The Indian Navy has pressed a flotilla of vessels including a submarine to locate the missing AN-32 which went off the radar two days ago over the Pay of Bengal just half hour after taking off from Chennai.
"A large number ships, helicopters and aircraft are contributing to the search," said Flag Officer Commanding-in-Chief of the Eastern Naval Command, Vice Admiral H.C.S. Bisht.
"We are also seeking ISRO's help to get satellite imagery of that area so that we have at least some information... Parallelly we are also reaching out to families," Bisht said.
An experienced pilot of the Indian defence forces told IANS: "Normally it would take a week for the debris to float in such cases. But search and rescue operations have to be carried out."
According to him, if the plane broke into several parts, then there may be a possibility of some debris floating.
But if it falls into the sea without breaking, then it may take nearly a week for some items to come to the surface from the sea depth.
"As per our calculations the sea depth in the area of search is around 3,500 metres," T.M. Balakrishnan Nair, Head, Information Services Group, Indian National Centre for Ocean Information Services (INCOIS), told IANS over phone from Hyderabad.
He said the organisation was running models estimating the distance to where the plane debris would have been carried by the sea current.
"In the Bay of Bengal there are several whirlpools that may have dragged down the debris," he added.
Defence Minister Manohar Parrikar, after reviewing the search and rescue operations on Saturday, had asked the commanding officers to keep in touch with families of those on board the missing aircraft.
Bisht said the search has been made difficult by the monsoon weather conditions over the sea.
"The only challenge we are facing is of monsoon condition, rough seas; another challenge is the depth which is around 3,500 meters and at some points even more than that," he said.
The cloud base is low and it is raining continuously in the area, he said.
"We are continuously searching the area. As of now we have 12 ships. We will be increasing the assets. We are also doing regular aerial surveillance. The aim is to harness as many resources as possible."
The missing aircraft, an upgraded AN-32 belonging to 33 Squadron, took off from Tambaram Air Force Station in Chennai at 8.30 a.m. and was expected to land at Port Blair in the Andaman and Nicobar Islands at 11.30 a.m.
The recorded transcript of Chennai air traffic radar showed the last pickup of the aircraft was 151 nautical miles east of Chennai when it was observed to have carried out a left turn with rapid loss of height from 23,000 feet.
The AN-32 is a twin engine turboprop, medium tactical transport aircraft of Russian origin. It can carry a maximum load of around 6.7 tonnes or 39 paratroopers. Its maximum cruise speed is 530 kmph.