Near-miss over Arabian Sea ‘exposes’ ATC failures

A potential mid-air disaster over the Arabian Sea was narrowly averted earlier this year, but what the investigation has since uncovered is far more chilling than the incident itself. A series of cascading failures within India’s Air Traffic Control (ATC) system, from missing hotline recordings and faulty automation to ignored logbooks and undefined duties, almost allowed two international flights come dangerously close to each other thousands of feet above the ocean.

According to the final report by the Aircraft Accident Investigation Bureau (AAIB), the incident occurred around 2.30 am on May 4 when an Air Arabia passenger flight from Sharjah and an AeroLogic cargo jet from Frankfurt came close to each other after entering the Indian airspace at the same altitude.

The Air Arabia flight ABY405, carrying 166 persons, and AeroLogic flight BOX622, with two crew members, both crossed the waypoint ‘PARAR’, the boundary between Muscat and Mumbai airspace, separated by just three minutes. The required gap at that altitude is 10 minutes.

Investigators found that the Muscat controllers had failed to take the Air Arabia flight to a higher level before the handover. At the same time, the Mumbai controller, who should have been monitoring the incoming traffic, was busy handling calls on the hotline “in the absence of a dedicated coordinator”. This meant that the lapse went unnoticed until the planes were too close.

What followed was a scramble to avert disaster. The Mumbai controller quickly issued turning and descent instructions to the faster AeroLogic cargo jet to create space between the two aircraft. Fortunately, the move worked, and both flights continued safely to Mumbai.

However, the probe has revealed flaws in the system. Despite all radar and communication systems working normally, no automated conflict alert was triggered in Mumbai’s Oceanic Control Centre (OCC). The report said the flight plan of the AeroLogic jet “may not have been present in the system” as it was stuck in an error queue, meaning the software never recognised the aircraft. This prevented the system from warning controllers about the risk.

Even more troubling, the AAIB found that the recordings of the hotline conversations between Mumbai and Muscat, were missing. The report said the recording system was down because of an ongoing replacement of the EPABX facility at the Mumbai ATC complex.

The probe also flagged that the logbooks, where controllers are required to record all key handovers and communication details, were not properly maintained. It said “the taking over in the logbook is not executed meticulously,” even though separate logbooks had been provided for each sector. Investigators noted that the duties of the coordinator, a critical support position, “are not defined” in the existing manual for en-route operations.

The findings are alarming as the Directorate General of Civil Aviation (DGCA) had issued a circular reminding ATC personnel across India to maintain updated logbooks and communication records without fail.

At the time of the incident, the coordinator at the Mumbai OCC had taken a break, leaving the main controller to handle the hotline, monitor radar screens and process flight progress strips. “The controller did not observe the conflict either on the flight progress strips or on the system display,” the report said.

The AAIB blamed ATC units for “coordination failure” and “delayed action”, saying these directly led to the loss of required separation. It also cited “non-generation of conflict alert in both ATC units” and “unavailability of hotline recordings” as key contributing factors.

To prevent similar incidents, the AAIB recommended that the AAI separate hotlines for each waypoint, split the operational workload between positions handling automation and put in place a backup system to record calls whenever the main recording facility is down.