Russia

The accident of the An-28 aircraft, registration RA-28728, occurred during a forced landing on an improvised landing site due to the simultaneous shutdown of both engines while in flight. The need for this landing was triggered by the engines' spontaneous shutdown. The shutdown occurred while the aircraft was flying in icing conditions with the Pitot-Static System (POSS) turned off due to ice ingestion into its air intake.
The aviation incident was most likely influenced by the following factors:
- The crew's failure to follow the Aircraft Flight Manual (AFM) procedures for manually activating the POSS when meteorological conditions favored icing;
- Violation of the crew's duty and rest time regulations, which could have led to the accumulation of operational fatigue and contributed to missing the operation to activate the POSS;
- The crew's failure to make the decision to cease further performance of their duties due to the accumulation of operational fatigue in the absence of the airline's established procedures for exercising this crew right, which does not comply with the provisions of the Russian Ministry of Transport Order No. 139 dated November 21, 2005, "On Approval of the Regulation on Features of the Work and Rest Time Regime for Crew Members of Civil Aviation Aircraft in the Russian Federation";
- Increased hypoxia stress when flying at altitudes exceeding 3000 meters without the additional use of oxygen, which is a violation of the regulations of FAP-128, AFM, and the airline's internal regulations, and could have exacerbated the negative effects of operational fatigue;
- A malfunction in the ice detection sensor DSL-40T, which prevented the issuance of ice detection alerts and the automatic activation of the POSS.

The cause of the An-26B-100 RA-26085 aircraft crash was the crew's violation of the established instrument approach procedure to Palana aerodrome, which was manifested in flying with significant deviation from the set route and descent well below the established minimum descent height (MDH) under weather conditions that excluded stable visual contact with ground landmarks, leading to the collision of the aircraft with a coastal cliff in controlled flight, its destruction, and the death of the crew and passengers.
The following contributing factors were identified:
- The crew's failure to execute a missed approach with the acquisition of the established minimum safety altitude (MSA) when information about the bearing indicated a significant deviation of the aircraft from the established approach procedure;
- The absence in the Palana aerodrome dispatcher's work technology of actions in the presence of information about the bearing indicating a significant deviation of the aircraft from the established approach scheme, as well as the dispatcher's passivity when such information was available;
- The lack of warning signals from the early ground proximity warning system under conditions that should have triggered it. It is not possible to determine the reason for the absence of the warning signals;
- The overestimation of the barometric altimeter readings in the final phase of the flight due to the specific airflow around the steep coastline creating a low-pressure zone and the overestimation of the variometer readings, the cause of which cannot be determined.

Failure of the high pressure compressor disk on the engine n°2 during the takeoff procedure.

The accident with the An-2 RA-71276 aircraft occurred as a result of a collision with a mountain at an altitude of 2,780 metres above sea level perpendicular to the direction of the ridge with its minimum height of 2,960 metres conditions of limited visibility and the closure of mountain tops by clouds.
The following contributing factors were identified:
- The crew took the decision to perform a flight over a mountainous area with predicted closure of the mountains by clouds and unfavorable wind conditions,
- The crew took the decision to return to the landing site through the mountain range along an unexplored and previously unused route,
- Operational fatigue of the crew due to the significant duration of working hours on the day of the accident (more than 12 hours),
- The airplane falling under the influence of descending air currents on the leeward side of a mountain slope.

The cause of the accident with the An-2 RA-40851 aircraft was the collision of the aircraft with a reinforced concrete support and power transmission lines in a controlled flight while performing the aerial application at an extremely low altitude.
The contributing factors most likely were:
- Field processing when the sun is less than 15° above the horizon and the sun's heading angle is less than 30°,
- Insufficient prudence of the PIC when performing a VFR flight for aerial application,
- Failure of the pilot to take into account the presence of artificial obstacles in the flight area,
- Lack of marking of power lines.

The aircraft stalled during initial climb because its total weight was above the MTOW and the CofG was well beyond the aft limit. The crew failed to prepare the flight according to procedure and, failed to proceed with a mass and balance calculation and the passengers and lugages were incorrectly placed in the cabin according to the CofG.

The accident with the Boeing 737-500 VQ-BPS aircraft occurred during the landing as a result of a collision of the aircraft with a snow parapet 1.1 m high at a distance of 32 m to the runway threshold (within the paved section of the runway), which resulted in damage to the main landing gear and their subsequent "folding" in the process of moving along the runway.
The accident was caused by a combination of the following factors:
- the presence of contradictions in the Federal Aviation Rules for flights in the airspace of the Russian Federation, the airline's radio control system and the aircraft operational documentation regarding the need and procedure for introducing temperature corrections to the readings of barometric altimeters at low ambient temperatures;
- Failure by the operator of the Usinsk aerodrome to comply with the FAP-262 requirements for the maintenance of the aerodrome, which resulted in the presence of snow parapets on the paved section of the landing strip;
- the operator of the Usinsk aerodrome did not eliminate the shortcomings in the winter maintenance of the aerodrome, noted based on the results of the inspection by the Rosaviatsia commission on January 22, 2020;
- lack of risk assessment in the airline associated with the execution of approaches in the baro-VNAV mode in the presence of factors that impede such approaches (low ambient temperatures, snow-covered underlying surface, drifting snow (snowstorm), significant changes in the relief in front of the runway end, lack of PAPI-type lights), as well as appropriate recommendations to the crews on the specifics of such approaches, including after the transition to visual flight, and crew training;
- insufficient assessment by the crew during the preparation of the existing threats (hazard factors) and making an insufficiently substantiated decision to perform an RNAV (GNSS) approach (under the control of the autopilot in LNAV/VNAV mode) without introducing a correction for low outside air temperature in altitude overflying waypoints, which led to a flight below the established glide path;
- performing a flight along the "extended glide path" after turning off the autopilot and switching to manual piloting without attempting to enter the set glide path;
- the PIC may have had a visual illusion of a "high glide path" due to a snow-covered underlying surface, a snowstorm and the presence of a ravine directly in front of the runway end in the absence of PAPI type lights, which led to an incorrect assessment of the aircraft's flight altitude after switching to manual piloting, lack of reaction to timely and correct warnings of the co-pilot and exit to the runway end at a height significantly less than the established one.

The accident was caused by the fact that the PIC did not maintain a safe flight altitude in mountainous terrain, which led to the aircraft getting into strong downdrafts while flying over the leeward side of the ridge, uncontrolled descent and collision with the top of the mountain.
The contributing factors of AP, most likely, were:
- insufficient analysis of meteorological conditions and the possibility of the formation of strong ascending and descending air currents in the mountains;
- Failure of the PIC to take safety measures when flying in the mountains and to act in case of falling into downward air currents when crossing a mountain ridge;
- the use of motor gasoline with an octane rating of less than 95, which led to a decrease in engine power;
- performing a mission on the An-2 aircraft without the procedure for restoring skills and admission to flights on this type after a significant break in flights (about 15 years).