CHENNAI: Even as Defence Minister Manohar Parrikar claimed there were small unverifiable leads from the missing IAF aircraft AN-32, search and rescue operations failed to yield any results on Tuesday. “We have detected 4-5 pings, and are trying to verify whether these are real or false alarms,” media reports quoted Parrikar as having said in the Rajya Sabha. Meanwhile, the focus on the fifth day was on how to carry out the search at a depth of 3,500 metres.
Marred by rough seas and no exact location of where the aircraft went down, the search is being conducted by extrapolating the time of the crash and the only hope is to catch the signals emanating from the flight decoder recorder, which is feared to be under the sea at a depth of 3,500 metres. Sources are hoping this could be achieved by National Institute of Ocean Technology research vessel ‘Sagarnidhi’, as it has the most advanced sonar, multi-beam echo sounder. While the sonar of the Indian submarines can’t come handy at such a depth, it is learnt Sagarnidhi’s multi-beam echo sounder could travel up to 6,000 metres depth. Like other sonar systems, multi-beam systems emit sound waves in a fan shape beneath a ship’s hull. The amount of time taken for the sound waves to bounce off the seabed and return to a receiver is used to determine water depth.
Besides that, the ship also has sub-bottom profiler that scans the seabed for anything protruding above it. Indian National Centre for Ocean Information Sciences (INCOIS) director Satheesh Chandra Shenoi, who holds the additional charge of NIOT director, said it is the only option left with the team conducting search and rescue operation. Shenoi said the technology was used during the hunt for Coast Guard’s missing Dornier.
The issue with the search operation is that the depth of the sea where the aircraft went missing has not been mapped as it is the case with Exclusive Economic Zone. Across the world less than five per cent of oceans have been mapped. Shenoi said mapping of oceans is a costly exercise which could be done if only there is a need. According to him, it won’t be an easy task for Sagarnidhi and the resolution which it will get while conducting the search operation won’t be that clear.