Main Image Credit Courtesy of mehrnews.com/Wikimedia Commons
Piecing together the evidence for the tragedy.
As the leaders of Canada, the US and the UK announce that there is strong evidence that Iranian surface-to-air missiles (SAMs) shot down Ukrainian International Airlines flight PS752 soon after it took off from Tehran airport bound for Kiev on 8 January, there are urgent questions to be asked and significant implications for both the Iranian regime and US President Donald Trump. All 176 people on board were killed in the crash, first thought to be an accident caused by a mechanical failure or possibly a bomb on board.
No Clear Motives
There were a host of reasons why a SAM attack on the airliner initially appeared extremely unlikely, despite the fact it occurred during an Iranian missile offensive on US airbases in neighbouring Iraq, with the region braced for a further escalation spiral.
First and foremost, neither the Iranian regime, nor the Islamic Revolutionary Guard Corps (IRGC) or the US government – the main players in the confrontation – had any motive to target the Ukrainian International Airlines flight. Most of the passengers were Iranian or Canadian citizens – a mix almost guaranteed to put even the most cynical plot off targeting this particular flight. Safe commercial aviation access is a cornerstone of most modern economies, and Iran has worked hard to restore a starved commercial aviation sector since decades of crippling sanctions on aerospace components were partially lifted following the conclusion of the Joint Comprehensive Plan of Action, as the 2015 nuclear deal with Iran is formally called. The Iranian state also acquires valuable foreign currency from overflight fees paid by airlines using the airways above the country. So, despite a long-suspected involvement in terrorist attacks against airliners abroad in the past, Iran has no reason to want to make its own airspace seem unsafe for civil air traffic. Iran was also under close surveillance by both sides due to the crisis, meaning a covert missile attack would have been unlikely to go undetected.
Having safely ruled out a deliberate attack, there are also strong reasons to think that an accidental targeting of this airliner should not have been possible. First, the airliner was transmitting active identification and position data via standard radar transponder, and had just taken off from Tehran airport under radar control and full contact with Tehran Air Traffic Control, according to a pre-filed flight plan. Therefore, it should have been on the expected civilian traffic logs and the common air picture normally supplied to both air defence command centres and SAM units, especially at times of heightened tension.
Second, the Boeing 737-800 jet was plainly a large and slow-moving aircraft, which was climbing out at around 8,000 ft on a well-used civil flightpath, out of a busy international airport when it was apparently hit. Even without having been made directly aware of this flight, a SAM operator crew should have easily been able to identify that this flight pattern and radar profile was completely at odds with any suspected US missile or combat aircraft strike package.
Third, Tehran airport is comparatively distant from Iran’s borders – it is an unlikely place for the first contact to be made against a US missile or combat aircraft strike package. In the absence of threat warnings from radar and SAM units watching Iran’s borders intently as the IRGC’s own ballistic missile strike hit US airbases in Iraq, it must have involved either a major leap in imagination or complete communications blackout for the SAM operators near Tehran to assume that Ukrainian flight PS752 was hostile. There were no US attacks into Iranian airspace – and unlike other negligent accidental shoot-downs of airliners in the region, such as Iran Air 655 by the US Navy on 3 July 1988 or the Malaysia Airlines Flight MH 17 shot down on 17 July 2014 by Russian-supplied rebel forces in Ukraine – flight PS752 was not detected under circumstances that could even semi-credibly lead to the aircraft’s misidentification as hostile.
So what actually happened? The most likely culprit appears to be a Russian-made SA-15 ‘Tor M-1’ SAM system based near the Mehrabad Airbase on the outskirts of Tehran. Photographs from the morning of 9 January, which claimed to be from the crash site, showed the distinctive tail section and nose cone of the 9K331 missile fired by the SA-15. Iran is known to operate the system, designed to be a mobile and self-contained short-range defence asset for Russian army units against missiles and low-flying helicopter gunships in a war with NATO. As a short-range mobile defence SAM, the SA-15 is designed to be effective without being linked up to a wider national air defence radar picture, although it can still integrate such information via datalink and radio communications where available. However, it is more credible that Iranian air defenders manning an SA-15 would be operating without a solid picture of the known traffic in Iranian airspace as a whole than crews of larger and more static SAM types.
Before making public claims of Iranian SAM launches in such unlikely circumstances, the US is likely to have identified the infrared signature of the SAM launches and the destruction of PS752 using orbital surveillance capabilities such as SBIRS, as well as the radar signature of an SA-15 engagement using an asset such as an RC-135W standoff spy plane.
The most likely scenario is that a badly trained or inexperienced crew of an SA-15, exhausted after being on alert for days during the US–Iran standoff and scared of being hit as part of a retaliatory US strike following the ballistic missile attacks on bases in Iraq, made a series of tragic and incorrect assumptions when PS752 appeared on their radar screen. Perhaps operating in emission-control conditions to avoid being detected and targeted by the US, they might have had a reduced situational awareness picture. As has been seen with previous shoot downs such as Iran Air 655, once incorrect assumptions have been committed to by a SAM crew, confirmation bias is often enough during a rapid decision and engagement sequence to make them ignore logical indications to the contrary.
This disaster is terrible news for the Iranian regime in terms of international and domestic perceptions, and comes at a time when it had been perceived by many to have responded with restraint to the killing of General Soleimani. Beyond lethal incompetence on the part of a SAM crew pointing to the inadequacy of organisational training and procedure in the Iranian Air Defence Force, bulldozing the wreckage to prevent air crash investigators doing their job is an altogether more malicious act which will invite further condemnation.
The views expressed in this Commentary are the author’s, and do not represent those of RUSI or any other institution.
Research Fellow, Airpower & Technology