Argentine submarine latest: Hope for missing crew dwindles as ‘seven-day oxygen supply likely runs out’

The search for a missing Argentine submarine with a crew of 44 has entered a “critical phase”, authorities have said, as the seven-day oxygen supply was due to run out today.

The ARA San Juan went missing on 15 November while it was travelling from the extreme southern port of Ushuaia to the city of Mar del Plata, about 250 miles southeast of Buenos Aires.

The last known communications with the submarine were two calls - one to report a routine battery fault, while the other call has not been disclosed by the Argentine Navy.

The loss of the submarine has sparked an international rescue effort, but powerful storms with waves of over 20 feet (six metres) have hampered efforts to find the craft.

Authorities still do not know if the submarine rose to the surface to replenish oxygen and charge batteries, but it is thought it is unlikely to have surfaced without then being located.

If underwater, then assuming the hull remains intact, estimates for how long the air supply could last range from between seven to 10 days.

“We are in the critical phase...particularly with respect to oxygen,” Argentine navy spokesman Enrique Balbi said on Wednesday.

“There has been no contact with anything that could be the San Juan submarine.”

Capt. Balbi, added: “The seven days is not dogmatic. It varies according to the circumstances. As a submariner, I am not losing hope.”

Hopes were briefly buoyed after satellite calls were apparently received and when sounds were detected deep in the South Atlantic.

However it was later discovered neither was from the missing sub.

Later a US Navy aircraft spotted flares, and a life raft was found in the search area, but authorities said they did not come from the missing submarine.

The false alarms have caused further distress for the crew’s family members. As the search enters a critical phase, some have begun to complain that the Argentine navy responded too late.

“They took two days to accept help because they minimized the situation,” Federico Ibanez, the brother of 36-year-old submarine crew member Cristian Ibanez, told the Associated Press.

The navy has said the submarine reported a battery failure before it went missing as it journeyed to the navy base in Mar del Plata. Authorities have no specific details of the problem.

“I feel like authorities let too much time pass by and decisions were taken late,” Ibanez's sister, Elena Alfaro, said outside the base. “And yet, I still carry some hope.”

The German-built diesel-electric TR-1700 class submarine was due to arrive at the naval base in Mar del Plata on Monday.

Local residents have arrived at the base carrying blue-and-white Argentine flags and bringing messages of support for relatives of the crew anxiously waiting for news.

Associated Press contributed to this report