NEW DELHI/GUWAHATI: Satellites, spy aircraft, fighters, helicopters and foot soldiers are conducting a major search operation for the missing AN-32 medium transport aircraft , but are yet to find any trace of the wreckage in the densely-forested hilly terrain of Arunachal Pradesh.The search operation for the plane, which did not have modern avionics , radars or emergency locator transmitters (ELTs), is currently centered on the “probable crash zone” in the Along-Payum-Tato area. The “zone” was calculated on the basis of the last radar and radio contact by the ill-fated AN-32 with ground control units at 1 pm on Monday, close to the China border in the West Siang district of Arunachal Pradesh.Arunachal Pradesh home minister Bamang Felix said, “We have mobilised the civil and police administration of five districts. We have also appealed to the local people to join the administration in the search operation.” The area over where the aircraft is believed to have gone missing is densely forested and inaccessible. The weather is also bad. But we are hopeful of getting some news.”As the northeastern region usually remains covered with clouds, Risat satellite can easily see through clouds and scan the region to locate the plane wreckage. Risat has been picked for the search operation as the cloud-penetrating satellite can do earth observation day and night and with its X-band synethic aperture radar can zoom up to a resolution of 1 metre (means it can distinguish between two objects separated by 1 m distance) and send clear images of an object on the earth.“The reconnaissance satellite can take images of an object on the earth at least 2 to 3 times a day,” a source in Indian Space Research Organisation, on condition of anonymity, said. “However, the only obstacle for the Risat satellite is the tree canopy. The satellite can’t penetrate the canopy. However, if the plane’s wreckage is lying in an open hilly area, the satellite can locate it,” the source said. Besides the satellite, security forces have also deployed spy drones and reconnaissance aircraft of the IAF and Navy.The AN-32, which was on its way to the Mechuka advance landing ground (ALC) from the Jorhat airbase in Assam, had six officers and seven other IAF personnel on board. “There were two sets of crew, with a pilot, co-pilot and navigator each, because one of them was on a familiarisation trip of the area,” said an officer.Even as C-130J Super Hercules aircraft undertook night sorties to scan the probable crash zone, the Navy also deployed a P-8I long-range maritime reconnaissance plane for the operation on Tuesday afternoon. Both the C-130Js and P-8Is have synthetic aperture radars as well as electro-optical and infra-red sensors that can help the hunt for a plane wreckage.Speaking to media in Guwahati, defence PRO Col C Knower said, “Extensive efforts are on to locate the AN-32. Indian Air Force commenced extensive search and rescue operations and launched C-130, AN-32, Mi-17 and ALH ( Indian Army ) helicopters. Post sunset, search by helicopters have ceased for the day. However, Search by all sensors with night capability and the ground party will continue throughout the night,” the source said.He added that all possible assistance is being provided by Indian Army, Indian Navy, police and state administration. “The families of all air-warriors on board the aircraft have been informed and are being regularly updated on the progress of search for the missing aircraft,” he added.A major problem in locating the aircraft is the outdated “Sabre-8” ELT or beacon installed in the cargo compartment of the AN-32, which was yet to be upgraded with airframe strengthening, advanced avionics and radars to fly in difficult conditions, as was first reported by TOI.Only 54 of the about 100 AN-32s in the IAF fleet, which were inducted from the erstwhile Soviet Union between 1984 and 1991, have been upgraded with “total technical life extension from the original 25 years to 40 years, overhaul and re-equipment” till now under an initial $400 million contract with Ukraine in 2009.“No distress signals from the AN-32 have been detected yet. The ELTs, which have a limited battery life, get activated if the aircraft experiences an impact of 20G (20 times the force of gravity). The AN-32 upgrade project, apart from airframe strengthening, enhanced ground-warning systems, new weather radars, advanced GPS, multi-functional displays etc, also involves fitting two new modern ELTs on the twin-engine turboprop aircraft,” said another officer.But the supply of some spares, components and kits for the AN-32 upgrade project, under which the first 40 aircraft were “re-equipped” in Ukraine with the rest slated to undergo it at the Kanpur BRD (base repair depot), have been hit because of the bilateral problems between Russia and Ukraine over the Crimean Peninsula. “The upgrade project was to be completed in five years but has moved at a very slow pace,” said the officer.