Incident Overview
On 3 April 2018, Airblue flight ABQ 211, an Airbus A320 aircraft with registration VN-A650, was operating a scheduled passenger flight from Dubai International Airport, Dubai, to Benazir Bhutto International Airport (BBIAP), Islamabad. The flight followed route PG–G325–HANGU–J139–FATEH–OPRN.
Flight and ATC Communication
While approaching position HANGU, the flight contacted Cherat Approach and was initially cleared to descend to Flight Level (FL) 150. Subsequently, when ABQ 211 was 40 nautical miles (NM) west of position FATEH and passing FL180, it was re-cleared to FL160 by Cherat Approach.
TCAS Resolution Advisory
At 05:31:02 UTC, while ABQ 211 was 30 NM west of FATEH and descending through FL166, the aircraft's Traffic Collision Avoidance System (TCAS) issued a Resolution Advisory (RA) due to nearby traffic. The traffic was a formation of two fighter aircraft from the Pakistan Air Force (PAF) Base Minhas to Pindi Gheb, crossing Air Traffic Services (ATS) route J139 from north to south at FL140. At 05:31:22 UTC, the Mode C transponder of the second fighter indicated a climb to FL148, which triggered the RA. In response, ABQ 211 initiated a climb to FL173.
Separation
At the time of the RA, the minimum vertical separation between the two aircraft was approximately 1,800 feet. The fighters crossed the path of ABQ 211 while the airliner was at FL173 and the military aircraft (No. 2 of the formation) maintained FL148.
Aftermath
No injuries were reported to any persons on board ABQ 211, and no damage was reported to either aircraft. There was no significant weather, and all navigation and communication aids at BBIAP were functioning normally. After landing, the flight crew submitted an Air Traffic Incident Report (Near Collision) at Islamabad Airport. The PAF formation proceeded with its mission profile, and ABQ 211 continued to its destination without further incident.