Air Defense Identification Zone (Taiwan)

The Taiwan Air Defense Identification Zone is an air defense identification zone covering Taiwan and its surrounds. It includes a large portion of the Chinese mainland. A theoretical "median line" was defined in 1955 one year after the zone was established. The ADIZ includes international airspace that countries can arbitrarily monitor. In recent years, it has seen an increased number of sorties flown by People's Liberation Army (PLA) aircraft.^[1][2][3]

The Taiwan Air Defense Identification Zone as shown in orange boundaries in the lower left of the diagram

Background

The Taiwan ADIZ covers most of the Taiwan Strait, parts of Fujian, Zhejiang, and Jiangxi, and part of the East China Sea. It was designed and created by the United States Armed Forces (USAF) in 1954^[4]: 42 and the basis of Taipei Flight Information Region.^[5][6]: 15 The zone is monitored by PAVE PAWS radar located near Hsinchu and operated with help from US advisors.^[7]

Median line

A theoretical line was defined in 1955 down the middle of the strait, supposedly named after USAF General Benjamin O. Davis Jr.^{[8][9][4]: 42} Aircraft from Taiwan flew combat missions on the other side until they lost control of mainland airspace to the PLAAF after the Second Taiwan Strait Crisis. ROCAF U-2 planes continued to fly over the mainland until 1968.^{[4]: 45–58} The line was avoided by the PRC until 1999 when groups of PLAAF aircraft crossed over in response to "state-to-state" comments made by Lee Teng-hui. Beijing has never recognized the line.^[1][3] The PRC has flown an increased number of sorties across the median line,^[10][11] although it tries not to do so when relations with Taiwan are good.^[12]

Recent PLA activities

Around 9% of Taiwan's national defence budget in 2020 reportedly goes into the response to Chinese sorties, which usually involve flights inside the southwest part of the ADIZ, crossing of the median, or circumnavigation.^[13] Beginning in September 2020, the Ministry of National Defense of Taiwan (MND) began reporting PLA sorties in the ADIZ that flew beyond mainland territorial airspace.^[1]

During 2021, 972 such sorties were flown by the PLA. This increased to 1,727 in 2022,^[14] with the most on any single day being on 5 August after the 2022 visit by Nancy Pelosi to Taiwan, when 49 sorties were flown.^[1]

On 26 December 2022, a record 71 PLA aircraft entered the ADIZ, including 43 that crossed the median line.^[15]

After the United States approved a weapons sale to Taiwan in 2023, the MND reported thirteen PLA aircraft that crossed the median line on 25 and 26 May, including two Xian H-6 bombers.^[16][17]

References

1. "2022 in ADIZ Violations: China Dials Up the Pressure on Taiwan". ChinaPower Project. Retrieved 7 May 2023.
2. "The skies over the South China Sea". Reuters. 19 October 2021.
3. Campbell, Brian E. (July–August 2022). "Record-Setting Incursions into Taiwan's Air Defense Identification Zone: The People's Republic of China's Psychological Operations Designed to Erode US Support for Taiwan" (PDF). Journal of Indo-Pacific Affairs.
4. Allen, Kenneth; Garafola, Cristina. 70 Years of PLA Air Force. Montgomery, Alabama: China Aerospace Studies Institute, Air University. ISBN 9798724860888.
5. "Chinese aircraft enters Taiwan's ADIZ for 7th time in 8 days | Taiwan News | 2020-09-25 10:59:00". 25 September 2020.
6. 許書耕、賴威伸、胡智超、李宇欣、陳春益、林東盈、李威勳、陳佑麟、袁永偉、盧立昕 (2018). "第三章 我國空域與桃園國際機場空側". 構建空域模擬模式之研究 : 以臺北終端管制區域為例 (in Traditional Chinese). 臺北市: 交通部運輸研究所. ISBN 9789860557862.
7. Chen, Kelvin (14 October 2020). "Taiwan Air Force Command confirms US presence at Leshan radar station | Taiwan News | 2020-10-14 11:35:00". Taiwan News.
8. "Navigating the Black Ditch: Risks in the Taiwan Strait". Center for International Maritime Security. 25 December 2014.
9. "General Benjamin Oliver Davis Jr". United States Air Force.
10. Trent, Mercedes (2020). "Over the Line: The Implications of China's ADIZ Intrusions in Northeast Asia" (PDF). Federation of American Scientists. p. 23. (PDF) from the original on 3 October 2022.
11. Cole, J. Michael (22 September 2020). "China Ends 'Median Line' in the Taiwan Strait: The Start of a Crisis?". The National Interest.
12. "What is the Median Line Between China and Taiwan?". VOA. 28 October 2020.
13. Shattuck, Thomas J. (7 April 2021). "Assessing the Patterns of PLA Air Incursions into Taiwan's ADIZ - Foreign Policy Research Institute". Global Taiwan Brief. 6 (7).
14. "China's warplane incursions into Taiwan air defence zone doubled in 2022". The Guardian. Agence France-Presse. 2 January 2023. ISSN 0261-3077. Retrieved 7 May 2023.
15. Lee, Yimou (26 December 2022). "Taiwan reports China's largest incursion yet to air defence zone". Reuters. Retrieved 7 May 2023.
16. "Taiwan sees second Chinese air incursion as US agrees arms sale". Aljazeera. 2 March 2023. Retrieved 9 May 2023.
17. "13 Chinese aircraft breach Taiwan's ADIZ: Defense Ministry - Focus Taiwan". Focus Taiwan - CNA English News. Retrieved 31 May 2023.