What happened
On October 2, 2013, at approximately 09:06 UTC, a GoAir Airbus A320, registration VT-GOK, was preparing for a scheduled departure from Delhi to Mumbai. At the same time, an Indian Air Force (IAF) AN-32, registration VUDBL, had recently landed at Delhi from Chandigarh and was taxiing toward the Air Force Technical Area.
Due to a recent VVIP movement, several aircraft departures had been delayed, leading to a high density of traffic. To clear the backlog, air traffic controllers transitioned to simultaneous runway operations, which included activating Runway 09. As the GoAir flight commenced its takeoff roll, it was discovered that the IAF aircraft was cleared to cross the now-active Runway 09. Upon realizing the imminent danger, the Tower controller instructed the GoAir crew to abort. The pilot successfully rejected the takeoff at approximately 100 knots, preventing a collision.
The investigation
The investigation by AAIB India focused on the sequence of clearances and the operational environment at Delhi airport. Investigators examined the transition of control for Runway 09, which had been moved from the Surface Movement Control (SMC) North to the Tower controller. The inquiry also reviewed the communication logs between the controllers and both aircraft, as well as the workload of the SMC controller during the period of high traffic density.
Findings
- The SMC (N) controller provided clearance for the IAF aircraft to cross Runway 09 without realizing the runway had been activated for departures.
- The controller was managing heavy traffic and was simultaneously resolving conflicts between other aircraft.
- A lack of support staff meant the SMC controller had to physically move to collect flight progress strips, contributing to a loss of situational awareness.
- The active status of Runway 09 had not been updated on the ATIS broadcast, leaving the IAF crew unaware of the change in runway status.
- The IAF crew was not monitoring the SMC (N) frequency or the Tower frequency during the crossing, which prevented them from receiving the emergency instruction to hold position.
- The error chain was broken by the rapid intervention of the Tower controller and the decisive action of the GoAir pilot.
Safety action
- The investigation highlighted the need for improved infrastructural and procedural support for handling high-density traffic at Delhi airport.
- Specifically, the lack of dedicated personnel to manage flight progress strips was identified as a factor that increased controller workload and susceptibility to error.