Sajana Chandran | Sajana Chandran | TEDxThiruvananthapuram

Quick Overview

Sajana Chandran, a Joint General Manager in Air Traffic Control, recounts the terrifying near-collision of two aircraft—a Tupolev Tu-154 and an Ilyushin Il-76 cargo plane—over Ubarlingen, Germany, on July 1, 2002, which resulted in 71 fatalities, emphasizing that the accident was preventable because the primary radar system provided correct information, but the secondary system failed to relay altitude data to the incoming aircraft, leading to the tragic outcome.

Key Points: The presentation details the 2002 Ubarlingen mid-air collision between a Tupolev Tu-154 and an Ilyushin Il-76 cargo plane on July 1, 2002, which killed 71 people, including the families of both flight crews. The crash occurred because the primary radar system correctly identified the conflict, but the secondary radar system (TCAS) failed to provide the necessary altitude warning to the descending cargo plane. The primary radar in India's ATC systems provided accurate information, but the secondary radar (Transponder) did not provide the required altitude information to the incoming aircraft. The controller on duty, Peter Nielsen, was blamed, but the speaker argues that the failure lay in the less advanced primary radar system not being able to prevent the collision, despite the secondary system's failure. The speaker, having worked at Varanasi Airport, personally dealt with similar complex traffic situations and understood the gravity of relying on outdated or insufficient technology. The controller, Peter Nielsen, had only one option: turn left to avoid the initial conflict, but clouds prevented this, and turning right would have caused a collision with the descending aircraft.

Context: The speaker, Sajana Chandran, a Joint General Manager in Air Traffic Control, uses the story of the tragic 2002 Ubarlingen mid-air collision to illustrate critical failures in aviation safety systems and procedures. He frames the discussion around the concept of layered defenses in ATC, highlighting how the failure of one system (secondary radar/TCAS) combined with the limitations of another (primary radar) led to disaster, even when procedures were technically followed.