How 'Loss of Situational Awareness' Brought AirAsia, IndiGo Flights Within 8 km, Reveals New Report

Aug. 24—Two flights over Mumbai airspace came within 8 km of each other when their altitude separation was just 300 feet, according to an Aircraft Accident Investigation Bureau (AAIB) report released earlier this month. AirAsia India's Ahmedabad-Chennai flight and IndiGo's Bengaluru-Vadodara flight were involved in this "serious incident" which, as per the report, happened due to the air traffic controller's "loss of situational awareness", reported news agency PTI.

The evaluation of the situation by the controller at the Mumbai airport "under the influence of preconceived mind" has been cited as another probable cause behind the incident.

"The minimum separation between both the aircraft was recorded as 8 km laterally while (it was) 300 feet vertical(ly) when the AirAsia India flight was below the IndiGo flight and it was 6.5 km laterally when the vertical separation was 500 feet when IndiGo flight was below the AirAsia India flight," the report said.

Most of the flights from Ahmedabad to southern India overfly Bhavnagar but the AirAsia flight was on a route usually taken by planes descending to land at the Mumbai airport, the report explained. The changed route of AirAsia flight and direct routing of the IndiGo flight coming from the opposite direction resulted in the heading of both flights becoming "reciprocal to each other" at different altitudes.

The automation system of the air traffic controller issued a "predicted conflict warning" when there was enough lateral separation between the two flights. But the controller at the Mumbai airport ignored the "predicted conflict warning", presuming the AirAsia flight was on its usual route, according to the report. By the time the controller realised the situation, the AirAsia India flight was at 38,008 feet and the IndiGo flight at 38,000 feet.

AirAsia flight's traffic collision avoidance system (TCAS) issued a warning to the pilots, prompting them to continue the plane's ascent. As the IndiGo flight maintained an altitude of 38,000 feet, the conflicting traffic was resolved when the AirAsia flight reached an altitude of 38,396 feet, according to the report.

(With PTI inputs)

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