MIAMI – On Saturday, July 11, the Civil Aviation Organization of the Islamic Republic of Iran (CAO.IRI) released the Factual Report of the Ukraine International Airlines (PS) 752 accident.
As this is the initial report, there will be little to no analysis contained. At this time, the flight recorders have not been read out.
Before the Flight
Two hours before the flight was due to take off, Iran changed the alertness level of the air defense. This change moved flight approval from the civilian system to the defense one.
Before this shift, the civil Air Traffic was approving flights to take off and informing their military counterparts.
After this shift, only the military was allowed to approve flights for take off.
The goal of this shift was to prevent miscommunications in the time of heightened alertness level.
PS752 Start Up
Two hours after the alertness change, PS752 requested to ATC to start up the aircraft engines. This request was passed to the Area Control Center, and then to the Air Defense Coordination Center.
The Air Defense Coordination Center gave clearance and this was transferred back to PS752. The flight then took off.
Within 10 minutes of take-off, the aircraft caught fire, made a right turn, and crashed near Shahedshahr.
All 176 passengers, 177 when counting an unborn child, perished in the crash.
Other Events That Morning
The relocation of an air defense system also occurred the same morning. Once relocated, the system needed north realignment, which was not conducted properly.
This meant that there was a 107-degree error in the targeting system of the defense unit. So while PS752 was departing Tehran, the defense system was seeing it as coming from the southwest and flying towards Tehran.
The operators at the air defense unit were unaware of this 107-degree error.
The target was communicated to the Coordination Center, but there was no response. Locally at the Air Defense Unit, the target was identified as a threat.
The Air Defense Unit fired a missile at the target, even though they had not received any response from the Coordination Center. This was an unauthorized firing.
At the time of the missile radio fuse activation, the aircraft transponder and ADS-B broadcast were terminated.
A second missile was fired, but the system recorded the strike as a failure.
While the final report has not been released yet, the investigators have stated some first findings.
The aircraft fuselage was analyzed and it was found that there was explosive residue that matched that in the defense system warhead.
While it is unknown if a missile was the cause, and which one, the investigators state that due to the termination of transmissions at the time of warhead 1’s fuse activation makes it likely that it caused functional damage to the aircraft.