Note: Information in this article is current as of September 1, 2024.
For approximately four years, the People’s Liberation Army (PLA) of the People’s Republic of China (PRC) has conducted regular operations within Taiwan’s air defense identification zone (ADIZ). Throughout this period, these operations have shifted in geographic focus, and have evolved to elevate the coercive pressure and level of threat against Taipei. Originally, these incursions were primarily limited to the southwestern ADIZ region in the South China Sea (near Taiwan’s Pratas/Dongsha island), and large-scale drills were tied to high-profile political events favoring Taiwan. Then, after the August 2022 visit to Taiwan by then-US House Speaker Nancy Pelosi, the ADIZ operations shifted from the South China Sea to the Taiwan Strait as the primary locus of activity. With its incursions over the last two years, the PRC has essentially erased the median line of the Taiwan Strait.
In 2024, the dynamics have shifted again, with the election and elevation of Lai Ching-te (賴清德) to the presidency in Taiwan. A notable development in this space was the introduction of balloons flying over and around Taiwan in the lead-up to the January 2024 election. In December 2023, 7 balloons were tracked in the ADIZ, but that figure increased in January and February (with 57 and 26, respectively). However, balloon tracking—while an interesting development—is not the most important issue for Taiwan’s ADIZ in 2024 and in the Lai era beyond.
Now, flight activity to the east of Taiwan has become a more regular feature of the military status quo and ADIZ operations more generally. There are two broad patterns for such ADIZ activity: typical operations off Taiwan’s east coast, and circumnavigation flights that eclipse both the northern and southern points of the island. This eastern activity is notable because it demonstrates a shift from training and navigation operations to testing likely combat concepts in the event of a blockade or military invasion of Taiwan. Expanding the “eastern front” shows an increase in sophistication from pilots, who are required to fly longer distances—including longer distances over water, further away from the PRC coastline—and possibly through the ADIZs of Japan or the Philippines.
Such missions point to the next step in the PRC’s ADIZ operations: a move from signaling discontent and placing coercive pressure on Taiwan, to beginning to prepare pilots for an eventual contingency that requires a new set of competencies.
A Look at the Numbers
The PLA’s aviation presence east of Taiwan can be divided into two categories: rotary-wing aircraft (helicopters) launched from PLA Navy (PLAN) vessels operating in the Western Pacific, and fixed-wing aircraft. While the near-constant presence of the PLAN east of Taiwan is troubling, an increasing number of fixed-wing aircraft launched from the PRC have conducted operations east of Taiwan since 2020, when Taiwan’s Ministry of National Defense (MND, 國防部) began releasing reports on PLA and PLAN activity within the ADIZ. PRC military aircraft now regularly fly on both sides of the island, sandwiching Taiwan between military forces.
While Beijing is unlikely to cease its operations within the Taiwan Strait proper, the expansion of activity to the east of Taiwan presents a troubling development that Taiwan’s military must counter.
In 2021, 59 fixed-wing PLA aircraft were tracked operating east of Taiwan, with eight instances of multi-aircraft flights. On only two days in 2021, 10 or more aircraft flew in this area on the same day or during the same operation. In 2022, that number decreased, with only 50 aircraft being tracked, with eight instances of multi-aircraft flights. On only one day did 10 or more aircraft fly to Taiwan’s east on the same day or during the same operation. Interestingly, Taiwan’s MND did not report any activity to the country’s east during the August 2022 PLA joint exercises in response to Pelosi’s Taiwan visit (see discussions here and here). During those exercises, 446 PLA aircraft operated inside the ADIZ, but Taiwan’s MND did not track aircraft east of the island even though the PLA and PLAN conducted operations off Taiwan’s eastern shores during this time. [1]
In 2023, however, the figure nearly tripled, with 149 fixed-wing aircraft tracked east of Taiwan, including 18 instances of multi-aircraft flights. This time, Taiwan’s MND reported activity during the PLA exercise Joint Sword, conducted in response to the California-based meeting between then-US House Speaker Kevin McCarthy and then-Taiwan President Tsai Ing-wen. On April 10, the MND reported 15 J-15 aircraft flying to Taiwan’s east. On that day, 31 aircraft crossed the median line of the Taiwan Strait, for a total of 54 reported aircraft within the ADIZ on that date. During Joint Sword, 19 aircraft were tracked east of Taiwan over two days: all of them J-15s launched from the Shandong aircraft carrier group. In total for 2023, there were five dates on which the MND tracked more than 10 aircraft to Taiwan’s east.
Between 2021 and 2023, the fighter aircraft most frequently operated to Taiwan’s east were J-11s, J-15, and J-16s, alongside H-6 bomber aircraft. The most complex incursions—based on the mix of aircraft—occurred on December 21, 2022, and June 8, 2023. In the December 2022 incursion, H-6 bombers and J-16 fighter jets flew in tandem with a KJ-500 airborne early warning and control aircraft and Y-20 refueling aircraft. In the June 2023 mission, H-6 bombers, with J-11s and J-16s, flew with WZ-7 uncrewed aerial vehicles (UAV), Y-9 electronic intelligence aircraft, and Y-20U aerial refueling aircraft. The presence of the Y-20U in these types of operations suggests that at least one of the aircraft on the mission almost certainly refueled mid-flight. These types of mission makeups also occurred at smaller scale during this timeframe.
In 2024 (up to August 31st), the numbers point to Taiwan’s eastern flank being a new area for focus by the PLA and PLAN. Overall, 140 fixed-wing aircraft have been tracked around Taiwan’s east, including 18 instances of multi-aircraft flights. Notably, all of the days in which more than 10 aircraft were tracked to Taiwan’s east (to date, four in total) occurred after the inauguration of Lai. Two of those dates include the Joint Sword 2024A exercise that occurred in direct response to Lai’s inauguration in May 2024. Given the January 2024 changes in how Taiwan’s MND reports ADIZ activity, it is unknown what specific types of aircraft have flown to Taiwan’s east since then. While unknown types of UAVs have been tracked, any further details are unavailable as to what aircraft are involved in these activities. This point demonstrates one of the multiple major downsides to the MND’s January 2024 changes to ADIZ reports.
In addition to the increase in instances where multiple fixed-wing aircraft were tracked east of Taiwan on the same day, the average number of aircraft tracked in those instances has also increased. In 2021, the average number of aircraft tracked was 7; in 2022, it was 4.75; in 2023, it was 7.44; and 2024, it is 7.78 thus far. These averages demonstrate a slow, but steady, increase in the PLA and PLAN’s aerial operations to Taiwan’s east.
Why Does This Matter?
These overall figures for aviation activity to Taiwan’s east are small compared to the overall figures for PLA and PLAN ADIZ activity, but the implications of this increase are important. During this same timeframe, activity over the median line of the Taiwan Strait has skyrocketed. In 2020, 22 aircraft were tracked crossing the median line (with no such activity in 2021). The year 2022 marked a stark shift in the PRC’s focus in the ADIZ: with 565 aircraft tracked crossing the median line, followed by 703 in 2023 and 805 in 2024 (to date). Overall, ADIZ activity has also trended upward: between 381-390 sorties in 2020; 972 in 2021; 1,738 in 2022; 1,703 in 2023; and 1,905 in 2024 (to date). Compared to the activity in other areas, the PLA’s presence east of Taiwan appears negligible.
However, the trends for eastern side flight activity are concerning because they are not occurring in a vacuum. Such flights are occurring in tandem with other aerial or naval activity around Taiwan, which increases the burden on Taiwan’s already limited resources. If the trends in the east continue, Taipei will be forced to make difficult decisions on how to respond to this activity, and will need to prioritize some geographic areas over others. Do you focus on the Taiwan Strait because there is more activity there, and it is considered a geopolitical hotspot? Does Taipei cede its east because it’s theoretically more difficult for the PLA to get to, and because of the overall lower level of activity?
We know from past policy changes by Taipei that the ADIZ incursions are having an immense impact on the MND and Taiwan’s military. In 2021, Taipei stopped the policy of intercepting every single sortie because it was breaking the MND’s budget, and began tracking aircraft with ground-based missiles instead. In 2020, the MND spent nearly nine percent of its total budget on intercepting, monitoring, and detecting ADIZ incursions. What happens when the activity to Taiwan’s east continues to increase to the level of activity in the southwestern ADIZ in late 2020 and early 2021, which forced those policy changes? The PRC is increasingly surrounding Taiwan at all sides in the air (and at sea), so this developing trend in the Western Pacific is important to analyze at this somewhat early stage—before it becomes the next Taiwan Strait in terms of regular activity.
The main point: Since Taiwan’s MND began tracking and reporting on PRC military aircraft within its air defense identification zone in September 2020, three trends can be identified: (1) the number of PLA aircraft operating east of Taiwan is increasing; (2) the number of multi-aircraft flights east of Taiwan is increasing; and (3) the number of aircraft taking part in multi-aircraft flights east of Taiwan is increasing.
[1] Figures on PLA flight activity are drawn from the “Taiwan ADIZ Violations Database” maintained by PLATracker: https://docs.google.com/spreadsheets/d/1qbfYF0VgDBJoFZN5elpZwNTiKZ4nvCUcs5a7oYwm52g/edit?gid=2051027998#gid=2051027998.
