Kolkata, Dec 8 (PTI) Former Indian Air Force Chief Air Marshal (retd) Arup Raha said the untimely death of Chief of Defence Staff (CDS) General Bipin Rawat in a helicopter crash on Wednesday is a loss for the armed forces and the whole country, and it will take some time to replace him.Gen Rawat, his wife and 11 others were killed in a Mi-17V5 chopper crash near Coonoor in Tamil Nadu. Raha, who was the Chief of Air Staff from December 31, 2013, to December 31, 2016, said the Mi-17V5 helicopters are very reliable machines but things can go wrong despite all the precautions. "It is a sad occasion. It"s a loss for the armed forces and the whole country," Raha told PTI. He said it will take some time to get a new CDS in place of Gen Rawat who was the first to hold the job in India. "It"s a new job, new task. He was doing quite well in terms of implementing all the changes that had to be ushered in as the CDS.... It is setback for us for some time but I am sure (the responsibility) will be picked up quickly by his successor," Raha said. Asked what aspects should be looked into during the inquiry into the crash, he said, "Accident is an accident... especially in the field of aviation, military aviation, things can go wrong despite all the precautions." He said since aviation is slightly risky, the risk levels are brought down by having skilled aircrew, ground crew and having good discipline, following standard operating procedure and maturity. He said accidents can still happen because "we are flying a machine which could pack up despite having been certified ok and behaving normally, but suddenly something can go wrong." Maintaining that things may also go wrong with a vehicle on the road or a ship in the sea, he said in case of an aircraft it is tricky since it is difficult to retrieve the situation. "In this case, it was flying over hilly areas in Coonoor in the Nilgiris and in hilly areas, if you have any problem with an aircraft, it is very difficult to put it down like you could have done on the plains because you have lot of open spaces or paddy fields," he said. He said when a plane or a helicopter crashlands in the hills, there would be much more damage and injuries as has happened in this case. "I am not sure how it has happened, most probably it would have been technical malfunctioning," he said. Raha, who was also a former chairman of the Chiefs of Staff Committee, said the medium lift Mi-17V5 helicopter, which was carrying the CDS, is quite safe record-wise. "IAF has a very large number of the medium lift helicopters which is the backbone or workhorse of the helicopter fleet, supporting the Army, taking soldiers and their supplies in the Himalayas and remote areas," he said, holding that it is "very reliable since it has twin engines and V5 is the latest version of Mi-17s." He said most probably something had gone wrong and that the court of inquiry will establish that. "Record-wise, th-s aircraft is quite safe, it has done a wonderful job," he said, reminding of the hundreds of sorties that several Mi-17s and Mi-5s had done during the Uttarakhand flash floods in 2013 in one of the IAF"s biggest rescue operations. Though there was an accident owing to the very inclement weather then, he said helicopters were used for flying in constricted space, high altitude, poor weather during the rescue operation and these machines performed well. "I don"t think weather is a problem here, but technical problems can always be there," he said. PTI AMR NN NN