Russian military aircraft have been active in Syria since 2015 and by 2021 had flown over 40,000 sorties. About half these sorties were by helicopters and combat support aircraft carrying out reconnaissance missions seeking out targets and keeping track of enemy activity on the ground. Russia does not have many UAVs (Unmanned Aerial Vehicles) for recon or ground attack. Most of the UAV sorties over Syria were American or Israeli and in the last few years, Turkey has been using locally developed UAVs increasingly for recon and missile attacks.
Most precision attacks on ground targets have been carried out by the Russian equivalent to the American A-10. The Russian Su-25 is a 19-ton aircraft that carries a 30mm twin-barrel rotary cannon (with 250 rounds) and up to 5 tons of bombs and missiles, including air-to-air missiles. The twin-engine, one seat aircraft has a combat radius of 380 kilometers and a top speed of 900 kilometers an hour. Unlike the A-10, which has received similar upgrades to prolong its service life, the Su-25 has received fewer upgrades.
The Su-25 design is actually similar to the 19-ton American A-9, a competing design with the 23-ton A-10. The Su-25 and A-9 both are about 14 percent faster than the A-10. The A-10 is a more stable aircraft and much more resistant to battle damage. Absent lots of ground fire, both the A-10 and Su-25 are very effective against ground targets. The A-10 also has an edge with its unique multi-barrel 30mm autocannon, in addition to 7 tons of bombs. The A-9 could carry 8 tons, in addition to a 30mm autocannon.
The Su-25 has carried out about a third of the ground attack sorties by fixed wing jets. The only aircraft that accounted for more of these sorties is the Su-24, an elderly (1970s) design that used swing-wing technology pioneered by the 1960s American F-1111 and F-14 as well as the 1970s B-1 bomber. Russia copied this tech with its MiG-23/27 and Su-17/20/22/24 fighter-bombers plus the Tu-22 bomber. Only the Su-24 and Tu-22 designs proved successful and are still in use. The swing-wing design was made obsolete by new tech that improved flight chrematistics more effectively at less manufacturing and maintenance cost than swing-wing aircraft.
The Su-25 was by far the most successful emulation of any American design. The A-10 and Su-25 were the most popular, especially with ground forces, ground attack aircraft. While the A-10 was updated so it could handle GPS and laser guided smart bombs and guided missiles, the Su-25 was not. The Americans began using GPS and guided bombs and missiles in the 1990s and, by 2001, used their guided bombs almost exclusively because of their ability to hit targets with precision and enable an aircraft to destroy more targets during one sortie than aircraft using unguided bombs. Russia noted this and developed their own GPS and laser guided bombs. In Syria it was revealed that the Russians had effective smart bombs and missiles but could not afford to build and stockpile many of them. After about a year nearly all the bombing missions were with unguided bombs. This was not as much of a disadvantage as one would expect. While the smart bombs were being developed, so were more precise, computer-assisted fire control systems for aircraft using unguided bombs or autocannon for ground attack. Both the A-10s and Su-25s were equipped with this technology. Until the A-10 upgrades the modernized fire-control systems made ground attack more accurate whether using the autocannon or unguided rockets and bombs.
While the A-10 was well-protected against ground fire, more of it was encountered than expected and that justified upgrading the A-10s to use smart bombs from higher altitudes, only going low when using the autocannon, which was the main reason the A-10s and Su-25s were so popular with the ground forces. These two aircraft were designed and equipped to come in low and close to hit enemy targets near ground forces without causing any friendly fire losses.
Russia continues to upgrade and manufacture Su-25s. In early 2019 Russia sent four of the latest model SU-25SM3 aircraft to Syria. The Su-25 had been withdrawn from Syria in 2018 when one was brought down by Islamic terrorists using a shoulder-fired heat seeking missile. Since late 2015 Russia had maintained a force of about a dozen older model SU-25SM aircraft in Syria where they demonstrated how effective they were against Islamic terror groups armed with a wide variety of anti-aircraft weapons.
The SM3 upgrade includes a “self-protection” system that detects and defeats heat-seeking missiles as well as larger anti-aircraft missiles. The missile detection components of the self-protection system can also provide a location for anti-radar missiles the Su-25 is equipped to use. The SM3 version has an upgraded cockpit and fire control system. There is a larger HUD (Head Up Display) and the SM3 can handle a larger assortment of smart bombs and missiles. There are also improvements to the navigation and communications systems. The Su-25SM3 can operate at a higher altitude (over 4,000 meters) when using smart bombs. At this altitude most ground fire and portable anti-aircraft missiles cannot reach it.
Russia ordered 22 of its current 70 SM models upgraded to SM3 at the rate of four a year. The four SM3 aircraft sent to Syria were there, in part, for testing in a combat environment. That also helps any potential sales of upgrade services for other Su-25 users.
In 2018 another Su-25 crash in Syria killed the pilot. This was the 18th Su-25 lost since 2003, which is not unusual for a Russian military aircraft that has been in service since the 1980s. Despite these losses, the Su-25 is still a popular aircraft. When well maintained, the Su-25 is very effective and safe. Over a thousand have been produced since 1978. Production ended in 2017 but older models are being upgraded to the SM standard. Russia still finds export customers for the Su-25, both cheap used models and high-end versions like those upgraded to Su-25SM or SM3 standards.
As long ago as 1999, Russia decided to upgrade 80 of its 200 surviving Su-25 aircraft to the SM standard. In addition to extending service life by 10 years or more, the Su-25SMs have new electronics that permit the aircraft to use smart bombs and missiles. The fire-control system for ground attack was also updated. The navigation system was upgraded to include GPS and more automation. Many improved components were installed to reduce maintenance manpower needs by a third. Russia plans to keep 80 or so SU-25s in service until the 2030s. This was believed to include one more round of refurbishment and that turned out to be the SM3 upgrades. There are still several hundred Su-25s in use by export customers and some of these are interested in the SM/SM3 upgrades. The fact that the Su-25 performed well in Syria is a selling point. Then again Ukraine is currently using its older model Su-25s against Russian troops in Donbas, which is something of a recommendation as well but not one the Russians add to their marketing material.