UI Boeing 737-8KV (WL) UR-PSR,

ASN Wikibase Occurrence # 319260

Date:	Wednesday 8 January 2020
Time:	06:18
Type:	Boeing 737-8KV (WL)
Owner/operator:	Ukraine International Airlines
Registration:	UR-PSR
MSN:	38124/5977
Year of manufacture:	2016
Engine model:	CFMI CFM56-7B24E
Fatalities:	Fatalities: 176 / Occupants: 176
Aircraft damage:	Destroyed, written off
Category:	UI
Location:	near Sabashahr - Iran
Phase:	En route
Nature:	Passenger - Scheduled
Departure airport:	Tehran-Imam Khomeini International Airport (IKA/OIIE)
Destination airport:	Kiev-Borispol Airport (KBP/UKBB)
Investigating agency:	AAIB Iran
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Ukraine International Airlines flight 752, a Boeing 737-800, crashed near Sabashahr, 7 minutes after takeoff from Tehran Imam Khomeini International Airport, Iran. Al 167 passengers and nine crew members on board were killed.
The Boeing 737-800, registration UR-PSR, had landed on schedule at 00:57 hours local time at Tehran. The return leg back to Kiev was due to depart at 05:15 local time (01:45 UTC).
In the meantime, around 02:15 hours local time in Iran, numerous ballistic missiles were fired from Iran towards U.S. bases in Iraq in response to the killing of Major General Qasem Soleimani by a United States drone strike.
As a result this military operation changed the alertness level of Iran's air defense. At approximately 04:00 the military sector informed the civil sector of the country's Airspace Control that only the flights already detected and cleared for flight operations by the defense network could be permitted to start up. This would ensure the correct identification of civil flights by the defense network and avoiding targeting them by mistake.
At 05:49 the doors were closed and the aircraft was ready to depart. Two minutes later the flight requested the to start up the engines.
After contacting the Area Control Center, the ATC unit requested clearance for the Ukrainian flight at 05:52. The Area Control Center forwarded the request for flight PS752 to the Air Defense Coordination Center, which subsequently issued the clearance accordingly.
The aircraft then taxied to runway 29R and commenced the takeoff roll at 06:11. After takeoff the flight contacted Mehrabad Radar and was cleared to climb to FL260 and turn right after reaching 6000 feet, heading direct to the PAROT reporting point.
As the aircraft was climbing after departure, it appeared on the air defense system. However, a wrong initialisation procedure of the system's north alignment had induced a 107-degree error in the system. Thus, the direction of objects and targets detected by this system was being observed with an increase of 107 degrees by the operator.
At 06:13:56, the air defense unit operator detected a target at his 250-degree azimuth, flying on a 52-degree course. At the same time, PS752 had been flying towards the defense system from a 143-degree azimuth. The aircraft was flying a 309-degree course.
At 06:14:21, the operator notified the specifications of the detected target to the Coordination Center over the communication network. The notification was not communicated successfully.
Meanwhile the system operator began analyzing the observable information and categorized the detected target as a threat. At 06:14:41, without receiving any response from the Coordination Center, the air defense unit operator fired a missile at the threatening target he had detected.
Under the applicable procedures, if the defense system operator cannot establish communication with the Coordination Center and does not receive the fire command, they are not authorized to fire.
The missile radio fuse was activated at 06:14:59. At that point flight PS752 was at 8100 feet at a position about 20 km west-northwest of the airport.
After the first missile radio fuse was activated, the air defense unit radar still locked on the target, and the defense system kept detecting and tracking it. By observing the continuity of trajectory of detected target, the second missile was fired at the aircraft by the operator of defense system at 06:15:11.
At 06:45:24, the last communication between the missile and the defense system was recorded in a place close to the aircraft route. After that, the defense system showed a message indicating the strike had failed, with the aircraft clearing from the radar lock-on after some time.
The aircraft turned to the right and about 06:16:11, a fire broke out on the aircraft, which was intensifying. Altitude was lost and at 06:18:23, the aircraft crashed into a playground in Khalajabad near Shahedshahr area, 15 km north of the airport. It disintegrated completely and wreckage was strewn along a 300 m long path.

Cause of the Accident
The air defense's launching two surface-to-air missiles at the flight PS752, UR-PSR aircraft the detonation of the first missile warhead in proximity of the aircraft caused damage to the aircraft systems and the intensification of damage led the aircraft to crash into the ground and explode instantly.

Other Contributing Factors
- The mitigating measures and defense layers in risk management proved to be ineffective due to the occurrence of an unanticipated error in threat identifications, and ultimately failed to protect the flight safety against the threats caused by the alertness of defense forces.

METAR:

02:44 UTC / local time:
OIIE 080200Z 28006KT CAVOK M01 / M04 Q1021

Accident investigation: