New Delhi: : The closure of Pakistani airspace over Karachi’s Jinnah International Airport in May played a critical role in a serious incident involving two international flights arriving from Muscat to Mumbai, by significantly increasing air traffic in this sector.
A coordination failure at Muscat Airport due to increased workload, coupled with delayed action by the controller at Mumbai Operations Control Centre, were the primary causes of the serious incident on May 4, according to the final investigation report.
The Aircraft Accident Investigation Bureau (AAIB) on Thursday released its report on the serious Airprox (loss of longitudinal separation) that occurred at 2:30 am at Chhatrapati Shivaji Maharaj International Airport, involving UAE’s Air Arabia flight ABY405 from Sharjah carrying 166 passengers, and German cargo carrier AeroLogic’s BOX622 from Frankfurt with two crew members on board.
A Notice to Airmen (NOTAM) issued by Pakistan from April 24 to May 23 restricted all Indian civil and military flights, leading to a significant increase in traffic density in the region. “This increased the workload for both Muscat and Mumbai controllers,” the report stated.
Providing details of the incident, the AAIB said the point of conflict was the waypoint PARAR, which lies on the boundary of the Flight Information Region (FIR) between Mumbai and Muscat. There was only a three-minute interval between the two aircraft, instead of the mandatory 10-minute separation required, the report noted.
The flight paths of both aircraft converged at a waypoint (VAXIM), from where they continued on the same route segment. Between this waypoint and PARAR, both aircraft were under the control of Muscat Control – Sector Alpha. They were subsequently handed over to Mumbai Operations Control Centre via the High Frequency Communication System, the report added.
“The Mumbai Operations Control Centre (North) issued vectors to BOX622 to laterally offset the aircraft and subsequently initiated a level change, ensuring safe separation from preceding, succeeding, and reciprocal traffic in the vicinity,” it said.
The transferring controller in Muscat was also providing on-the-job training to a trainee at the time, which impacted his performance and situational awareness. At the same time, the coordinator in Mumbai was unavailable, forcing the controller to handle both roles while also busy exchanging estimates on the hotline. “This resulted in the accepting controller monitoring the airprox situation late,” the report elaborated.
No flight level change was entered into the Air Arabia flight’s planner list, which meant it remained at the previously coordinated level, and no conflict warning was generated. “The controller later realized the conflict and resolved the traffic by directing BOX622 to deviate and subsequently descend to flight level 310 (from FL350),” the report said. Additionally, the filed flight plan was stuck in an error queue, which further prevented any alerts from being triggered.
The AAIB has recommended that all Air Traffic Control positions be adequately staffed to ensure the Executive Controller can focus solely on traffic management without distractions. It also advised that instructors should not be assigned dual roles during operations to maintain safety standards.
