Is it possible for an SU-25 to fly high enough to shoot down a Boeing 777?

Question

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

Answer 1

Scott Locklin wrote an excellent answer to this question.

• 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.

Results of an R-60 hitting a jet engine on a BAe-125-800A.

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.

Answer 2

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.

Answer 3

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)

Answer 4

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.

Answer 5

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.