Indonesian Navy submarine On 21.04.2021 all communication was lost with Indonesian Navy submarine  KRI NANGGALA (402) Cakra-class with 53 crew, which was conducting torpedoes drill in the Bali Sea, about 20 nm (according to AIS data) from north of northern Bali island coast. An active search was started, with the deployment of Navy and SAR ships and boats. As of 13:20 UTC 21.03.2021, at the moment SAR is underway, final results unknown.
Indonesian Navy KRI NANGGALA (402) Cakra-class submarine, displacement 1390, length 60 meters, built 1981, armament torpedoes, sea endurance 50 days, trial depth 240 meters.

Source: https://www.maritimebulletin.net/2021/04/21/indonesian-navy-submarine-with-53-crew-missing-in-bali-sea/