Synopsis
On 2 June 2021, Gulf Air flight GFA 770, a Boeing 787-9 aircraft registered as A9C-FF, was operating a scheduled flight from Bahrain International Airport to Islamabad International Airport. Weather in the Islamabad area and surrounding regions was reported as thunderstorms with rain. After passing HANGU, the flight deviated left of track due to severe weather. When the aircraft was 15 nautical miles northwest of KALMI, it was cleared to descend to 5,000 feet at the pilot’s request due to weather conditions. As the aircraft descended through 5,300 feet, the pilot reported climbing to 7,000 feet and subsequently to 10,000 feet because of a Ground Proximity Warning System (GPWS) warning just short of position KALMI. GFA 770 then held for 1 hour 50 minutes for weather improvement before landing at Islamabad International Airport. All times are in Coordinated Universal Time (UTC).
History of the Flight
At 22:52:00 UTC, GFA 770 contacted Area Control Islamabad while approaching position LAKRA, descending from Flight Level 290. The aircraft was identified and given an arrival clearance with descent to FL150. The expected arrival time was 23:12 UTC.
At 22:57:15 UTC, approaching south of HANGU, the aircraft requested to maintain heading 060° for 10 nautical miles to avoid inclement weather. The Area Radar Controller approved the weather deviation. Weather at that time was thunderstorms and rain at Islamabad and surrounding areas.
At 23:01:14 UTC, GFA 770 requested further descent. Area Control Islamabad inquired how long the heading would be maintained. GFA 770 reported turning right heading 060° and was cleared to descend to 9,000 feet on QNH 1006 hPa, which was acknowledged.
At 23:01:42 UTC, GFA 770 changed frequency to Approach Control Islamabad. At 23:02:12 UTC, the flight contacted Approach Control Islamabad crossing FL144. Subsequently, the aircraft was given a descent clearance to 5,000 feet contrary to the Area Minimum Altitude of 10,300 feet. While descending through 5,300 feet, GFA 770 received a GPWS terrain react warning, and the pilot initiated a climb to 7,000 feet, then to 10,000 feet. The aircraft then held for weather improvement before landing safely.