On June 17, 1997, a PZL-Mielec AN-2 (registration RA-84700) operated by Tula Air Enterprise - Tulskoe Aviapredpriatie was involved in an aviation accident near Tula, Russia during takeoff. 4 people were killed. Investigators recorded the probable cause as: Engine failure as a result of the destruction of the bushing of the crankshaft of the main connecting rod due to a manufacturing defect in the absence of adhesion of bronze to the steel base of the bushing on a sufficiently large section; an unused… This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A).
After takeoff from Tula Airport, an engine failure during a turn caused the aircraft to lose speed and height, strike power cables, and crash. The captain and three passengers were killed; three others injured. The aircraft was destroyed.
Accident
Shortly after takeoff from Tula Airport, while climbing, the flight crew observed an increase in engine oil temperature and a drop in engine pressure. The captain decided to return to Tula Airport for an emergency landing. During the turn, the engine failed. The aircraft lost speed and height, struck power cables, and crashed. The captain and three passengers were killed, and three other occupants were injured. The aircraft was destroyed.
Probable Cause
According to the official investigation, the probable cause involved several factors:
Engine failure resulting from the destruction of the crankshaft bushing of the main connecting rod due to a manufacturing defect, specifically the absence of adhesion of bronze to the steel base of the bushing over a sufficiently large section.
An unused chip-in-oil signaling system, because the engine was not equipped with a chip signaling filter during repair, which deprived the crew of information about the beginning of the sleeve collapse and did not allow a timely decision to return to the departure point.
Difficult terrain with the presence of various obstacles.