Updated: Jul 14
On 12 July 2020, Iran's Civil Aviation Authority released an updated factual report of Ukraine International Airlines (UIA) Flight 752 that was shot down over Iran due to human error. UIA flight 752, operated by a Boeing 737-800, was shot down by the Iranian army shortly after take-off from Tehran on 8 January, 2020.
A Ukraine International Airlines Boeing 737-800, similar to the one involved in the incident. Photo by Karam Sodhi | AeroNewsX
According to the updated report, on 8 January 2020, one of the air defence units in Tehran was relocated. Iranian investigators discovered that during the relocation, one of the defence units was misaligned by 107 degrees, a failure caused by human error. As such, the direction of objects and targets detected by the system increased by 107 degrees.
At around 5 am (Iran time), Iran's air defence system alertness level was raised and only flights that were detected and cleared for flight operations by the flight defence system would be allowed to take off. UIA Flight 752's request for start-up clearance was approved by the Air Defence Coordination Center at 6:53 am and at 7:10 am, UIA flight 752 was cleared for takeoff by the Tehran Air Traffic Control.
Three minutes after taking off, the air defence operator detected a target flying towards the defence unit from the Southwest but at the same time, UIA flight 752 was flying towards the defence unit from the southeast. The target was UIA flight 752 but due to the human error when aligning the air defence unit, the aircraft appeared to be flying from the southwest.
The misalignment error was exacerbated by the operator's failure to identify the target as a passenger aircraft. The defence unit operator wrongly identified the aircraft as a threat and fired a missile at the target without authorisation from the Air Defence Coordination Center. Standard Operating Procedures of the defence unit indicates that the operator is not authorised to fire if they do not receive fire command from the coordination centre.
The first missile fuse was activated and the aircraft Automatic Dependent Surveillance-Broadcast (ADS-B) signals were lost. However, the defence system continued to lock on the target and by observing the continuity of the aircraft trajectory, the operator launched a second missile towards the target.
Shortly after the second missile was launched, the aircraft made a right turn and evidence showed that the aircraft was on fire. The aircraft managed to remain in the air for three minutes before crashing into a playground in Khalajabad. The aircraft exploded on impact, killing all 176 passengers and crew.
The report states that "Effects produced by the explosives on the aircraft fuselage were analysed, and it was found that they have similarities to the expected ones of the detonation of the defence system warhead." It added by stating that "the sequence of events clearly shows the occurrence of a chain of events initiated by a human error. Up to this point, some important contributing links in the chain of events have been identified, which have led to targeting the aircraft mistakenly."
Investigations to this incident are still ongoing and the final report and conclusion have yet to be released.