Republic of Yakutia (Sakha)

It is believed that the double engine failure is the consequence of a fuel exhaustion.

Controlled flight into terrain after the crew continued to fly under VFR mode in IMC conditions.
The following contributing factors were identified:
- Unreasonable flight decision taken by the flight crew,
- The forecasted weather on the declared route did not ensure compliance with ATC,
- Failure of the pilot-in-command to take timely measures to return to the departure airfield or to take other actions to change the flight plan.

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).

The accident was the result of the destruction of the right main landing gear strut upon landing.
The following contributing factors were identified:
- Unsatisfactory performance of the welded joint in the manufacture of the strut with the formation of welding cracks in one of the most stressed zones of the strut,
- Pilot errors, which led to an early landing of the aircraft, possibly rough, on an unprepared (uncleared) area with possible obstacles.

The cause of the aviation accident with the RRJ 95B RA-89011 aircraft when landing at night with one deactivated thrust reverser was the transfer to the crew of incorrect information about the value of the friction coefficient, which led to the landing on an icy runway, the average normative friction coefficient which was less than 0.3, which did not allow landing in accordance with current regulations. This led to a significant increase in landing distance, rolling the aircraft out of the runway and collision with the junction of the reconstructed section of the runway with a height of about 0.4 m, which led to the destruction of the main landing gear supports and damage to the engines with fuel leakage without causing a fire.
The contributing factors were the following:
- Absence of a connecting ramp (which was not envisaged by the reconstruction project) between the current and the part of the runway being reconstructed;
- inefficiency of the SMS of Yakutsk Airport JSC in terms of identification and control of risks associated with the possibility of ice formation at the runway, and insufficient control over the implementation of the SMS by aviation authorities;
- erroneous determination of the Xc value at the last measurement;
- inefficiency of ice removal procedure during runway cleaning due to lack of chemical reagents for ice removal and/or thermal machines at the airfield;
- lack of information from the RRJ-95LR-100 RA 89038 aircraft crew about actual rolling out of the runway, which was an aviation incident and was subject to investigation;
- failure by airport and ATC officials to take appropriate action after receiving the RRJ-95LR-100 RA-89038 low friction report from the aircraft crew.

The accident was caused by the combination of the following factors:
- Absence of standard operating procedures issued by the operator of how to conduct NDB approaches,
- Violation of procedures by tower who only transmitted information about snow fall and recommended to perform a low pass over the runway but did not transmit the actual visibility was 1900 meters below required minimum
- Absence of information that the visibility was below required minimum, the last transmission indicated minimum visibility was present,
- Presence of numerous landmarks (abandoned ships, ship cranes, fuel transshipment complex, ...) covered by snow within 700-1000 meters from the unpaved runway which could be taken as runway markers by flight crew,
- Presence of a number of "bald spots" due to the transitional period of year where the underlying surface became visible making it difficult to visualize and recognize the unpaved runway covered with snow (it was the first flight into Belaya Gora for the crew in the winter season, they had operated into the aerodrome only in summer so far),
- Insufficient use of the available nav aid on final approach which led to lack of proper control of the aircraft position relative to the glide path,
- Lack of possibility for tower to watch the aircraft performing the NDB approach from his work place.

The accident with An-2Т RA-01419 aircraft was caused by emergency landing at the landing place in marsh area selected from air that resulted in main landing gear dipping in soft ground, dynamic pitch-down moment followed by engine ground impact and fuselage separation along engine mounting fitting, airframe structure and gear damage. Gasoline pipeline destruction during engine separation from aircraft frame and gasoline ingestion on the hot parts of power unit caused fire which almost completely destroyed the aircraft. Wrong PIC's actions who didn't turn off ignition and shut off fuel before aircraft landing could contribute to the fire. The emergency landing at the landing place selected from air was caused by oil temperature increase and pressure drop below specified by the aircraft FOM values in flight. It wasn't possible to determine the cause of temperature increase and oil pressure drop due to engine component substantial damage during fire.

The non-fatal accident with An-26B RA-26061 aircraft was caused by its RWY overrun that resulted in aircraft structure damage. The accident was possible due to combination of the following factors:
- Pilot's error resulted in approach procedure correction up to the moment of landing resulted in offset approach towards unpaved RWY axis and considerably to the left from its axis;
- Non-compliance of unpaved RWY of "Deputatsky" Airport" condition with Civil aerodrome operation manual requirements RF-94, in part of interface between cleaned and uncleaned surface of unpaved RWY with slope no more than 1:10;
- Nose-left moment during main landing gear movement along interface from recent snow up to 30-50 cm as a result of both left landing gear wheels dipping into snow.