The Airspace Dispute Over Scarborough Shoal: How Far Will China’s Control Expand?
Executive Summary
The close encounter between a Chinese J-16 and a Philippine C-208 over Scarborough Shoal represents the latest phase in China’s gradual escalation of coercion, expanding its control from the sea surface to the airspace following its 2012 de facto maritime control and 2024 declaration of territorial sea baselines. Viewed alongside the expulsion of Philippine aircraft by armed JL-10 trainers in September and the standoff involving a Chinese research vessel near the Batanes Islands, China is using military assets to block airspace—a bypass route that its coast guard cannot physically obstruct—while expanding its operational footprint beyond southern strongholds to northern waters near the Taiwan Strait. As the level of response escalates from coast guard-centered operations to the full exposure of military assets, the threshold of escalation is shifting to aerial encounters, where the buffer zone is far narrower than at sea. Despite the legal superiority of the Hague ruling, the persistent lack of enforcement, combined with the stagnation of negotiations on the ASEAN Code of Conduct, suggests that gray-zone tensions will remain structurally entrenched for the foreseeable future. Businesses exposed to regional maritime and air transit, as well as supply chains, should reassess their risk management frameworks under the assumption that sudden encounters could become normalized.
I. Situation Analysis
A New Front Opens in the Airspace Over the South China Sea
On October 3, a Philippine military C-208 aircraft had a close encounter with a Chinese J-16 fighter jet in the airspace near Bajo de Masinloc (Scarborough Shoal). The Philippine military described this as a "close encounter" and stated it was a dangerous maneuver that threatened aviation safety [4]. The PLA Southern Theater Command characterized the same incident in completely opposite terms, claiming that the Philippine aircraft "illegally entered the airspace over Huangyan Dao without the approval of the Chinese government" and that its forces warned and expelled it "in accordance with laws and regulations" [7]. The stark contradiction between the two sides' accounts of a single incident in the same airspace demonstrates that this was not a simple accidental encounter, but rather an extension of accumulated structural conflict.
From 2012 to the Airspace: Gradually Tightening the Line of Control
Bajo de Masinloc is a coral reef formation located 240 kilometers west of Luzon Island, within the Philippine Exclusive Economic Zone (EEZ) [4]. It is hundreds of kilometers away from the Chinese mainland. China has maintained de facto control over the area since a standoff between the two countries' vessels in 2012 [4]. In 2016, the Permanent Court of Arbitration (PCA) in The Hague ruled that China's "nine-dash line" claim had no legal basis, but Beijing refused to recognize the ruling [1]. In September of this year, a JL-10 training aircraft equipped with PL-5 missiles was deployed to expel three Philippine light aircraft over Scarborough Shoal. The recent J-16 encounter is situated within this broader trend of Beijing incrementally expanding its domain of control—from de facto control on the water's surface and the declaration of territorial sea baselines to airspace control.
China's state-run Global Times describes these movements as "regular combat readiness patrols to safeguard sovereignty and regional stability" [14]. Reports that the coast guard and navy conducted joint patrols around Huangyan Dao during the same week support this framing [14]. From Beijing's perspective, the message is that the J-16 encounter was not an isolated incident but rather an extension of regularized "law enforcement" activities.
The Front Line Now Reaches the Batanes
Tensions are not confined to Scarborough Shoal. In the waters near the Batanes, the northernmost province of the Philippines, the Chinese research vessel Jia He Ke 7 stayed for four days, leading to a standoff with the Philippine Coast Guard. The Philippine Coast Guard deployed its largest vessels and aircraft to drive the ship away, and the government in Manila officially rejected China's claim to "sovereign rights" jurisdiction over those waters [9]. This indicates that, in addition to the southern front centered on Scarborough Shoal, China's operational radius is expanding to northern waters close to the Taiwan Strait.
This trend was also detected within US diplomatic circles during the UN General Assembly. In a panel discussion at the Brookings Institution, it was pointed out that "just days after Xi Jinping's visit to the US, the Southern Theater Command announced military exercises around Scarborough Shoal," leading to the assessment that "as long as Washington agrees to this concept, Beijing feels it is pushing on an open door" [5]. At a Council on Foreign Relations (CFR) event, a Philippine representative described trade relations with China as "robust" but noted that "on the security front, maritime encounters continue" [2]. At the same event, it was confirmed that ASEAN's efforts to draft a Code of Conduct (COC) for the South China Sea remain stalled on key issues, such as the "definition of self-restraint" [2].
Three Perspectives, Three Calculations
The PLA Southern Theater Command consistently frames this incident as a matter of law enforcement. This approach involves claiming airspace violations and emphasizing the procedural legitimacy of issuing warnings and expelling the aircraft [7]. The patrol pattern of simultaneously deploying both the coast guard and the navy aligns with an asymmetric response logic: countering the opponent's low-cost reconnaissance assets with low-cost deterrent measures.
The Philippine military and coast guard repeatedly use the phrase "pattern of dangerous behavior" [4]. By highlighting that these are not isolated incidents but rather a cumulative pattern of behavior, they appear to be seeking international support and backing within ASEAN. As this year's ASEAN chair, the Philippines seeks to maximize its voice within regional multilateral frameworks. However, it faces the paradox of being unable to elicit a collective response on South China Sea issues due to differing positions among member states.
Malaysia emerges as a third stakeholder in this dynamic. Due to the geographical proximity of the US-supported Philippine base on Balabac Island to the state of Sabah, Kuala Lumpur is concerned about the potential "spillover" of regional conflict. Malaysian Defense Minister Khaled Nordin specifically mentioned Sabah when discussing the need to strengthen defense capabilities as a preventive measure [10]. This indicates a clear divergence in threat perception within ASEAN between claimant and non-claimant states.
Why Common Ground Remains Elusive
The fundamental gap between the two sides' claims lies in the legal status of the airspace itself. China defines the airspace over Huangyan Dao as an extension of its territory and considers any entry without prior approval to be illegal [7]. The Philippines, operating on the premise that the waters lie within its EEZ, characterizes its aircraft's activities as routine reconnaissance [4]. Although the 2016 Hague ruling denied that features in the Spratly Islands generate entitlement to an EEZ or continental shelf, the lack of enforcement mechanisms means this ruling has failed to bridge the gap.
The fact that negotiations on the ASEAN Code of Conduct are stalled on fundamental issues, such as the definition of "self-restraint" [2], also highlights this structural vacuum. In the absence of established norms, physical dominance on the ground dictates the de facto rules. This situation serves as the backdrop for the recurrence of gray-zone incidents, including the recent aerial standoff.
II. In-Depth Analysis
The Calculations Behind the Airspace Dispute: Why the Skies, and Why Now?
Viewed in isolation, the encounter between the J-16 and the C-208 over Bajo de Masinloc could be interpreted as an accidental close flight. However, when this encounter is placed alongside the expulsion of Philippine aircraft by armed JL-10 trainers in September and the standoff involving the research vessel near the Batanes, a different picture emerges [7][9]. The common thread among these three incidents is that China is simultaneously expanding its physical control from the sea surface to the airspace, and from southern strongholds to northern waters. It is therefore necessary to examine why the airspace, rather than the sea, has emerged as a key front line, and why this is happening at this particular juncture.
Airspace: Chosen Because the Coast Guard Cannot Block It
Maritime control around Scarborough Shoal has been maintained by the Chinese Coast Guard through continuous deployment since 2012 [3]. Access for Philippine fishers and vessels is physically blocked on-site. The issue is that this control is restricted to the "sea surface." Philippine Air Force and Coast Guard aircraft have been able to bypass the coast guard's blockade by conducting reconnaissance missions in the airspace above. The deployment of the JL-10 in September and the J-16 encounter in October can be interpreted as countermeasures designed to close off this bypass route.
A previous EAI report characterized this transition as "the latest phase in a gradual escalation of coercion, moving from de facto control on the ground in 2012 and the declaration of territorial sea baselines in 2024 to airspace control" [3]. The choice of assets is particularly noteworthy. Deploying the JL-10 training aircraft, which is suited for countering slow-moving turboprops, rather than a fighter jet, has been evaluated as a "low-cost, sustainable gray-zone tactic" [3]. The subsequent J-16 encounter, which involved mobilizing actual fighter assets for airspace control, should be viewed not merely as a diversification of means, but as an escalation of means.
The Pattern Observed at Second Thomas Shoal, Replicated in the Skies
The logic behind this escalation was already demonstrated during the Second Thomas Shoal incident last month. During the interception of a resupply mission on September 24, China raised its response level from unilateral coast guard action to "simultaneous intervention by the PLA Navy" [8]. An EAI analysis identified this at the time as a case of "shifting from operations centered on the coast guard and maritime militia to a stage of fully exposing naval assets" [8]. The appearance of the J-16 in the airspace is evidence that this shift to exposing military assets is not confined to the sea. In domains where the coast guard cannot easily operate—namely, aircraft-to-aircraft encounters—military assets are deployed on the front line from the outset.
This pattern is significant because it shifts the threshold of escalation. The physical consequences of an accidental collision differ greatly between water cannon standoffs between coast guard vessels and close-range maneuvers by fighter jets. At sea, there is some room for a buffer, as seen in incidents where water cannons were fired at Chinese fishing vessels near the Taiwan Strait [16]. In the air, that buffer is far narrower. This explains why the Philippine military publicized the incident, emphasizing the "threat to aviation safety."
The Asymmetry Created by the Hague Ruling, and What It Cannot Change
The 2016 Permanent Court of Arbitration ruling rejected both China's nine-dash line claim and the EEZ entitlements of features in the Spratly Islands [1][3]. From a purely legal standpoint, the Philippines holds a clear advantage. However, the ruling lacks enforcement power. After declaring the ruling "null and void and having no binding force" [6], China responded by building up its physical presence on the ground. This disconnect between legal legitimacy and de facto control has persisted for over a decade.
This asymmetry is most clearly demonstrated by the designation of Scarborough Shoal as a "nature reserve." By controlling access under the guise of environmental management rather than directly asserting sovereignty claims, Beijing bypasses accusations of violating international law while achieving the practical effect of exclusion. This strategy effectively shifts the arena of legal dispute from sovereignty to administrative management. Airspace control follows a similar logic. Beijing characterized the recent encounter not as a territorial dispute, but as domestic law enforcement "in accordance with laws and regulations" [7]. Refusing to label the dispute as such is itself a key part of the strategy.
Why ASEAN Fails to Speak with One Voice
The difficulty in formulating a unified ASEAN response stems not simply from a lack of solidarity, but from the divergent interest structures of its member states. Malaysia, noting the presence of a US-supported Philippine base on Balabac Island near Sabah, is concerned that regional conflict could spill over into its own territory [10]. This context explains why the Malaysian Defense Minister publicly raised the possibility of "unforeseen incidents" spreading and announced plans to strengthen defense capabilities [10]. In other words, Malaysia's primary concern is not the merits of the South China Sea territorial disputes, but rather preventing any negative repercussions on its own security.
At the same time, as this year's ASEAN chair, the Philippines must respond in its official capacity to other regional issues, such as the airstrikes in Myanmar's Rakhine State, in addition to the South China Sea issue in which it is directly involved [11][12][13]. This dual status as both a disputant and the chair constrains rather than expands the Philippines' room for maneuver. There is a perception within the region that pushing the South China Sea issue onto the ASEAN agenda conflicts with the role of a neutral chair. These differing calculations among member states explain why negotiations on the Code of Conduct remain deadlocked over basic issues like the "definition of self-restraint" [2].
What the US 'Open Door' Remark Indicates
The assessment from the Brookings Institution discussion that "Beijing feels it is pushing on an open door" [5] provides a crucial clue for interpreting the recent airspace standoff. The timing of the Southern Theater Command's announcement of military exercises around Scarborough Shoal—immediately following Xi Jinping's visit to the US—demonstrates that diplomatic schedules at the leader level and military actions on the ground operate on separate tracks. As Washington repeatedly responds to airspace and maritime encounters only at the level of official statements, observers point out that Beijing may interpret this pattern of response not as a constraint, but as latitude for action.
The remarks by the Philippine representative at the CFR event, describing trade relations with China as "robust" [2], illustrate the same structure from a different angle. This dual-track dynamic—where airspace standoffs continue on the security front while economic relations are maintained separately—functions as a condition that prevents the South China Sea dispute from escalating into a full-scale war while simultaneously prolonging it.
Variables Shaping the Next Phase
Whether this situation settles into a low-intensity airspace standoff or escalates further depends on several variables. First, whether China's shift in deployed assets from the JL-10 training aircraft to the J-16 fighter jet is a one-off response or represents a new baseline for airspace control. Second, whether the front lines that have expanded beyond Scarborough Shoal, such as the Batanes waters, will also lead to aerial standoffs in the north. Unlike previous standoffs involving research vessels that were limited to coast guard encounters [9], the mobilization of aerial assets in this area would indicate that the airspace control strategy is not confined to Huangyan Dao.
Third, whether the pattern observed in the Second Thomas Shoal case—where "verbal understandings are reinterpreted based on physical dominance on the ground" [8]—will also apply to the airspace. If tacit practices or signaling procedures regarding aviation safety exist, those procedures, like the maritime understandings, are highly likely to remain undocumented and subject to dominance on the ground. In this scenario, the risk of accidental collision in the airspace would rise much more steeply than at sea.
References
[1] [Channel News Asia] China, Philippines trade accusations over South China Sea aircraft encounter
[2] [Council on Foreign Relations (CFR)] World Leaders at CFR: Highlights From UNGA 2026
[4] [Rappler] PH military says ‘close encounter’ with China fighter plane near Bajo de Masinloc
[5] [Brookings Institution] What’s next for US-China relations after Xi Jinping’s state visit?
[11] [Daily Sabah] Philippines urges ASEAN talks after 50 killed in Myanmar airstrike
[12] [Bangkok Post] Philippines voices concern over Myanmar airstrike deaths
[13] [Al-Monitor] Philippines voices concern over Myanmar airstrike deaths, injuries
[15] [Channel News Asia] Philippines voices concern over Myanmar airstrike deaths, injuries
[17] [DW (Deutsche Welle)] What China's Laos foothold means for the region
[18] [Bangkok Post] China widens military footprint with Laos air base
[21] [Al Jazeera] Taiwan Coast Guard confronts Chinese fishing boats in Dongsha waters
[25] [Rappler] SC junks petitions vs conviction voting threshold | The wRap
*This text is an AI translation of an original written in Korean. Some translations or nuances may be inaccurate.
This report is an in-depth analysis planned by an EAI researcher, grounded in sophisticated AI-assisted research, and finalized by the EAI researcher.
How can I help you?