American and Philippine armed forces held their first ever combined airborne operations on September 22, a show of joint force that will have sent a strong signal to China amid rising tensions in the South China Sea.

The Cesar Basa Air Base, where the historic joint exercises were staged, has been partially opened to Americans under the recently implemented Enhanced Defense Cooperation Agreement (EDCA). Significantly, the facility is close to the Philippine-claimed Scarborough Shoal, which China seized and occupied after a weeks-long standoff with the Philippines in 2012.

Security analysts see China’s occupation of the feature as crucial to its eventual ability to establish an Aerial Defense Identification Zone (ADIZ) over the sea. The US and Philippines are long-time mutual defense treaty allies but Washington did not intervene in defense of the Philippines’ claim during the 2012 showdown.

That may change in any future China-Philippine confrontation. The joint air drill comes amid Manila’s rising anxiety over China’s harassment of Philippine supply lines in the Spratly islands and increased deployment of Chinese militia vessels to Philippine-claimed waters.

An estimated 500 soldiers of the Philippine Army’s First Scout Ranger Regiment and Special Forces Regiment (Airborne) and US Army’s 4th Brigade Combat Team (Airborne) participated in the drill, which was jointly overseen by Philippine and US commanding officers.

“This training will enhance our troops’ technical expertise in airborne operations, enabling our combat units to better respond to future contingency operations and other security challenges. Likewise, the combat interoperability with our US counterparts will also be strengthened,” said Philippine Lieutenant General Macairog Alberto.

A Philippine flag flutters as the nuclear-powered aircraft carrier USS Ronald Reagan (CVN-76) anchors off Manila Bay, June 26, 2018. Photo: AFP/ Ted Aljibe
A Philippine flag flutters as the nuclear-powered aircraft carrier USS Ronald Reagan (CVN-76) anchors off Manila Bay, June 26, 2018. Photo: AFP/ Ted Aljibe

The military drills, which saw troops jump from multiple US C-130 planes to simulate a rapid and massive deployment of troops to combat zones, focused on urban combat operations as well as maritime and territorial defense.

Airborne operations are specifically designed for resupply and operational support during extensive combat operations, as well as confronting conventional threats which are inaccessible to land and naval forces. US military officials have said US Air Force planes fly over the sea on a daily basis to protect freedom of overflight.

China did not immediately respond to the unprecedented airborne drills. In May, however, China deployed two naval vessels near the site of US-Philippine joint sea exercises which saw the US deploy a coast guard cutter to Philippine waters for the first time in seven years.

This week’s air drills coincided with the release of a new Philippine Department of National Defense (DND) report which accuses China of recently harassing a Philippine resupply mission at the Second Thomas Shoal.

Philippine officials have aired their diplomatic grievances over the perceived harassment of a feature where Manila stations troops. “Of course that’s objectionable. They are just ferrying supplies and food, why block them?” said presidential spokesman Salvador Panelo on September 23.

The disputed land feature, which lies within the Philippines’ exclusive economic zone (EEZ), has been under Manila’s de facto control since the late 1990s, when the Philippine Navy grounded a dilapidated vessel, the BRP Sierra Madre, in the area.

The contested shoal also lies just 37 kilometers from Mischief Reef, a low-tide elevation situated 217 kilometers from the Philippine island of Palawan.

China has recently transformed Mischief Reef into a massive military complex, with satellite imagery recently revealing the presence of anti-aircraft weapons and a missile defense system. The Philippines maintains a permanent Marines detachment at the Second Thomas Shoal, but China has nonetheless stepped up harassment of Manila’s recent resupply missions.

In 2014, during a months-long Chinese naval blockade of the feature, the Philippines relied on aerial resupply missions as well as American assistance provided by surveillance aircrafts to sustain its military presence at the shoal.

Map: Twitter

Despite improved bilateral relations under the Beijing-friendly Rodrigo Duterte administration, China has stepped up its harassment of Philippine-occupied features, coincident with a rising US commitment to ensure freedom of navigation in the sea.

The US has deployed ships at least 11 times to the South China Sea under US President Donald Trump’s administration. China insists the operations are illegal and violation of its sovereignty; Beijing’s so-called nine-dash line map claims nearly 90% of the sea.

According to the DND report submitted to the Philippine Congress during budget deliberations, a Chinese Coast Guard vessel blocked a Philippine resupply mission in the area in May 14. The Chinese ship reportedly moved as close as 1,460 meters to intimidate the incoming Philippine resupply vessels, the report said.

The armed forces’ Western Command, which is in charge of protecting the Philippines’ claims in the South China Sea, reported the presence of a Chinese Coast guard vessel close to the shoal in August.

The DND report also highlighted China’s growing deployment of maritime militia vessels to Philippine waters and occupied islands. In the first half of 2019, the military spotted 22 Chinese militia vessels within Philippine waters, an estimated 300 of which swarmed the Philippine-occupied Thitu Island in the Spratly islands.

The island’s Rancudo Airfield has a 1,300 meter unpaved airstrip that has seen both ends eroded into the sea. China’s pressure is viewed as an attempt to curb ongoing repairs to the runway, which were set to be completed by the end of 2019 but may not be finished because of the harassment.

The US had previously offered assistance to refurbish the strategic airstrip. The Philippine Navy has floated various strategic designs for the island, including the possible construction of a naval base for training its elite Special Warfare Group and Navy Seals.

The Philippine military claims that Chinese militia vessels serve multiple purposes, including surveillance and information- gathering on rival claimant states.

A satellite image of the Fiery Cross Reef in the South China Sea. Photo: Planet Labs

“There is high possibility that Beijing will continue the employment of these vessels, which could be used for asymmetric warfare of sea control and sea denial, such as swarming tactic and ramming of other claimants’ vessels in the area, enabling it to make advancements in the maritime region without causing tension in the area,” the DND report said.

The DND also warned about the “emerging trend” of Chinese warships being deployed to the Sulu-Celebes Sea area, particularly in Balabac Strait and Sibutu Passage in the southern portions of the Philippines, indicating a possible encirclement strategy.

Philippine Defense Secretary Delfin Lorenzana earlier this year complained about Chinese warships switching off their tracking devices while clandestinely moving through Philippine territorial seas.

The DND has likewise carped about being “persistently monitored” by Chinese warships and vessels in the Batanes Islands in the north, close to Taiwan, which China considers a renegade province and has promised to “reunify” with the mainland by 2020.

Whether the unprecedented US-Philippine joint air exercises will serve as a deterrent and alleviate Chinese pressure in the sea, however, is yet to be seen.