Mischief and Subi.
Mischief Reef sits just 21 nautical miles from the BRP Sierra Madre, which was deliberately grounded by the Philippines at Second Thomas Shoal in 1999 and is home to a contingent of Philippine marines. China has maintained a constant coast guard presence around Second Thomas since 2013 and attempted to prevent resupply of the Sierra Madre in March 2014. Mischief is also about 60 nautical miles from Reed Bank, where the Philippines hopes to drill for natural case deposits over China’s objections. This strategic location combined with its size(China has reclaimed twice as much land at Mischief Reef as it did at Fiery Cross and about 50 percent more than at Subi) makes developments at Mischief of particular concern the Philippines.
The work on the runway at Mischief Reef is progressing considerably faster than it had at Fiery Cross or Subi. Preparatory work had started by the start of September, but the runway itself was not visible. A fully formed and compacted sand runway could be seen by October 19, and by December 5 the runway and apron had been covered with gravel and about 500 feet of concrete. As of January 8, concrete covered most of the runway, which appears to be nearing completion.
Subi is at the northern end of the Spratlys, just 13 nautical miles from the main Philippine-occupied feature Thitu Island, which boasts a small civilian population. Subi is also less than 40 nautical miles from Taiwan’s only holding on Itu Aba, which is the largest natural feature in the Spratlys. Subi was the target of a much-anticipated freedom of navigation operation (which also passed near four other features not occupied by China) on October 26.
Construction of the airstrip at Subi Reef is nearing completion after six or seven months of work. By November 19, the base layer of sand for the runway had been compacted and channels dug for concrete guides. By December 21, a base layer of gravel had been laid down across most of the runway and some concrete strips were visible on its northern end (lower portion of photo below). As of January 8, the southern end of the runway (not pictured) had been paved with concrete as had most of the runway and apron at the northern end, while the gravel base had been completed and concrete strips were visible in the central portion.
The Financial Times has further coverage of these developments here.