Army helicopter carrying senior defence officials, including chief of defence staff Bipin Rawat, crashed at Coonoor in Nilgiris district in Tamil Nadu on Wednesday. The status of the fliers is not yet known. According to reports, around four senior defence officials were on board. Three officials have been rescued so far while a search is on for the fourth person, an official said. The injured have been taken to Wellington cantonment in Nilgiris.  News report said  Bipin Rawat, his staff and some family members were in the Mi-series chopper. As soon as the chopper crashed, a search and rescue operation was launched from nearby bases, sources confirmed.