Russia recently (March 2019) sent four of the latest model Sh-25SM3 aircraft to Syria. The Su-25 had been withdrawn from Syria less than a year earlier when one was brought down by Islamic terrorists using a shoulder fired heat seeking missile.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 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 and at this altitude most ground fire, and portable anti-aircraft missiles, cannot reach it.
Russia has 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 early 2018 another Russian Su-25 ground attack aircraft crashed killing the pilot. All Su-25s were immediately grounded until the cause of the crash could be found. 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 were produced since 1978. Production ended in 2017 but older models are being upgraded to the SM standard. In 2006, after seven years of work, Russia put the first two Su-25SM upgrades into service. Six more were delivered within a year. 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.
Russia still maintains a force of Su-25s. As long ago as 1999, Russia decided to upgrade 80 of their 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 navigation system has been upgraded, to include GPS and more automation. Many improved components were installed, to reduce maintenance manpower needs by a third. Currently, 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 and that is something of a recommendation as well.
The 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. It's the Russian equivalent of the U.S. A-10, which has received similar upgrades to prolong its service life.
The Su-25 design is actually more 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. But 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 the same 30mm autocannon.