What happened
On November 29, 2015, at approximately 04:00, a crew consisting of a pilot-in-command and a second pilot-in-command arrived at the "Poligon SKOL" landing site. The mission was part of a commercial transport contract for RITEC JSC. The crew began pre-flight preparations at 04:25 and underwent medical examinations at 04:30, which showed no health concerns.
Following a review of the flight plan and receiving updated NOTAMs and refueling confirmations for Khanty-Mansiysk, the crew prepared for departure. The pilot received weather forecasts for the Surgut and Khanty-Mansiysk areas at 05:11, which did not indicate any impediments to the flight. The aircraft, an AS-350 B3 with registration RA-04037, was inspected by the crew at 05:24, with no technical issues noted in the logbook.
The helicopter departed from the Skol Polygon site at 05:40. At the time of takeoff, the aircraft's weight was 1939 kg, which was within the maximum takeoff weight limit of 2250 kg for the AS-350 B3. The center of gravity was recorded at 3.404m, also within the permitted range of 3.2m to 3.65m. At 06:15, the pilot reported transitioning from the Surgut control zone into the Khanty-Mansiysk control zone.