Republic of China's defense minister, Yen Teh-fa, the People's Republic of China sends about 2,000 bomber patrols per year to the Taiwan Strait separating Taiwan and the Chinese mainland These patrols significantly increased since 2019 and now routinely crosses the median line in Taiwan's air defense zones, causing the scrambling of fighters. These air scrambles put heavy strain on ROC airforce aircraft and cost around 9% of Taiwan's national defense budget or about T$25.5 billion ($886.49 million) in 2020 alone. ROCAF strategy until some years ago was to use IDF fighters for low altitude interception and ground attack, F-16s for mid-altitude interception and ground attack and Mirage 2000-5s for high altitude interception. Taiwan had to upgrade F-5 fighters due to issues in buying modern fighters. In proposed defense policy, the ROCAF seeks to deny the PLAAF air operations around Taiwan by deploying integrated air defenses, including Patriot PAC-3 batteries and Tian Kung-2 surface to air missiles assigned to defend air bases, and smaller mobile air defense systems to prevent the PLA from providing air support to invading forces. Organization Like most of the other branches of the ROC armed forces, much of the ROCAF's structure and organization is patterned after the United States Air Force. Like the USAF, the ROCAF used to have a wing → group → squadron structure. After November 2004, tactical fighter wing switch to wing → Tactical Fighter Group, with some fighter squadrons stood down, with each tactical fighter group, still pretty much the same size as a squadron, now commanded by a full colonel. The main operational units in Taiwan Air Force include: 6 tactical combat aircraft wings. 1 transport and antisubmarine wing. 1 tactical control wing. 1 communication and ATC wing. 1 weather forecasting wing. 1 Air Defense and Artillery command, comprising 5 Brigade, 16 air defense artillery battalions. Republic of China Air Force Command Headquarters Air Force GHQ is subordinate to the Chief of the General Staff (military), the Minister of National Defense (civilian) and the President. Internal Units: Personnel, Combat Readiness and Training, Logistics, Planning, Communications, Electronics & Information, General Affairs, Comptroller, Inspector General, Political Warfare. Air Force Combatant Command Weather Wing: Tamsui, New Taipei City Communications, Air Traffic Control & Information Wing : Taipei City Air Tactical Control Wing Ground fixed and mobile long-range air search radar sites, consist of various TPS-117, TPS-75V, FPS-117, GE-592 and HADR radars, plus 1 PAVE