The AIP could get installed on the second of the Kalvari class as and when it comes in for its normal refit, the sources said.
Last December, the defence ministry signed a Rs 1,990 crore contract with Mazagon Dock Shipbuilders Limited (MDL) for the construction of the AIP plug and its integration into the Kalvari class of submarines.
Interestingly, the normal refit is likely to be carried out by the Naval Dockyard Mumbai rather than by the MDL, which had manufactured the submarines in conjunction with French firm Naval Group, earlier known as DCNS.