An Indonesian Navy ship sails near what appears to be oil slicks during the search for submarine KRI Nanggala that went missing while participating in a training exercise on April 21, in this aerial photo taken from a maritime patrol aircraft of 800 Air Squadron of the 2nd Air Wing of Naval Aviation Center (PUSPENERBAL) over the Bali Sea, Indonesia, April 23, 2021. (ERIC IRENG/AP)

BALI / BANYUWANGI - Indonesian searchers have recovered debris believed to be from the missing submarine lost in the Bali Sea on Wednesday, the country’s military chief said on Saturday.

The Indonesian navy chief of staff said a scan had detected the submarine at 850 meters, well beyond its survivable limits. The submarine, which disappeared as it prepared to conduct a torpedo drill, is designed to withstand a depth of up to 500 meters.

The United States is deploying a P-8 Poseidon aircraft to assist in the search and rescue operation for the Indonesian navy submarine, as hopes fade for the 53 crew which are expected to have run out of oxygen early on Saturday.

READ MORE: Desperate hunt for Indonesian sub as oxygen set to run out

The Indonesia navy lost contact with the 44-year-old KRI Nanggala-402 submarine on Wednesday as it prepared to conduct a torpedo drill.

Australia has also deployed a sonar-equipped frigate with a helicopter to help the submarine hunt, while a deep submergence rescue vessel is on route from India, as concerns grow that the submarine might have been crushed by water pressure

Australia has also deployed a sonar-equipped frigate with a helicopter to help the submarine hunt, while a deep submergence rescue vessel is on route from India, as concerns grow that the submarine might have been crushed by water pressure.

“The possibility of it having fallen underneath its maximum diving depth thereby leading to the implosion of the submarine will have to be considered,” said Collin Koh, Research Fellow at the Institute of Defence and Strategic Studies.

If the submarine was still intact, Indonesian officials said on Friday it would only have enough air to last until around dawn on Saturday if equipment was functioning properly.

ALSO READ: Indonesian navy: Missing sub has enough oxygen for 72 hours

Koh said the assumption that the submarine had 72 hours of oxygen was optimistic given the submarine’s limited ability to generate oxygen due to its conventional power generation.

“So there’s a possibility...oxygen might have already run out,” said Koh.

Indonesia’s navy said it was investigating whether the submarine lost power during a dive and could not carry out emergency procedures as it descended to a depth of 600-700 meters, well beyond its survivable limits.

Visitors stand next to a static display of the US Navy aircraft the Poseidon P-8 on the tarmac during the Singapore Airshow in Singapore on Feb 11, 2020. (ROSLAN RAHMAN / AFP)

The Bali Sea can reach depths of more than 1,500 meters.

One of the people on board was the commander of the Indonesian submarine fleet, Harry Setiawan.

Late on Friday, the Pentagon said US Defense Secretary Lloyd Austin had spoken with his Indonesian counterpart Prabowo Subianto and offered additional support, which could include undersea search assets.