Air India Delhi-SF flight returned due to TCAS fault on aircraft grounded for 6 years
Air India flight returned due to TCAS fault on 6-year grounded plane

An Air India flight from Delhi to San Francisco that returned to the national capital after remaining airborne for nearly nine hours on Wednesday was the same aircraft that had been grounded at Nagpur's aircraft maintenance, repair and overhaul (MRO) facility for six years due to a shortage of spares, sources said.

Aircraft History

The Boeing 777 aircraft, registered VT-ALL and named 'Goa', arrived at Air India Engineering Services Limited's (AIESL) MRO in February 2020 for routine maintenance and was expected to be cleared within a month. However, the aircraft remained stuck at the facility until March 2026 as critical components were removed and used in other aircraft requiring urgent repairs. VT-ALL itself had to wait for fresh spares for more than half a decade.

It has been learnt that VT-ALL has already operated around 100 flights after it flew from Nagpur MRO and was grounded again at Delhi.

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Incident Details

On Wednesday, as it took off from Delhi, the plane was forced to turn back when its Traffic Collision Avoidance System (TCAS) malfunctioned, said sources. TCAS allows planes to communicate with each other when they get too close, which helps in preventing collisions, according to sources.

According to sources, TCAS was among the systems inspected during the aircraft's overhaul at Nagpur MRO. The system comprises multiple components, including antennae, transponders and line replacement units (LRUs). Nearly all major components of VT-ALL, including both engines and landing gear systems, were replaced during the extended maintenance period. TCAS is part of the aircraft's avionics suite, and the aircraft can return to service once the fault is rectified, a source involved in aircraft maintenance said.

The aircraft was initially deployed on domestic sectors before being used for international routes.

Air India Statement

In a statement, Air India said the flight returned to Delhi due to a technical issue. The aircraft landed safely and will undergo a detailed technical investigation. It remained grounded at Delhi airport at the time of filing the report.

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