Air India is facing its biggest operational crisis since being acquired by the Tata Group three and a half years ago, with seven international flights cancelled on Tuesday and a technical snag forcing passengers on the San Francisco–Mumbai flight to deboard during a scheduled stopover in Kolkata.

An Air India flight from San Francisco to Mumbai was forced to deplane passengers early Tuesday during a scheduled stop in Kolkata after a technical issue was discovered in one of the aircraft’s engines,

Tata Group-owned Air India on Tuesday cancelled as many as 16 flights on Tuesday, mostly belonging to the airline’s Boeing 787 fleet, according to data shared by aviation regulator DGCA (Directorate General of Civil Aviation).