Exact numbers are difficult to estimate , but approximately one in a thousand sport main parachute openings malfunction , requiring the use of the reserve parachute .
Some skydivers have many thousands of jumps and never needed to use their reserve parachute .
Exact numbers are difficult to estimate , but approximately one in a thousand sport main parachute openings malfunction , requiring the use of the reserve parachute , although some skydivers have many thousands of jumps and never needed to use their reserve parachute .