Mysore/Mysuru: Dr. N.R. Keshavan (78), retired Research Scientist and Chief of the Department, Helicopter Division, Hindustan Aeronautics Limited (HAL), Bengaluru and a resident of Chamarajapuram, passed away on Feb. 3 in city. Son of late N.G. Ramakrishna Iyengar, Dr. Keshavan leaves behind his wife Malini, son Chethan and a host of relatives and friends. Last…