Investigation Summary
The investigation by the Interstate Aviation Committee (MAK) revealed a series of procedural lapses and environmental factors. Despite being warned by the controller not to descend over the sea, the crew performed a turn that took them over the water and into a zone of low visibility. The crew reported being at 1200 meters when they were actually at 1650 meters, yet they continued to descend rapidly. A critical factor was the aerodynamic overestimation of the barometric altimeters: as the aircraft approached the steep coastline, the specific airflow created a local low pressure zone, causing the altimeters to indicate the aircraft was higher than its true altitude. Furthermore, the Ground Proximity Warning System (GPWS) failed to provide any alerts before the impact, for reasons that could not be determined.
Final Conclusions
The primary cause was the crew's violation of the established approach procedure, characterized by a significant lateral deviation from the flight path and descent below the Minimum Descent Height (MDH) without visual contact with the ground. Contributing factors included the controller's passivity in failing to warn the crew of their observed deviation, the failure of the GPWS to trigger, and the barometric altimeter errors caused by local coastal topography.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Systems & Failure Modes
Barometric Altimeter
The device provided over-readings due to a low-pressure zone created by airflow over the steep coastal terrain.
GPWS
The Ground Proximity Warning System failed to alert the crew of the impending terrain collision.
NDB
The Non-Directional Beacon at the airport was used for the initial approach phase before the crew deviated.
Interesting Facts
- 01The aircraft was a 39-year-old Antonov An-26 originally built for military use and converted for civilian passengers in 2012.
- 02The same flight number (251) and route were involved in a previous fatal crash in 2012 involving an Antonov An-28.
- 03One of the passengers was Olga Mokhiriova, the head of the Palana municipal government.
- 04The wreckage was found on a cliff edge, with parts of the aircraft falling into the Sea of Okhotsk.
- 05The investigation found that the Ground Proximity Warning System (GPWS) did not emit any warning signals prior to impact.
Safety Actions & Advisories
ATC Procedural Review
The report highlighted the need for dispatchers to take active measures when radar or bearing information shows a significant deviation from established approach schemes.