There is no stepping down of search operations for the missing AN-32 plane belonging to Indian Air Force with 29 people on board on July 22 despite no signs of debris or oil slick on the sea surface, said a senior Indian Coast Guard official on Sunday.

"Whether it is Coast Guard or Indian Navy or IAF, the search operations have not been slowed or stepped down even though no debris of the missing plane or oil slick was found on the sea," the official, who did not want to be named, told IANS.

He said now hopes are pinned on the the Sagar Nidhi vessel belonging to National Institute of Ocean Technology (NIOT) that is expected to join search operations soon.

The ship has the capacity to search under water and is expected to join search operations on August 2 or 3.

The plane with 29 people on board went missing shortly after taking off from Chennai for Port Blair. The recorded transcript of air traffic radar showed the last pick up of the aircraft was 151 nautical miles east of Chennai when it took a left turn with rapid loss of height from 23,000 feet.