Accident Antonov An-2R RA-33036,

ASN Wikibase Occurrence # 319829

Date:	Saturday 26 August 2017
Time:	17:50
Type:	Antonov An-2R
Owner/operator:	Aviakompaniya Feniks
Registration:	RA-33036
MSN:	1G218-23
Year of manufacture:	1986
Total airframe hrs:	4754 hours
Cycles:	12934 flights
Engine model:	Shvetsov ASh-62IR
Fatalities:	Fatalities: 0 / Occupants: 2
Aircraft damage:	Substantial, written off
Category:	Accident
Location:	75 km W of Yeniseisk, Krasnoyarsk Territory - Russia
Phase:	En route
Nature:	Agricultural
Departure airport:	Yeniseisk Airport
Destination airport:
Investigating agency:	MAK
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
The Antonov 2R biplane operated on aero-chemical flight over the Yenisei Forest in Russia.
On the fortieth minute of the flight along the route there appeared smoke of the cockpit of medium intensity. The captain decided to terminate the task and return.
After 30 km of flight the smoke intensity increased significantly. The crew heard blows in the area of the engine, after which vibrations were felt, accompanied by a loss of power. Oil was seen flowing onto the windows and wings. The engine did not respond to the propeller pitch and thrust movement. The captain then decided to make a forced landing in the forest.
During the landing, the aircraft collided with trees and the ground surface, resulting in significant damage to the aircraft. The crew members suffered minor injuries.

Conclusion (translated from Russian):
The cause of the aviation accident with the AN-2 RA-33036 aircraft was the decrease of power of the ASh-62 IR engine due to fatigue failure of cylinder No. 5.
Fatigue failure of the cylinder occurred due to a manufacturing defect - no blunting of sharp edges at the Ø 12 mm bore for the stud bolt of the sleeve to the crankcase in the most loaded zone.
Probable factor contributing to the failure could be the irregularity of the cylinder flanges and engine crankcase in the specified area.

Accident investigation: