The search operations would move into the third phase next week and the NIOT had been requested to bring its remotely operated vehicle that can be taken to a depth of 3,500 metres, Coast Guard Commander (East) Inspector General Rajan Bargotra said in Chennai.
So far two phases -- surface search and sub-surface -- have been undertaken, but no debris of the transport aircraft that went missing on its way to Port Blair from Tambaram airbase has been found, he said.
"As of now we are into second phase of search operations. Surface search, we have already done that for quite sometime. No debris has been located. Now the focus is on sub-surface search," he said.
Noting that the search operations began with 13 ships of Coast Guard and Navy, besides IAF aircraft, he said when it was certain that there was no debris visible on the surface, the search was "tapered" down to sub-surface search.
"Initially, we almost started with 13 ships and 11 planes and after doing that for about a month or so, when it was certain that there was no debris which was visible on the surface and it was not likely to be there, then we have slowly tapered down the search," he said.