The harmonisation of operating manuals across all Tata group airlines has been completed in the run-up to the Vistara-Air India merger and amalgamation of AIX Connect with Air India Express, a statement said on Monday.

At present, the steel-to-software conglomerate fully owns three airlines -- Air India, Air India Express and AIX Connect (formerly AirAsia India) -- while it holds a majority of 51 per cent in Vistara.

Singapore Airlines holds the remaining 49 per cent in Vistara.

Following the completion of the harmonisation of the operating manuals, Air India said there will be two separate manuals, one for the full-service carrier Air India and the other for the low-cost cost-carrier Air India Express.

Before this, all four airlines had separate operating manuals.

Over the last 18 months, a team of more than 100 members have worked to align on the best practices and adopt common operating procedures, Air India noted.

"This is an important milestone in the merger of the Tata Group airlines," Air India Managing Director and Chief Executive Officer Campbell Wilson said.

Air India and group companies are now initiating the necessary crew training to action the harmonised processes, the statement said.

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