Accident Tupolev Tu-154M RA-85185,

ASN Wikibase Occurrence # 322115

Date:	Tuesday 22 August 2006
Time:	15:39
Type:	Tupolev Tu-154M
Owner/operator:	Pulkovo Aviation Enterprise
Registration:	RA-85185
MSN:	91A894
Year of manufacture:	1991
Total airframe hrs:	24215 hours
Engine model:	Soloviev D-30KU-154-II
Fatalities:	Fatalities: 170 / Occupants: 170
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	45 km NW of Donetsk - Ukraine
Phase:	En route
Nature:	Passenger - Scheduled
Departure airport:	Anapa Airport (AAQ/URKA)
Destination airport:	Saint Petersburg-Pulkovo Airport (LED/ULLI)
Investigating agency:	MAK
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Pulkovo flight 612 departed Anapa (AAQ) for St. Petersburg (LED) at 15:05. The Tu-154M climbed to the cruise altitude of 35,100 feet (10.700 m). Because of storm cells ahead, the pilot decided to change course laterally by 20 km and attempted to climb over the storm cells. However, the thunderstorm front was unusually high, extending up to 15 km (49,000 feet). The Tu-154 entered an area of severe turbulence, pushing up the airplane from 11.961 m to 12.794 m within just 10 seconds. The angle of attack increased to 46 degrees and the airspeed dropped to zero. It entered a deep stall from which the crew could not recover. The plane crashed and burned in a field.

The cause of the crash was the loss of control in the manual flight mode with supercritical angles of attack, causing a stall with the subsequent transition to a flat spin and collision with the ground with a large vertical velocity. Factors were considered poor crew coordination, and failure to follow the instructions in the Aeroplane Flight Manual to prevent a stall. Also, the crew training methods used were insufficient to demonstrate the dangers of manual flight at high altitudes.

Accident investigation: