Locklin on science

Can the Su-25 intercept and shoot down a 777?

Posted in big machines, War nerding by Scott Locklin on July 21, 2014

Personal background: I’ve flown Malaysian Airlines and declare it better and more civilized than any US airline. I’ve been to Ukraine on a business-vacation. I’m sympathetic to the aspirations of the long suffering Ukrainian people. I’m also sympathetic to the position of the Russian government with respect to Ukraine, which is, after all, sort of like their version of Canada, if Canada had annexed part of New England in 1991. I am not sympathetic to the claque of sinister war mongers and imperial Gauleiters in the US State department with respect to their activities in Ukraine and towards Russia. If I had my way, creeps like Vicky “fuck the EU” Nuland and Geoff Pyatt would be facing prison and the firing squad for what they’ve done over there. In my opinion, US policy towards Russia since the fall of the Soviet Union has been knavish, evil and disgusting. My opinion isn’t a mere slavophilic eccentricity; George Kennan, our greatest Cold War diplomat, said more or less the same things before he died.

If this was a shoot down by Donetsk separatists, and even if the Russians supplied the missiles to the separatists (who could have captured them from Ukrainian forces, or simply borrowed a couple from the local arms factories), this doesn’t make the Russians culpable for the tragedy. By that logic, the US is responsible for all the bad things done with weapons it supplies to its proxies, such as ISIS in Syria and Iraq, which is arguably worse. Certainly the US is responsible for the escalation of the situation in Ukraine. I say all this, because passions are high, and the war drums are beating. I am not a  war monger, or apologist for anybody; in fact, I’m the closest thing you’re going to get to an unbiased observer in this disaster. I have no horse in this race. I wish they’d all learn to get along.

So, the Rooskies are now implying that a Ukrainian Su-25 may have shot down flight MH17. Facts and objective reality seem to be in short supply in Western coverage of the Ukraine crisis; I aim to supply some. I am going with the assumption that the Rooskies are telling the truth, and that there was indeed a Ukrainian Su-25 where they said there was. They said the Su-25 came within 2 to 3 miles of the 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

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-60 is 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 incident where 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

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. It could have been the Buk SA-11/17 with its 150lb warhead and 75,000 foot range, just like everyone is reporting. Another candidate is the Kub SAM, which is an underrated SAM platform also in use in that part of the world. Yet another possibility is the S-125 Pechora, which isn’t deployed in Ukraine or Russia, but it is probably still manufactured in the Donbass region. A less likely candidate is the S-75 Dvina (the same thing that took out Gary Powers), though the primitive guidance system and probable lack of deployed installations in Ukraine and Russia make this unlikely. The fact that the MH17 disappeared from radar at 33,000 feet, and the condition of the wreckage indicates it was something really big that hit flight MH17; not a piddly little aphid missile. The pictures of the wreckage don’t indicate any sort of little missile strike which might have knocked off an engine; it looks like the whole plane was shredded. Both engines came down in the same area, more or less in one piece.

Whatever it was, it wasn’t an Su-25. There is also no use going all “Guns of August” on the Russians over something that was very likely beyond their control. Here’s hoping all parties concerned learn to resolve their differences in a civilized manner.

War is bad, m'kay?

War is bad, m’kay?

Interesting links from the rumor mill (as they come in):


Update July 22:
Nobody else has yet noticed that Donetsk manufactures SAMs, or that there are several other potential sources and varieties of such weapons. The Russians are sticking with the Su-25 idea, and haven’t corroborated the Su-27 story, making it seem much less likely.

“Blame the Rooskie” war mongers would do well to remember the Vincennes incident, where the US shot down an Iranian air liner over Iranian airspace, killing a comparable number of innocent civilians.

Update July 23:
A run down of some of the capabilities of the Buk system from “The National Interest” (one of the few sane US foreign policy periodicals):


 Update Aug 16:

A SAM based video game