India's air safety watchdog has called for urgent upgrades at air traffic control towers across international airports following a serious incident at the Delhi airport last year. The recommendation comes after an Ariana Afghan Airlines flight from Kabul mistakenly landed on an unassigned runway.
The Incident: A Landing on the Wrong Strip
On November 23, an Ariana Afghan Airlines Airbus A310, operating as flight AFG311 from Kabul, was cleared to land on runway 29L (Left) at Delhi's Indira Gandhi International (IGI) Airport. The air traffic control (ATC) instruction was correctly read back by the pilots. However, at a distance of just two nautical miles from touchdown, the aircraft deviated and touched down on the parallel runway 29R (Right) at 12:06 PM.
This occurred even as an Air India flight, AI 2243, was departing from runway 29R. The runways, designated for segregated use, were operating in a dependent mode where 29L was for arrivals and 29R for departures, making the incident a significant breach of procedure.
Investigation Hurdles and Key Recommendations
In its preliminary report, the Aircraft Accident Investigation Bureau (AAIB) faced a major obstacle. The cockpit voice recorder (CVR) data from the involved flight was overwritten because the aircraft operated its next flight to Kabul as AFG312 later that same day at 3:42 PM without the data being downloaded at Delhi.
While the digital flight data recorder (DFDR) from the 34-year-old aircraft was retrieved and its analysis is ongoing, the loss of CVR data highlighted a critical gap. To prevent such issues in future probes, the AAIB has made a pivotal recommendation.
The bureau has urged that ATC units "be equipped with devices to record video and background communications of controllers performing ATC duties in the tower." It emphasized that this installation needs "to be implemented for all international airports on priority."
Purpose and Airport Layout Context
The AAIB clarified that the purpose of such recordings would be to "analyse the controller's actions post incident/accident" and that this information would be used "solely for investigation purposes" by the Directorate General of Civil Aviation (DGCA) and the AAIB itself.
The incident underscores the challenges at Delhi's IGI Airport, which has a complex runway layout. The airport's southern runway system consists of the parallel runways 11L/29R and 11R/29L, separated by only 360 meters. This distance does not meet the criteria for independent parallel operations, necessitating the "segregated dependent mode" of operation where simultaneous landings and takeoffs are not permitted like at some other major international airports.
The investigation continues, with crew statements from both the arriving and departing flights obtained as witness records. The AAIB's recommendation now puts the focus on enhancing transparency and data availability in the nation's ATC towers to bolster aviation safety.
