The area of search operation for tracing the missing AN 32 transport aircraft has been expanded significantly. Addressing newspersons in Chennai on Monday evening, the Indian Coast Guard Eastern Region Inspector General Rajan Bargotra said, keeping in view of the drift in the sea, the elapsed time since the disappearance of the Indian Air Force aircraft and the inputs from the search made so far, every day the search area is being determined. With this, the aerial search has been expanded to 60-thousand square nautical miles and surface search to 14-thousand-400 square nautical miles. Mr Bargotra said, a submarine that is reaching the search area would begin its probe from tomorrow.<br/><br/>Indian Coast Guard Eastern Region Inspector General Rajan Bargotra said "Once we rule out that there is no debris available on board or we are not able to find any clue about the survivors, once we are done with it, definitely the next step would be going for the underwater search. Navy has already deployed its submarine and it will be available in the area from tomorrow onwards."<br/><br/>The weather has considerably improved over the search area in the Bay of Bengal, and satellite imageries show the sky is clear. Mr Bargotra also said, inputs from the ISRO and the Indian National Centre for Ocean Information Service have been sought. He said, a research vessel of the National Institute of Ocean Technology would also join the search operation soon. He said, so far, no clue about the survival of the personnel in the disappeared aircraft has been received and no debris traced. <br/><br/>AIR correspondent reports that the Operation Talash to look for the missing AN32 is being carried out relentlessly for the fourth day today in an expanded zone in the sea. The failure of the Emergency Locator Transmitter in the ill-fated aircraft is a dampener in locating its position precisely. The device is designed to emit e.m. radiation for the sensors to pick the signals. However, in this case, it is either not responsive or its signals are weak for detection and the matter has been taken up with the equipment manufacturer, as clarified by the Coast Guard official. Defence officials say, the search operation goes on without any fixed time frame and in strict adherence to the National Maritime Search and Rescue Manual.<br/><br/>Meanwhile Air Chief Marshal Arup Raha today said it is unfortunate that the missing aircraft and the personnel on board have not been traced. In a statement, the Indian Air Force chief said, he shared the concerns of the family members of the missing personnel. He said, IAF authorities are in constant touch with the family members and they are being regularly updated about the efforts being made to trace the missing aircraft.<br/> He backed the AN-32 aircraft saying they have excellent operational performance and added that Indian Air Force is committed to provide the best possible equipment and training to its personnel. He said, a thorough enquiry will be conducted to ascertain exactly what led to this unfortunate event.