If you want to believe the crackpot idea that Ukrainian government were a bunch of sinister schemers who shot down MH17 on purpose, an Su-25 is pretty much the worst armed military aircraft you can imagine for such a task. The Ukrainian air force has a dozen Su-27s and two-dozen Mig-29s perfectly capable of intercepting and shooting down a 777. They also have the Buk missile, and are capable of placing it somewhere near the Donetsk separatists if they wanted to make them look bad. So, the theory that the evil Ukrainians shot down a 777 with a Su-25 on purpose is … extremely unlikely.
quote from
https://scottlocklin.wordpress.com/2014/07/21/can-the-su-25-intercept-and-shoot-down-a-777/
Everyone agrees that the Boeing 777-200ER was flying over the separatist region at 33,000 feet. A Boeing 777’s cruising speed is about 560mph or Mach 0.84. Its mass is about 500,000 pounds, and it has a wingspan and length of about 200 feet each. The MH17 was flying from West to East, more or less.
The Su-25 Frogfoot is a ground attack aircraft; a modern Sturmovik or, if you like, a Rooskie version of the A-10 Warthog. The wingspan and length of the Su-25 is about 50 feet each, and the mass is about 38,000lbs with a combat load. The ceiling of an unladen Su-25 is about 23,000 feet. With full combat load, an Su-25 can only make it to 16,000 feet. This low combat ceiling was actually a problem in the Soviet-Afghanistan war; the hot air and the tall mountains made it less useful than it could have been. At altitude, the maximum speed of the unladen Su-25 is Mach 0.82; probably considerably lower with combat loads. For air to air armament, it has a pair of 30mm cannons and carries the R-60 missile. The Su-25 is also capable of carrying the Kh-13, though it is not clear that the Ukrainians deploy this missile on their Su-25s. For the sake of argument, we’ll talk about it anyway.
Since it was a Ukrainian Su-25, we can also assume it was heading West to East; more or less the same trajectory as flight MH17. It could have been traveling in some other trajectory, but we can already see the problem with an Su-25 intercepting a 777; it’s too low, and too slow. If you want to believe the crackpot idea that Ukrainian government were a bunch of sinister schemers who shot down MH17 on purpose, an Su-25 is pretty much the worst armed military aircraft you can imagine for such a task. The Ukrainian air force has a dozen Su-27s and two-dozen Mig-29s perfectly capable of intercepting and shooting down a 777. They also have the Buk missile, and are capable of placing it somewhere near the Donetsk separatists if they wanted to make them look bad. So, the theory that the evil Ukrainians shot down a 777 with a Su-25 on purpose is … extremely unlikely.
Could an Su-25 have shot down a 777 by accident? Fog of war and all that? Perhaps they thought it was a Russian plane? Well, let’s see how likely that is. The weapons of the Su-25 capable of doing this are the cannons, the R-60 missile (and its later evolutions, such as the R-73E) and the K-13 missile.
Cannons: impossible. The Su-25 was at minimum 10,000 feet below the 777. This means simply pointing the cannon at the 777 without stalling would have been a challenge. The ballistic trajectory of the cannon fire would have made this worse. The Gsh-30-2 cannon fires a round which travels at only 2800 feet per second, significantly lower than, say, the round fired by a 338 Lapua sniper rifle. Imagine trying to shoot down an airplane with a rifle, from 2-3 miles away using your eyeball, in a plane, at a ballistic angle. If the MH17 was somehow taken out by cannon fire, it will have obvious 30mm holes in the fuselage. None have been spotted so far.
K-13 missile: extremely unlikely. The K-13 is a Soviet copy of the 50s era AIM-9 sidewinder; an infrared homing missile. Amusingly, the Soviets obtained the AIM-9 design during a skirmish between China and Taiwan in 1958; a dud got stuck in a Mig-17. It is not clear that the Ukrainian air force fields these weapons with their Su-25’s; they’re out of date, and mostly considered useless. Worse, the effective range of a K-13 is only about 1.2 miles, putting the 777 out of effective range. Sure, a K-13 miiiight have made it to a big lumbering 777 with its two big, hot turbofans, but it seems pretty unlikely; a lucky shot. The 16lb of the K-13 warhead is certainly capable of doing harm to a 777’s engines. Maybe it would have even taken out the whole airliner. Doubtful though.
The K-13 AA missile
R-60 missile: extremely unlikely. If a Su-25 was firing missiles at a 777, this is probably what it was using. The R-60is also an IR guided missile, though some of the later models use radar proximity fuzing. Unlike the K-13, this is a modern missile, and it is more likely to have hit its target if fired. Why is it unlikely? Well, first off, it is unlikely the Ukrainian Su-25s were armed with them in the first place: these are ground attack planes, fighting in a region where the enemy has no aircraft. More importantly, the R-60 has a tiny little 6lb warhead, which is only really dangerous to fragile fighter aircraft. In 1988, an R-60 was fired at a BAe-125 in Botswana. The BAe-125 being a sort of Limey Lear jet, which weighs a mere 25,000lbs; this aircraft is 20 times smaller than a 777 by mass. The BAe-125 was inconvenienced by the R-60, which knocked one of its engines off, but it wasn’t shot down; it landed without further incident. A 777 is vastly larger and more sturdy than any Limey Lear jet. People may recall the KAL007 incidentwhere an airliner was shot down by a Soviet interceptor. The Su-15 flagon interceptor which accomplished this used a brobdingnagian K-8 missile, with an 88lb warhead, which was designed to take out large aircraft. Not a shrimpy little R-60. The R-60 is such a pipsqueak of a missile, it is referred to as the “aphid.”
The R-60 aphid
That’s it; those are the only tools available to the Su-25 for air to air combat. The other available weapons are bombs and air to surface missiles, which are even more incapable of shooting down anything which is 10,000 feet above the Su-25.
My guess as to what happened … somebody … probably the Donetsk separatists (the least experienced, least well trained, and least well plugged into a military information network), fired a surface to air missile at something they thought was an enemy plane.
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