According to foreign media reports, France recently signed a letter of intent with Sweden to order two "Global Eye" early warning aircraft from the country's Saab company, replacing the old E-3F early warning aircraft, and retaining the option to order two additional aircraft. Coincidentally, Canada and the United States have also shown new trends in the procurement of early warning aircraft, which has attracted widespread attention from the outside world. The "Global Eye" early warning aircraft is based on the "Global" 6000 business jet developed by Bombardier in Canada, equipped with one "Aleyan" early warning radar developed by Saab, and equipped with Leonardo's "Wave Flower" 7500E sea surveillance radar and multiple types of sensors. This early warning aircraft has a smaller body than the E-3F early warning aircraft, but its endurance time is basically the same, and it has advantages in maritime surveillance capabilities and maintenance costs. The "Ailiyan" early warning radar it is equipped with is an active phased array radar, weighing about 1 ton, with a maximum detection range of 550 kilometers. It can detect, track, and monitor various air and water targets, and its performance is better than the pulse Doppler radar of the E-3F early warning aircraft. Due to the lack of shipborne capability of the "Global Eye" early warning aircraft, in addition to purchasing this type of early warning aircraft, the French Navy also plans to purchase three E-2D early warning aircraft from the United States to replace the E-2C shipborne early warning aircraft on the Charles de Gaulle aircraft carrier. Saab is still promoting the "Global Eye" early warning aircraft to Canada. In the company's view, the "Global Eye" early warning aircraft platform using the Canadian "Global" 6000 business jet can reduce procurement and maintenance costs in Canada and promote the development of the Canadian aviation industry. In addition, the early warning aircraft is equipped with the "Wave Flower" 7500E maritime surveillance radar, which can detect small motorboats and submarine periscopes on the sea surface from a distance. This is of great significance for Canada seeking to expand its military presence in the Arctic region. According to reports, the competitor of the "Global Eye" early warning aircraft in Canada is Boeing's E-7 early warning aircraft. The E-7 early warning aircraft and the P-8 anti submarine patrol aircraft that Canada is about to receive are both improved based on the Boeing 737 aircraft platform and have advantages in maintenance and other aspects. However, the development prospects of the E-7 early warning aircraft have not been optimistic recently. The US Air Force originally planned to replace the old E-3 early warning aircraft with the E-7 early warning aircraft, but according to foreign media reports, the US Department of Defense and Air Force are considering canceling the E-7 early warning aircraft procurement plan and instead adopting the E-2D early warning aircraft used by the US Navy. Analysts say that the US Air Force's consideration may be due to the fact that the E-2D early warning aircraft is cheaper, more advanced in performance, and its takeoff and landing characteristics are more in line with the US Air Force's "agile combat deployment" concept compared to the E-7 early warning aircraft. However, analysts believe that the E-2D early warning aircraft has a series of applicability issues for the US Air Force. Firstly, the E-2D early warning aircraft can only carry 5 command personnel, which limits its command capability compared to the E-7 early warning aircraft. Secondly, the range, flight speed, and altitude of the E-2D early warning aircraft are not as good as those of the E-7 early warning aircraft, especially at lower flight altitudes, which limits its radar detection range. Again, the E-2D early warning aircraft uses the hose refueling method commonly used by the US Navy, while the US Air Force uses the hard hose refueling method. Although some KC-135R refueling aircraft of the US Air Force are equipped with hose refueling pods and tapered hoses at the end of the refueling hard tubes, it will affect refueling for other aircraft models. Meanwhile, the E-2D early warning aircraft powered by turboprop engines flies slower than the KC-135R tanker powered by jet engines, which affects the organization and efficiency of refueling missions. Whether the US Air Force will adopt the E-2D early warning aircraft ultimately depends on the attitude of the US Congress. However, the US Department of Defense and Air Force are considering canceling the E-7 early warning aircraft procurement plan, which may have a certain impact on the export of E-7 early warning aircraft. Analysts believe that France's choice of the "Global Eye" early warning aircraft and the US Air Force's consideration of using the E-2D early warning aircraft seem to indicate a trend towards miniaturization of early warning aircraft. Actually, this is just some countries' consideration based on their own situation. For example, France chose the "Global Eye" early warning aircraft not only considering its low procurement and maintenance costs, but also valuing its maritime surveillance and reconnaissance capabilities. Such multi-purpose small early warning aircraft are more suitable for countries with limited military spending, as they can simultaneously acquire multiple capabilities such as early warning, maritime surveillance, and reconnaissance at a lower price. The US Air Force is considering the use of E-2D early warning aircraft to reduce procurement and maintenance costs while meeting the requirements of its "agile combat deployment" concept. In fact, compared to small early warning aircraft, large early warning aircraft still have advantages. For example, in terms of carrying active phased array radar, large early warning aircraft can be equipped with larger radar arrays with more transmission/reception modules, which not only have a larger detection range and track more targets, but also have stronger anti-interference capabilities. Meanwhile, due to the presence of more command personnel, the command capability of large early warning aircraft is stronger than that of small ones. (New Society)