Less than a week after Malaysia Airlines Flight 17 was shot down over eastern Ukraine, two Ukrainian SU-25 “Frogfoot” fighter jets were blown out of the sky. Pro-Russian separatists claimed they downed the aircraft with easy-to-use shoulder-fired missiles, while the government in Kiev insisted the two aircraft were well out of range of so-called MANPADS, hinting that a more advanced system was to blame.

U.S. intelligence officials have said Flight 17 was likely destroyed with one such advanced system, an SA-11.

In the case of the Frogfoots, the pilots managed to eject from their aircraft, landing somewhere in separatist-controlled territory. Without their testimony, it is impossible to determine exactly what shot down the aircraft.

The Ukrainian government declared that both jets were flying at 17,000 feet, which would have put them out of range of most MANPADs, including the SA-7, which the separatists are believed to possess. However, if the Ukrainian SU-25s were flying within the range of MANPADS, they could have been critically damaged by an attack involving multiple missiles fired simultaneously, known as volley fire.

The design of the Soviet SU-25 is heavily based on the American A-10, both of which were designed to provide close air support at low altitudes. As a ground attack fighter, the Su-25 was built specifically to withstand attacks from weapons fired from the ground like the SA-7. The Soviets did this by incorporating two engines, an up-armored cockpit that could withstand heavy machine gun fire and reinforced elevator control rods.

The SU-25’s twin engine design was implemented specifically with heat-seeking missiles like the SA-7 in mind. As heat-seeking missiles usually track toward the hottest part of the airplane, the engine exhaust, the two engines allowed for redundancy in case one engine was damaged in a strike.

A review of footage from one the SU-25 crash sites this week reveals that one of the aircraft’s wings suffered some sort of fragmentation damage, yet it is unclear what caused it. The damage from heat-seeking shoulder-fired missile strikes is usually localized around the exhaust of the aircraft’s engine.

Possible shrapnel damage to the wing of a Ukrainian SU-25 (YouTube screen grab)

A complex surface-to-air missile like the SA-11, by contrast, would be more likely to cause damage to an aircraft’s wings as the missile detonates and fragments pepper the aircraft with shrapnel. That said, it’s impossible to know whether the damage was the result of small arms fire from previous engagements or trigger-happy separatists.