What happened
On August 8, 2015, a temporary flight restriction was in effect over a field near the Istra Reservoir, specifically near the settlement of Lechish and the Istra district. This restriction, active from 09:00 to 24:00 local time, had been implemented at the request of the flight manager of the "FFT" ultralight aviation club to ensure safety for paraglider operations in the Class G airspace.
Earlier that day, at 13:38, an R-44 helicopter, registration RA-04383, landed at a private landing strip located near the owner's residence in Lechishchevo, arriving from the Zalesye landing site. This landing had been coordinated with the paragliding club's flight manager.
At 13:47, a Cessna U206F, registration RA-67523, departed from the Shevlino landing site. The floatplane began flying over the waters of the Istra Reservoir without obtaining prior coordination or establishing communication with the paragliding club's flight manager.
At approximately 17:02, the R-44 departed from the private landing strip, heading southeast toward the reservoir. The helicopter was carrying the pilot and 3 passengers. The pilot intended to perform a sightseeing flight before returning to the departure site.