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One of the basic tasks of an air defense battery is to discriminate between friendly aircraft and foe. But amid a state of high alert after Iran had launched a barrage of ballistic missiles at U.S. bases in Iraq, an Iranian air defense unit appears to have failed tragically, in a manner that some military experts contacted by Forbes found puzzling.
Canadian Prime Minister Justin Trudeau said Thursday that his country had evidence that a Ukrainian airliner that crashed Wednesday after the plane took off from Tehran’s Imam Khomeini airport had been shot down by an Iranian surface-to-air missile. All 176 aboard died, including 63 Canadians. Trudeau’s public accusation echoed reports by multiple news organizations citing anonymous sources stating that U.S. intelligence officials have made the same assessment.
Iranian authorities have denied that the plane was shot down.
Western intelligence officials reportedly believe that two missiles were fired at the airliner by an SA-15 Gauntlet air defense battery, also known as the Tor M1. It’s a Russian-made, mobile, short-range system that can accompany infantry units or provide a last line of defense for key infrastructure or military installations against low-flying jets, helicopters and cruise missiles. Mounted on a tracked vehicle or on a truck, it can be operated singly or with multiple launchers networked together to a command post.
It fires a missile with a small warhead containing 32 pounds of explosives that is designed to spray its its target with metal fragments.
A properly functioning SA-15 battery would have had multiple means of identifying Ukrainian International Airways Flight PS 752 as a civilian aircraft, defense experts told Forbes. One of several head-scratchers about the incident is that radar should have shown the Boeing 737-800 was on a commonly used flight path heading northwest from the airport — if it was inbound into the country it would be more explainable for it to have been misidentified as a hostile aircraft, says David Deptula, a retired U.S. Air Force lieutenant general who heads the Mitchell Institute for Aerospace Studies.
“There are a lot of question marks as to why and how this could have happened,” he says.
The Boeing 737-800 was transmitting a unique transponder identification code. If the equipment on the SA-15 that picks that up, called an IFF interrogator, was malfunctioning, battery operators would typically look at the schedule of airline traffic through their area and see if it matched with a scheduled flight, Deptula says. Flight PS 752 was delayed by almost an hour from its scheduled departure, taking off at 6:12 a.m.
The SA-15 operators also would have considered the path and speed of the plane on radar. “Is it operating at low altitude, at high speed headed toward a sensitive area”? Deptula asks. Flight PS 752 was rising toward 8,000 feet at a relatively sedate speed of 275 knots when flight tracking data from its transponder cut out, a normal profile for an airliner, he says. “It is departing the area, climbing through medium altitude, not trying to hide its signature, looking like a routine operation.”
Complicating decision-making for the soldiers operating the battery would have been two factors: time and the high state of alert.
The SA-15’s missiles have a relatively short range of 6 miles to 7.5 miles and it can detect targets at a range of 11 to 13.5 miles. It’s unknown if Iran has integrated its SA-15 batteries with its broader air defense network. If the unit in question was operating independently, at the speed the plane was going at, the soldiers may have had a window from as little as 30 seconds to 2.5 minutes to decide whether to launch an interceptor, says Carlo Kopp, co-founder of the think tank Air Power Australia.
Given that Iran had launched a barrage of ballistic missiles at two U.S. bases in Iraq hours before in retaliation for the targeted killing of the high-ranking Iranian commander Qassem Soleimani, Iranian air defense forces likely were operating under looser rules of engagement in anticipation of a potential counterstrike, as well as psychological pressure and fatigue after being on alert for the five days since his death.
“Your incentive balance sways over to shoot first, ask questions later,” says Michael Elleman, senior fellow for missile defense at the International Institute for Strategic Studies.
Exacerbating that would be their lack of experience – Iranian air defenses haven’t been tested since the Iran-Iraq War. The level of training of Iranian air defense forces is also a question mark.
Given the multiple means of detection and the distinctive flight profile of an airliner, there’s no excuse for the deadly mistake, says Kopp.
“The only credible explanation is incompetence,” he says. “There is no evidence that Iran is training its missileers any better than the Russians do,” he says, pointing to the downing of Malaysia Airlines Flight 17 over separatist-controlled eastern Ukraine in 2014, which a Dutch-led investigation concluded was hit by a Buk missile fired from a launcher that had been brought in from Russia, as well as incidents involving Russian-made and Russian contractor-operated air defense batteries in Syria.
But given the high speed and compressed timelines of modern air warfare, Elleman says we shouldn’t be surprised by what is believed to have happened to Flight PS 752.
“I’m surprised it doesn’t happen more often.”