Preliminary investigations have indicated that blasts on INS Sindhurakshak submarine were caused by "possible ignition" of armament, defence minister AK Antony told the Rajya Sabha on Monday.
In wake of the incident, the Navy has ordered extensive checks on weapon-related safety systems on all its submarines, he said in a suo motu statement on the submarine accident in Mumbai last week.
The minister also pointed out that the "rapidity and intensity of the explosions and the resultant damage to the submarine indicate that the 18 personnel on board would not have survived."
"Preliminary investigations indicate that the explosion was due to the possible ignition of armament. The cause of ignition is, however, yet to be established. Forensic examination would throw more light into the possible cause of ignition," Antony said.
He said this would be possible only after the "partially submerged" submarine is afloat and dewatered. "A Board of Inquiry with all relevant specialists has been constituted to investigate the likely causes of the accident at the earliest."
After the accident, the Navy has ordered an audit of Standard operating Procedures (SOPs) on all operational submarines and extensive checks on the weapon-related safety systems, the defence minister said.
He said as the "explosion and resultant damage were near instantaneous, the 18 personnel could not evacuate. Although full details are yet to emerge, the rapidity and intensity of explosion and resultant damage sustained by the submarine indicate that the personnel would not have survived."
Antony said globally-renowned salvage agencies have been approached and they are undertaking survey for salvage operations.
"There is also an offer of help from Russia, where the refit and upgrade of the submarine had been undertaken," he said.