Investigation Summary
The accident was a result of a complex interplay between human factors, regulatory contradictions, and poor aerodrome maintenance. The crew performed an RNAV (GNSS) approach using VNAV mode in temperatures as low as -21°C. Because barometric altimeters over-read in cold air, the aircraft's actual altitude was lower than indicated. The crew did not manually apply cold temperature altitude corrections, a task complicated by conflicting guidance in Russian federal aviation rules and airline documentation. Furthermore, the Usinsk Airport operator had failed to remove 1.1-meter high snow parapets located just before the runway threshold, which had been previously flagged by inspectors. When the pilot disconnected the autopilot, a 'high glide path' visual illusion, common in flat, white-out conditions with a ravine preceding the runway, prevented him from recognizing the dangerously low approach angle. Following the investigation, the 23-year-old airframe was declared a total hull loss and retired due to the extent of the structural damage to the fuselage and wing spars.
Final Conclusions
The Interstate Aviation Committee (MAK) concluded the primary cause was the crew's decision to conduct a baro-VNAV approach without temperature corrections, leading to a flight path below the established glide path. Contributing factors included the presence of unauthorized snow parapets on the runway's paved safety section, the lack of PAPI lights at the airport, and the airline's failure to provide specific risk assessments or training for approaches in such extreme winter conditions.
Photographic Evidence (1)
Video Analysis
UTair B737 Crash Lands at Usinsk Airport in RUSSIA — Footage and details regarding the emergency landing of Utair flight 595 at Usinsk Airport where the landing gear collapsed after hitting a snow bank.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
The Captain was the Pilot Flying (PF).
First Officer
The First Officer was the Pilot Monitoring (PM).
Systems & Failure Modes
Baro-VNAV
A navigation system that uses barometric altitude to calculate a vertical path; it is sensitive to temperature errors if not corrected.
Main Landing Gear
The primary support structures which separated and folded after impacting the snow parapet.
LNAV/VNAV
Lateral and Vertical navigation modes used by the autopilot to follow a programmed flight path.
Interesting Facts
- 01The aircraft touched down 32 meters short of the runway threshold.
- 02The snow bank struck by the aircraft was 1.1 meters high and located on the paved section of the runway safety area.
- 03The outside air temperature was -21°C, which requires manual altitude correction for baro-VNAV approaches.
- 04Usinsk Airport lacked PAPI (Precision Approach Path Indicator) lights at the time of the accident.
- 05The aircraft was a 23-year-old Boeing 737-524 (WL) that was subsequently written off due to substantial structural damage.
Safety Actions & Advisories
Aerodrome Maintenance Compliance
Source ↗The investigation highlighted the need for aerodrome operators to strictly follow FAP-262 requirements regarding the removal of snow parapets from paved sections of the landing strip.
Temperature Correction Standardization
Recommendations were made to resolve contradictions in Russian Federal Aviation Rules regarding the mandatory introduction of temperature corrections for barometric altimeters.