A common theory from pro-Russian netizens surrounding the MH-17 tragedy is that it was a Ukrainian SU-25 ground attack fighter plane which shot down the civilian airliner. However, MH-17 was flying at 10,500m when the service ceiling of an SU-25 is 7,000m. They say that this discrepancy is made by the fact that the Ukrainian pilot used afterburners to get to the height MH-17 was flying at. Is this actually technically possible?

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    $\begingroup$ @shortstheory I guess the rumour specifically mentions the Su-25 because they were being used in the area around the time: one of them was shot down a few days before the MH-17 shoot-down, for example. $\endgroup$ – David Richerby Aug 27 '14 at 8:17
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    $\begingroup$ @shortstheory actually an Su-25 is less "wimpy" than a MiG, it can take a far heavier beating and remain flying. It's heavily armoured to survive in ground attack missions in support of ground troops, while being shot at. $\endgroup$ – jwenting Aug 27 '14 at 12:57
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    $\begingroup$ @shortstheory they never do, you also have to consider what its mission is. And its mission doesn't require high speed or a high service ceiling (though the latter can be handy for ferry flights of course, but then again do you give a bulldozer roadwheels so it can drive on the motorway? of course not.) $\endgroup$ – jwenting Aug 28 '14 at 5:01
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    $\begingroup$ It would be hard for a pilot to use afterburners on an Su-25, since it is powered by non-afterburning turbojets! :) $\endgroup$ – egid Aug 28 '14 at 6:12
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    $\begingroup$ Looking at the multiple comments, this has been turned into discussing the conspiracy theory as much as (if not more than) the capability. I don't think it was necessary to develop the theory. Asking what is the ceiling of the Su-25, and how it can be exceeded would have been sufficient. No? $\endgroup$ – mins Sep 30 '15 at 17:30

There is an excellent answer at http://scottlocklin.wordpress.com/2014/07/21/can-the-su-25-intercept-and-shoot-down-a-777/

  • The SU-25 is a ground attack fighter unsuited to intercepting and/or shooting down 777s. If the Ukrainian air force wanted to do so, they have better aircraft available.
  • The SU-25 max speed is slower than a cruising 777.
  • The SU-25 has an operational ceiling of 16000 ft with max weapons to 23000 ft clean, MH17 was at 33000 ft.
  • It is an unpressurised aircraft.
  • As a ground attack aircraft it probably only rarely carries air to air missiles. It can carry the R-60 infra-red air-to-air missile which has a 6 lb warhead effective against small aircraft.
    • An R-60 once hit and destroyed one engine of a small BAE 125 business jet at 35000 ft but failed to bring it down, apparently the missile failed to explode.
    • KAL902, a Boeing 707, was hit by an R-60 and made an emergency landing 40 minutes later.
  • The R-60 is a short-range missile (5 miles). The Russians claim the SU-25 came within two or three miles of MH17.

On the whole this makes the SU-25 a poor choice for shooting down a cruising 777.

It seems unlikely that a 777 would be shot down in this way. Not impossible, but far less likely than other proposed scenarios such as those involving BUK (SA-11) ground to air missiles.

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Results of an R-60 hitting a jet engine on a small business jet.

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Results of an R-60 hitting a Boeing 707 ... two R-60s were launched, one missed.

These R-60s were fired by supersonic interceptors, not by SU-25 ground-attack aircraft.

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    $\begingroup$ Any idea why these pro-Russian netizens accuse the SU-25 instead of accusing a more suitable fighter available to Ukraine? I wonder if what's happening here is that some very sloppy conspiracy theorists are getting in the way of more competent attempts to blame it on Ukraine by creating a ready-made straw man argument ;-) $\endgroup$ – Steve Jessop Aug 26 '14 at 18:15
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    $\begingroup$ @SteveJessop: I suspect the accusation was primarily intended for domestic audience as Putin gained huge popularity with the aggressive approach to Ukraine and couldn't admit mistake. And for commoners accusing Su-25 that is known to operate in the area might be more believable than accusing more suitable fighter that nobody mentioned so far though it makes the accusation clearly false to the knowledgeable. The accusation came from Ministry of Defence, so sloppy conspiracy theorist don't sound likely. $\endgroup$ – Jan Hudec Aug 26 '14 at 21:24
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    $\begingroup$ @SteveJessop ever met a conspiracy theorist who knew what he was talking about? If you can come up with an improbable aircraft for the scenario, you can dream up improbable things like rocket engines strapped under the wings to get it up there as well (not that farfetched, such things were attempted with interceptors in the 1950s, but not realistic in this case, especially as the missile tracks coming out of Russian held territory intercepting the airliner were recorded). $\endgroup$ – jwenting Aug 27 '14 at 6:37
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    $\begingroup$ @jwenting: The missile track is what I am most willing to discredit, because that is a word of USA Ministry of Defense (claiming to have recorded the track) against work of Russian Ministry of Defense (pushing this Su-25 theory). I consider the comments made by the separatists on Twitter and then deleted as more important evidence because the dynamics of the situation would make that much more difficult to fake. $\endgroup$ – Jan Hudec Aug 27 '14 at 7:20
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    $\begingroup$ @JanHudec me too, I have my doubts about anyone's ability to record a missile track on radar like that unless they're deliberately looking for it at the time. And the US had no reason to have assets looking for missile tracks over the Ukraine that day. $\endgroup$ – jwenting Aug 27 '14 at 7:27

You're asking 4 things here:

  1. Can aircraft fly higher than their stated service ceiling?

    Service ceiling can be exceeded, depending on the aircraft type, loadout, atmospheric conditions, and flight profile, but usually not very far or for very long.

  2. Does an SU-25 have afterburners?

    The SU-25 (NATO reporting name Frogfoot) has no afterburners, so that part of the claim is bonkers.

  3. Does an SU-25 have the capability to shoot down aircraft?

    It can carry light IR guided missiles for self defense, and of course has a gun, but would have no way to intercept an airliner at altitude, it doesn't have the endurance there nor the equipment to detect and track the aircraft (though in theory a ground controller could guide it of course).

  4. Would an SU-25 be used for an intercept like that?

    Why should the Ukraine use an SU-25 ground attack aircraft when they have dedicated air defense fighters far more capable for the job?

So no, the claim is utterly bonkers.

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    $\begingroup$ The SU-25 has a very powerful gun, though--it's meant to tear through tanks, it certainly could shred an airplane. Finding it, getting up there and getting hits would be very problematic indeed, though. $\endgroup$ – Loren Pechtel Aug 26 '14 at 22:47
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    $\begingroup$ @LorenPechtel yes, it does (as I mentioned). And weirder things have brought down aircraft. For example in Iraq a USAF A-10 brought down a helicopter by dropping a 500lb bomb on it :) $\endgroup$ – jwenting Aug 27 '14 at 6:34
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    $\begingroup$ @LorenPechtel: Yes it does. But for one thing if it can't reach the altitude, the distance would be rather large for good aim and for another the damage would look different from the shrapnel damage that was actually observed. $\endgroup$ – Jan Hudec Aug 27 '14 at 7:00
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    $\begingroup$ … which leads me to another argument. The debris show shrapnel damage to the front section of the aircraft. That is not consistent with IR-guided missile which would go for the engines from behind nor with cannon with shells exploding on contact. It also indicates heavier warhead than the few kg found in most air-to-air missiles. $\endgroup$ – Jan Hudec Aug 27 '14 at 7:05
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    $\begingroup$ @JanHudec Most A2A missiles use proximity fuses and there are an enormous number of variables determining the area of the aircraft taking the brunt of the damage. Because the nose is peppered means nothing. Nor does the amount of damage correlate to the assumed weight of the warhead. The conspiracy theory is, as they always are, nonsense but the size and area of damage are not indicators (without other evidence) to prove or disprove air-2-air or ground-2-air. $\endgroup$ – Simon Aug 27 '14 at 19:58

Parabolic trajectories above the service ceiling are possible. Just go up fast enough, and rely on inertia instead of lift to carry you upwards.

Of course, parabola's have the property that there's a long way up, a sharpish bend at the top, and a long way down again. That's not a practical way to intercept another aircraft, especially if your plane isn't designed to use off-board AA radar guidance to get the intercept course right (and a ground attack aircraft like the SU-25 wasn't designed like that at all - The Soviets had proper high-altitude interceptors for that)

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    $\begingroup$ More importantly you are exchanging speed for altitude, so at the top you are flying slower. And you must still fly fast enough to be above stall speed and (true) stall speed increases with altitude. So the aircraft would have to fly very fast before starting the climb. With the altitude difference probably faster than it's actual top speed. $\endgroup$ – Jan Hudec Aug 26 '14 at 20:49
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    $\begingroup$ To put some numbers out: Looking over how the zero-g flights are conducted we find that you can trade 260kph for 1000m of height. With more engine power you could get higher but you still have to fly a course between the Scylla of mach buffet and the Charybdis of stall and unless I'm making a math error you're not going to get 2000m out of it. $\endgroup$ – Loren Pechtel Aug 26 '14 at 23:02
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    $\begingroup$ Flying on such parabolic trajectories also reduces the aircraft's ground speed as most of the speed is in the vertical direction. Which means it makes the already slow aircraft very much slower than the 777's cruising speed. So the only viable way for it to work is if the pilot starts climbing very far ahead of the 777 hoping to reach max altitude exactly when the 777 arrive. That's just silly. $\endgroup$ – slebetman Aug 27 '14 at 14:54

It would not be impossible for a Su-25 "Frogfoot" carrying AA-8s to down an airliner, but it's very unlikely.

First off, let's get something out of the way; neither the R-95Sh engines on early variants, not the improved R-195 on the Su-25T variant, has an afterburner. The Su-25's primary mission profile requires it to fly low and slow over the battlefield to acquire and engage ground targets (it's the Russian answer to the A-10), and its low amount of wing sweep prohibits supersonic flight, so an afterburner is not only completely unnecessary, it's downright dangerous to try to use in a design like this. So, the idea that a Su-25 used afterburners to exceed its service ceiling is pure bunk.

A Su-25, flying at its mission ceiling of 16,000 feet (which would require the pilot to be on oxygen, which would be available), targeting a 777 at 33,000 feet, would be about 3.5 miles away, vertically, from the airliner. That's well within the range of the R-60 Molniya/Vympel, aka the AA-8 Aphid. However, it would require the pilot to point the aircraft directly upward at the airliner, which would very likely cause the Su-25 to stall before the pilot could get a good lock-on.

The maximum targeting range of the AA-8 is believed to be 5 miles; it can fly 6 miles after launch, but keep in mind the missile has to get to where the target aircraft was when launched, then cover the additional distance the aircraft has covered in that time (the missile would also have to climb 3 miles against gravity and would get none of that energy back "falling" toward the target as many air-to-air missiles do). Given the 3.2 mile vertical separation, the minimum angle the Su-25 pilot would be required to maintain assuming a "boresight" lock-on is required (the aircraft's nose has to point right at the target) is $\sin^{-1} \dfrac{3.2}{5} = 40^o$, and so the 777 could be no further in any horizontal direction from the Su-25 than $\cos (40) * 5 = 3.8$ miles. Some sources claim the R-60 can lock on at up to 45 degrees off-boresight, which would mean the Su-25, if it got a clean "uncaged" IR lock on the 777, could fire from level flight.

So, in theory, a Su-25, at its service ceiling and closer than 3 miles horizontally from MH-17, could have shot it down. However, there are no reports from civilian or military sources that an Su-25 was anywhere near that close to MH-17, and make no mistake, a Su-25 flying at 16,000 feet would be highly visible on any radar system for a hundred miles in any direction; the Frogfoot has exactly zero radar stealth features.

The German/American intelligence reports on the incident, stating that Russian-allied rebels in the Donetsk Oblast area used an SA-11 Gadfly launcher to bring it down, are more consistent with reality. This self-propelled SAM system is perfectly capable of reaching 33,000 feet (its vertical range is over 80,000 feet; it was designed with the CIA's U-2 Dragon Lady in mind) and can target an aircraft up to 20 miles away at that altitude. In addition, a Ukranian An-26 operating in the area was shot down by a similar launcher, according to the same rebel militia's own statements.

Why anyone would have targeted the civilian airliner is not known. There are several theories:

  • The separatists may have mistaken MH17 for another Ukrainian transport plane; a UAF An-26 light transport was shot down in the same area by an SA-11 just three days prior to MH17.
  • The Ukrainians might have fired on the plane, believing it to be "Board One", Putin's personal VIP transport which would have been on its way back from Brazil around that time, and which has reportedly used routes overflying Ukraine before. The Russians state the president's Il-96 was nowhere near Ukraine at the time and there were no plans to overfly the airspace during the trip to Brazil. At any rate, the Ukranians of course deny targeting any civil transport, Russian or otherwise.
  • The separatists may have believed it to be the same plane and fired on it, thinking that an assassination, pinned on the Ukrainians, would spark a full-scale Russian invasion of Ukraine thus accomplishing their goals.
  • The separatists may have intended to implicate Ukraine in the downing of a civilian airliner, weakening international support of the Ukrainian government.
  • The separatists may have deliberately targeted the civilian airliner as a message to keep civilian air traffic away from Ukraine. If they're in possession of more SAMs (highly likely; even the one launcher would have had 3 on the rails and been accompanied by a supply truck with more), ensuring no civilians are in the area means any aircraft in sight from then on is Ukrainian.
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    $\begingroup$ Thanks for your answer, but why are you answering this when a similarly good answer has been accepted over a year ago? $\endgroup$ – Evil Washing Machine Sep 30 '15 at 20:21

One other note to add to this... if you read the very thorough Dutch investigation, you find that MH17 was brought down by a fragmenting warhead exploding near the aircraft cockpit. The fragment pattern found on the cockpit skin wreckage is consistent with a missile approaching from the front, at an upward angle.

That is clearly a radar guided missile, approaching from the front. If this had been a heat seeking missile, it would have struck or exploded near one of the engines. The cockpit of a 777 doesn't emit any heat, while the engines definitely emit heat.

Since the SU25 doesn't carry radar guided missiles, just heat seekers, this is another reason that a SU25 would not have been able to produce the damage that was found on the wreckage. Nor does the SU25 carry a radar transmitter compatible with radar guided missiles, so even if a radar guided missile could be mounted, it would not have a radar source to illuminate the target.

Finally, the Dutch investigation also found warhead fragments consistent with a Buk antiaircraft missile, large interlocking fragments, some with a bow tie shape, instead of the smaller rodlike fragments that most heat seekers use.

  • $\begingroup$ thats not the question here. the question is, could the su-25 fly high enough. also, nobody here seems to address the engine variants. some su-25s have more powerful engines with afterburners. does ukraine possess any su-25s with newer engines? how high can you get with 0 payload, and say 20% fuel with those engines? looks like people are too eager here to dismiss conspiracy theorists than give a good answer. $\endgroup$ – user2914191 Jun 18 '19 at 16:50

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