New Delhi: Air India said on Tuesday that it expects to complete the upgrade of its 27 legacy A320 neo aircraft by mid-2025, after which all its narrow-body aircraft will have the three-class configuration of business, premium economy and economy seats.

Under the $400 million overhaul program that began on Monday, the Tata Group-owned airline will upgrade all 67 legacy narrow- and wide-body aircraft, including 40 Boeing aircraft.

The upgrade began with the single-aisle A320 neo aircraft and, following prototyping and necessary regulatory approvals, the VT-EXN aircraft is expected to re-enter commercial service in December 2024.

"After VT-EXN, three to four aircraft will be modernized per month, with an upgrade of the entire narrowbody fleet expected by mid-2025," the airline said in a statement.

Overhaul of the first wide-body aircraft will begin in early 2025, subject to supply chains. The airline's legacy widebody fleet comprises B787 and B777 aircraft.

The retrofit project will be coordinated by Air India's engineering team with leading global OEMs (Original Equipment Manufacturers) such as Collins, Astronics and Thales. The exercise will include the installation of more than 15,000 next-generation seats in business, premium economy and economy classes, the statement said.

Passengers have complained about some service issues with the airline's legacy fleet, including those related to inflight entertainment systems.

According to the airline, the refurbished A320 neo aircraft will have 8 business class seats, 24 premium economy class seats and 132 economy class seats. Among other facilities, these aircraft will have supports for portable electronic devices and USB ports.

Air India said final preparations continue for complete interior upgrade of all 40 legacy wide-body aircraft.

"The commencement of the interior refurbishment of the narrowbody fleet is an important step in our path to improve the flying experience of our customers. Over time, all legacy widebody aircraft will also be refurbished," said CEO and CEO of Air India. Campbell Wilson said.

Currently, Air India has a fleet of 142 aircraft, including around 60 wide-body aircraft. The fleet also includes 11 B 777 aircraft and 25 leased A320 family aircraft.

After taking over loss-making Air India in January 2022, Tata Group has drawn up a transformation roadmap for the airline, which is now expanding its fleet and network. The airline has also started operating wide-body A350 aircraft on several routes.