What happened
On 15 February 2018, Pakistan International Airlines flight PIA 585, an ATR 42-500 with registration AP-BHP, was conducting a scheduled passenger service from Dera Ghazi Khan Airport to Jinnah International Airport, Karachi. During the descent phase of the flight, the aircraft was operating at Flight Level 100.
Simultaneously, a formation of three Pakistan Air Force F-16 aircraft, flying under the call sign TIGER-1, was returning to Bholari from the Masroor Training Area. The military formation was maintaining Flight Level 80. Karachi Approach Controller had previously instructed the PIA crew to maintain Flight Level 100 to ensure separation from the military traffic and had provided timely traffic advisories.
As the aircraft progressed, radar data indicated that the military formation was approaching the airliner. At approximately 05:26:17 UTC, the crew of PIA 585 reported a Traffic Alert and Collision Avoidance System – Resolution Advisory (TCAS-RA). Following the advisory, the crew initiated a climb to Flight Level 102. The military aircraft were subsequently cleared to descend to Flight Level 50 to facilitate the airliner's descent. No injuries or damage to either aircraft were reported.