Near Miss At 36,000 Feet: How A Misinterpretation Of ATC Message By Turkish Airlines Crew Led To A Mid-Air Scare With Flydubai Aircraft In Mumbai's Airspace

Mumbai: The Aircraft Accident Investigation Bureau (AAIB) has ordered Turkish Airlines to rigorously reinforce its cockpit communication protocols following a serious airprox incident over the Mumbai Flight Information Region (FIR). The order is seen as a major safety directive for international carriers operating in Indian airspace.

Near-miss investigation findings

The final investigation report into the near-miss revealed that a Turkish Airlines cargo aircraft initiated an unauthorised altitude climb by misinterpreting an electronic communication message, bringing it within a critical 1,000-feet vertical proximity of a Flydubai passenger jet. The incident involved a Turkish Airlines Cargo Airbus A330-200F, registered as TC-JOO, and a Flydubai Boeing 737 MAX 9, registered as A6-FKR, both operating at adjacent flight levels (FL) in the busy oceanic airspace managed by Mumbai Air Traffic Control (ATC).

According to the AAIB findings, the Turkish Airlines aircraft requested clearance to climb from FL340 (34,000 feet) to FL 360 (36,000 feet) using the Controller Pilot Data Link Communications (CPDLC) – a text-based data link system designed to replace traditional voice radio over oceanic routes. However, a critical misinterpretation of the subsequent digital message occurred. The flight crew erroneously executed the climb instruction without having received formal clearance.

Critical proximity & collision avoidance alert

As the heavy Turkish Airbus freighter began its unauthorised ascent, it directly encroached upon the airspace of the Flydubai Boeing 737 MAX, which was cruising safely just 3 nautical miles ahead and slightly offset to the right. The vertical separation between the two airliners rapidly degraded to less than 1,000 feet, violating mandatory safe separation standards. The sudden close proximity triggered a traffic advisory through the onboard traffic collision avoidance system in both cockpits, alerting the crews to the immediate traffic conflict.

Recognising the anomaly, the Turkish Airlines crew attempted to use voice radio communications to verify their climb clearance. While the first radio attempt went unanswered due to frequency congestion, a second call connected with Mumbai ATC. Controllers immediately informed the crew that no such climb had been approved and issued urgent, explicit instructions for the Turkish aircraft to arrest its climb and reduce speed to restore a safe buffer.

Primary probable cause identified

The AAIB final report identified the primary probable cause of the serious incident as the flight crew’s failure to accurately verify and understand the CPDLC message content before taking manual control of the aircraft’s altitude. The investigative body has issued formal safety recommendations to Turkish Airlines, directing the flag carrier to tighten its CPDLC procedures and update its standard flight operations manuals.

The AAIB emphasised that airlines must mandate a stricter cross-check and verify protocol between cockpit crew members before acting on text-based air traffic instructions, ensuring that no altitude changes are ever initiated on ambiguous or unconfirmed data link exchanges. It also suggested the Airport Authority of India’s air navigation service provider conduct recurrent training for controllers on the risks of sending stand-alone CPDLC uplink messages in reply to aircraft requests.

To get details on exclusive and budget-friendly property deals in Mumbai & surrounding regions, do visit: https://budgetproperties.in/