History of the Flight
On 29 November 2018, Saudi Arabian Airlines flight SVA9431, an Airbus A332 with registration TC-OCN, was operating from Jeddah (OEJN) to Multan (OPMT) at flight level (FL) 370 on route R471. ATC Karachi (ACC Radar North) cleared the aircraft to descend to FL350 due to crossing traffic: Oman Air flight OMA261, a Boeing 738 (A40BM), en route from Muscat to Lucknow at FL370, converging at Rahim Yar Khan. Additionally, Pakistan International Airlines flight PIA303, a Boeing 777 (APBMH), was at FL360 on route J112 from Lahore to Karachi. At 07:11:04, SVA9431 was instructed to leave FL370 for FL350.
Sequence of Events
At 07:11:26, ATC passed traffic information regarding Air Blue flight ABQ201, an Airbus A320 (VNA650), at FL340 on route J112 from Islamabad to Karachi, 12 o'clock and 20 nautical miles (NM) away. At 07:11:54 and again at 07:12:08, ATC instructed SVA9431 to expedite the descent to FL350. As SVA9431 descended, its distance from ABQ201 decreased, and its inertial vertical rate increased, reaching -3008 feet per minute at 07:12:35. At 07:12:55, SVA9431 crossed ABQ201 while climbing through FL356. At 07:13:07, SVA9431 reported a TCAS climb to FL357 and then returning to FL350. During the return descent, SVA9431 infringed the minimum standard horizontal separation of 15 NM from PIA303, with distances as low as 8.8 NM.
Outcome
No injuries or damage to any aircraft were reported. Both flights continued to their destinations. SVA9431 landed at Multan after being handed over to Multan Approach/Tower control at 07:32:52. The incident was recorded in the daily IOU report and investigated by the Safety Investigation Board (SIB) of Pakistan.