A deep sea search for the Indian Air Force aircraft AN-32 will begin late on Sunday evening in Bay of Bengal, as an ocean research vessel prepared to scan through the seabed.
AN-32 transport aircraft went missing mid-air with 29 people onboard on July 22, about 15 minutes after it took off from Tambaram Air Force base to Port Blair.
Speaking to the Times of India, NIOT director Satheesh C Shenoi said that the deep sea search would begin around 169 miles off the Chennai coast.
“We are diverting Sagar Nidhi directly to the search location and she is expected to reach any time after 2pm. She has to search an area of 220 nautical miles, which may even begin in the night," TOI quotes Shenoi as saying.
The missing AN 32 aircraft, which had flown multiple times over the Bay of Bengal carrying military personnel and equipment, did not have an underwater locator system, making it difficult for rescuers to pinpoint the position of the plane.
In fact, none of the upgraded AN32 aircraft, the main workhorse of the military, has an underwater locator, unlike the modern transport planes like C130J or C17.
The missing aircraft came with two Emergency Locator Transmitter (ELT) -- a stationary ARTEX C406-1 ELT manufactured by ACR Electronics/Artex Products, the US, and a French-made portable KANNAD 406AS ELT manufactured by Orolia
In an emergency, the pilot has to activate the ELT beacon manually. The integrated ELT gets activated when the impact is about 2.3 G or 4.5 feet per second
However, ELT would not get activated automatically since radio waves are not transmitted in the water. There is no signal from ELT under water for this reason, IAF sources said
The sources said trials were already on to procure underwater ELTs for the aircraft and, as an emergency measure, effort is to have some kind of an underwater ELT on any aircraft that flies over water
Also, the AN-32 aircraft does not have the Automatic Dependent Surveillance - Broadcast
This system relies on navigational satellites to automatically transmit an aircraft's journey in real time and it can be switched on and off based on operational needs
Defence Minister Manohar Parrikar had said overdue action, as per the Standard Operating Procedures, started at 1230 hours, one hour after the scheduled arrival at Port Blair and nearly three-and-a-half hours after the plane went out of ground radar cover area
It was only at 1225 hours that Maritime Rescue and Coordination Centre, Chennai reported that an IAF AN-32 (AF-330) was not in contact. The weather at the time when the plane went missing was overcast with multi-layered clouds and embedded convection
The pilot had asked for deviation to the right to avoid a thundershower cloud before disappearing.
Inputs PTI