He flew 46 sorties over the reactor building, for a combined total duration of 52 hours. The most important of those sorties was the so-called "Operation Igla" (Operation Needle), the June 19, 1986 installation of a giant -long radiation probe on top of the building by means of a precision drop from a Kamov coaxial rotor helicopter.
He executed 46 sorties over the reactor complex for a cumulative flight time of 52 hours. The most critical mission was 'Operation Igla' (or 'Operation Needle'), a June 19, 1986, operation that involved deploying a long radiation probe on top of the building via precision helicopter drop.