Authorities in the Sverdlovsk region have called off the search for the An-2 light aircraft that went missing in June.
Regional government chief Denis Pasler signed the order calling off the search operation because of deteriorating weather conditions on Tuesday.
The order ends a search effort that has seen aircraft and volunteers scour almost 300,000 square kilometers for any trace of the aircraft and its 13 passengers but has been plagued by false leads.
The An-2 biplane has not been seen since it took off without permission from an airfield near the Sverdlovsk region town of Serov on June 11.
On board were pilot Khtip Kashapov and 12 passengers, including the town's traffic police chief Dmitry Ushakov and his deputy Maxim Mayevsky.
Early on, investigators suggested that the passengers may have been on a drunken fishing or hunting trip, with empty spirit bottles found at the aerodrome pointing to high spirits and a possible explanation for a crash.
A search of the Sverdlovsk region and parts of the neighboring Udmurtia republic and Perm and Tyumen regions found the wreckage of another An-2 and fragments of a Mi-8 helicopter, but no sign of the plane that took off from Serov.
It was also dogged by false leads. A man thought to be a survivor of the crash turned out to be a former convict who had lost touch with his relatives.
And when relatives of the missing passengers arrived at the location of a "satellite" photo that surfaced online and appeared to show the outline of a plane, they found only empty countryside.
A trawl of a reservoir thought a likely crash site found nothing, and the airborne search was initially called off in July.
Authorities renewed their efforts in September after a radio hobbyist claimed to have picked up distress signals from the missing aircraft saying that "two policemen are dead" and stating "death from starvation."
The local Emergency Situations Ministry took the lead seriously but was unable to locate the missing crew.
The disappearance has drawn comparisons to the Dyatlov Pass Incident, when nine hikers mysteriously died in the northern Urals in 1959.