History of the Flight
On 5 March 2024, Saudia Airlines flight SVA792, an Airbus A330-343 (registration HZ-AQ18), operated a scheduled passenger flight from King Khalid International Airport (OERK), Riyadh, to Bacha Khan International Airport (OPPS), Peshawar. At 035230 UTC, the aircraft contacted Peshawar Tower at FL160 while proceeding to TOMON via the HANGU 1D arrival. The civil controller re-cleared the aircraft via the HANGU 1C arrival for an ILS Z approach to Runway 35 and instructed the pilot to report overhead PS VOR for holding due to ongoing military flying.
At 035700, traffic information was issued regarding military aircraft operating at FL140 and below overhead PS. The expected approach time of 0430 was given at 035732. At 035900, SVA792 reported 10 NM short of PS on radial 219 and was instructed to join the standard holding pattern overhead PS VOR, maintaining FL160. At 035950, the aircraft was cleared to descend and maintain FL140.
At 041344, SVA792 was informed about an emergency landing of a military aircraft at PS and was advised to stand by for a revised EAT. Due to this emergency, Runway 35 at PS was blocked, and all military aircraft were advised to fly for endurance and hold overhead PS VOR. Meanwhile, a military aircraft (MA1) recovering from a routine training mission was cleared to FL160 and directed to hold over OPPS VOR.
While holding, MA1, flying with minimum power for endurance, inadvertently lost altitude and descended to FL147, triggering a Traffic Advisory (TA) followed by a Resolution Advisory (RA) for SVA792. At 042300, SVA792 reported the TA and initiated an RA descent from FL140 to 13,500 ft due to MA1 turning ahead with less than 1,000 ft vertical separation. The civil controller passed traffic information about military flying at FL160 and 12,000 ft, along with a revised EAT of 0450. After clearing the conflict, SVA792 climbed back to FL140. The flight crew reported observing the conflicting traffic on a head-on trajectory descending through their level.
At 042943, the civil controller informed SVA792 about another military aircraft descending from FL160 to 10,000 ft, 15 NM north of OPPS. SVA792 later reported a second TA due to a military aircraft crossing its inbound course to PS at approximately 1,500 ft above, subsequently descending to 500 ft below and 2 NM ahead.
Contributing Factors
Peshawar Airport is a joint-user airfield with civil and military controllers operating from a shared control tower. The airspace is limited, catering for both types of traffic. According to the investigation report, this limitation combined with the blocked runway emergency, which led to aircraft flying for endurance, resulted in the TCAS-RA serious incident. The incident was noted as a safety concern for both aircraft and passengers on board.