New Delhi, Jan 7 (PTI) Aircraft Accident Investigation Bureau (AAIB), in a probe report into an airprox incident involving two IndiGo planes, has recommended that aviation regulator DGCA carry out an inspection to assess the effectiveness of airlines' safety management systems.

In its 35-page final investigation report into the incident that happened in the Delhi airspace on November 17, 2023, the probe agency said that non-adherence to the Standard Operating Procedures (SOP) by the crew of one of the flights was one of the probable reasons for the incident, while the airline's failure to take timely action despite repeated SID-related occurences prior to the particular incident was a contributing factor.

Generally, airprox refers to two aircraft coming closer than the permitted distance between them, and Standard Instrument Departure Route (SID) pertains to the route that an aircraft takes from the take-off to the enroute phase.

IndiGo's A321 aircraft operating flight IGO2113 from Delhi to Hyderabad and A320 plane operating the flight IGO2206 from Delhi to Raipur were involved in the serious airprox incident.

Apart from non-adherence to SOP by the crew of IGO2113 during cockpit preparation and failure to update the SID when it was provided, AAIB cited inadequate measures taken to minimise disturbances during cockpit preparation, failure to cross-verify the SID information during the TPC (Threats-Plan-Considerations) briefing, and the lack of monitoring during the climb as probable causes.

Making various recommendations in the final report, AAIB has said the Directorate General of Civil Aviation (DGCA) may carry out a one-time inspection to assess the effectiveness of the safety management system of all the scheduled operators and air navigation service provider as well as reiterate the rules to ensure compliance with prompt reporting of mandatory occurrences without fail.

The recommendations also come in the context of AAIB's detailed examination of the occurrence data provided by the Airports Authority of India (AAI), which indicated six previous SID-deviation events involving IndGo aircraft that had happened within a four-month period from August 2023 to November 2023.

"Scrutiny of the occurrence and safety reports of IndiGo, along with the technical logbooks for the involved aircraft, showed that no PDR entries were recorded for any of the above SID deviations.

PDR refers to Pilot Defect Report.

The report noted that the two events were not reported by the operating flight crews to IndiGo, and these occurrences were brought to the airline's attention through an email from AAI. Also, both incidents were not reported by IndiGo to DGCA or AAIB.

Other AAIB recommendations in the report include that AAI may conduct a study on unjustified STCA (Short Term Conflict Alert) and on other ANSPs conducting high-intensity simultaneous parallel departures, in order to identify possible shortcomings in airspace design and ATC (Air Traffic Control) procedures.

Besides, the report said IndiGo has taken corrective action with respect to reiterating the importance of completing aircraft set-up before conducting briefings, ensuring correct FMGS (Flight Management and Guidance System) entry, avoiding disturbances during cockpit preparation, and carry out comprehensive cross-checks during training activities. PTI RAM HVA