Pakistans four AIP submarines raise concerns for Modi government, threat spreads from Arabian Sea to Indian OceanIndia on alert! Pakistan’s four AIP submarines raise concerns for Modi government, threat spreads from Arabian Sea to Indian OceanAIP systems enable diesel-electric submarines to remain submerged and operational for weeks without surfacing or using a snorkel. The Indian Navy, on the other hand, is still waiting to induct its first submarine equipped with this system. Experts are of the opinion that detecting these submarines could prove to be a tough challenge for the Indian Navy. AIP systems enable diesel-electric submarines to remain submerged and operational for weeks without surfacing or using a snorkel.