As many as 56 military aircraft have crashed in the last three-and-a-half years — a rate of more than one aircraft a month — defence minister A.K. Antony told the Lok Sabha today.A total of 34 service personnel were killed in these crashes.Of the aircraft, 37 were planes and 19 helicopters, the minister said. tony, however, did not give a breakdown to Parliament. But it was understood that the aircraft were from all the three armed forces and the coast guard. “The major reasons for aircraft accidents in the defence forces are human errors and technical defects,” Antony said.