Moscow oblast

The reason for the accident with the Gulfstream G200 4K-AZ88 was the stowing of the right-engine reverser by the pilot KVS from maximum thrust reversal while maintaining maximum thrust reversal on the left engine, which led to the appearance of a significant turning moment to the left. The aircraft turning to the left in the presence of a cross wind to the right, as well as turbulence of the airflow near the rudder due to the open thrust reversal mechanism of the left engine and possible ice deposition on the outer surfaces of the aircraft, which led to the development of a significant swing moment on the rudder. The development of a significant articulated moment on the rudder, in the absence of power steering in the rudder control system, led to its deviation to the leftmost position despite significant (up to 82 kg or 180 pounds) forces exerted by the crew on the pedals. The deviation of the rudder (pedals) to the left also led to the deviation of the nose wheel to the left. The total moment from the running reverse of the left engine, from the right engine in direct draft mode, and from the rudder and nose wheel deflection to the left, led to the aircraft rolling out of the runway and its damage. Separate braking applied by the crew could not prevent the aircraft from rolling out.

The following contributing factors were identified:
- The crew did not take into account the provisions of the AOM about the possible "destabilizing" effect of the thrust reverse when landing with a cross wind on the runway with a reduced braking coefficient;
- Increased psycho-emotional tension of the crew members due to long dissatisfaction and emotional discussion of instructions and actions of ATC controllers. At the same time, the instructions and actions of the ATC service controllers were in line with established procedures.

The accident was the consequence of erroneous actions on part of the crew while climbing in instrument meteorological conditions at unreliable readings of instrument speed caused by icing (blockage with ice) of all three Pitot tubes. This caused the aircraft to become uncontrollable, enter a dive and eventually collide with the ground. The accident was then considered as a loss of control in flight (LOC-I). The investigation revealed systemic weaknesses in the identification of hazards and risk control, the inoperability of the airline's flight safety management system and the lack of control over the level of training of crew members by aviation authorities at all levels, which led to the issuance of certificates of aviation personnel and the admission to the flights of the crew, which did not fully meet the qualification requirements. The following contributing factors were reported:
- Hurry of the crew in preparation for the flight due to the late arrival of the aircraft from the previous flight and attempts to "catch up" with the time,
- Skipping by the crew of the operation to switch on the Pitot tube heating before takeoff and failing to comply with the section of the check list "BEFORE TAKE-OFF", which provides for the control of this action,
- Design features of the An-148 aircraft in terms of the restrictions on the duration of Pitot tube heating operation on the ground, which led to the need to carry out operations to control the inclusion of Pitot tube heating and compliance with the principle of "dark cockpit" in a separate section of the "BEFORE THE FLIGHT" check list, which is performed immediately before the start of the takeoff run, which creates additional risks of missing these operations. These actions are provided in the section "ON THE RUNWAY START",
- Systematic failure of the airline's crews to comply with the "dark cockpit" principle and the requirements of the radar, which contributed to "getting used" to the takeoff with the presence of emergency and warning messages on the Integrated system and alarm indicator (KISS) and did not allow to identify the fact that the Pitot tube heating was not included. In the accident flight before takeoff, six warning messages were displayed on the KISS, including three messages about the absence of Pitot tube heating,
- Design features of the An-148 aircraft, connected with the impossibility to disable the display of a number of warning messages on the KISS even when performing the whole range of works provided for by the MMEL while ensuring the flight with delayed defects,
- Low safety culture in the airline, which was manifested in: systematic failure to record in the flight log the failures detected during the flight, as well as in the performance of flights with the failures not eliminated and/or not included in the list of delayed failures, accompanied by the corresponding messages on the KISS,
- Failure to take necessary measures in case of detection of previous facts of untimely activation of Pitot tube heating by crews based on the results of express analysis of flight information,
- Unreadiness of the crew to take actions in case of triggering the alarm "Speed of Emergency" due to the lack of appropriate theoretical training in the airline and the impossibility to work out this special situation on the flight simulation device and / or during airfield training and, as a consequence, failure to comply with the procedures provided for after triggering of this alarm,
- Absence of federal aviation regulations for certification of flight simulators, the development of which is provided for by the Air Code of the Russian Federation,
- Approval for the existing AN-148 flight simulators of the IFC Training LLC and the CTC of the Saint-Petersburg State University of Civil Aviation without taking into account their actual capabilities to reproduce special flight cases, as well as the provisions of FAR-128,
- Absence of specific values of flight parameters (engine operation mode, pitch and roll angles, etc.) in the aircraft's flight manual, which must be maintained by the crew of the airspeed alarm system, as well as absence of the situation with unreliable instrument speed readings (Unreliable Airspeed Procedure) in the list of special flight cases,
- Increased psycho-emotional tension of crew members at the final stage of the flight due to inability to understand the causes of speed fluctuations and, as a consequence, the captain falling under the influence of the "tunnel effect" with the formation of the dominating factor of speed control according to the "own" (left) airspeed indicator without a comprehensive assessment of flight parameters,
- Insufficient training of pilots in the field of human factor, methods of threat and error control and management of crew resources,
- Individual psychological peculiarities of pilots (for the captain - reduction of intellectual and behavioral flexibility, fixation on their own position with the inability (impossibility) to "hear" prompts from the second pilot; for the second pilot - violation of the organization and sequence of actions), which in a stressful situation in the absence of proper level of management of the crew resources came to the fore; loss of the captain's psychological performance (psychological stupor, psychological incapacitation), which resulted in complete loss of spatial orientation and did not allow reacting to correct prompts and actions of the co-pilot, including when triggering the PULL UP warning of the EGPWS system,
- Absence of psychological incapacitation criteria in the airline's AFM, which prevented the second pilot from taking more drastic measures,
- High annual leave arrears for special conditions, which could lead to fatigue and negatively affect the performance of the captain,
- Operation of the aircraft control system in the longitudinal channel in the reconfiguration mode with unreliable signals of instrument speed, not described in the operational documentation, related to a double increase in the transfer coefficient from the hand wheel to the steering wheel in the flight configuration and constant deviation of the steering wheel for diving (without deviation of the steering wheel) for about 60 seconds, which reduced the time required for the crew to recognize the situation.

The most likely cause of the crash of the An-2 RA-35171 was the failure of the PIC to pilot the An-2 aircraft at high flight speeds (an increase in the time required for the aircraft to leave the bank due to the decrease in the angles of the aileron deflection due to the pulling of the cable line due to a significant increase in forces in the transverse of the control channel at speeds of 270-300 km/h), which did not allow the aircraft to arrest the descent when maneuvering with large angles of bank at an extremely low flight altitude.
The contributing factors were:
- Piloting the aircraft at modes beyond the limits set by the AFM of the An-2 aircraft;
- Maneuvering at an altitude less than that established for performing a demonstration flight over the aerodrome.

The accident occurred at nighttime under foggy conditions while it was taking off after cleared by the controller due to collision with the snowplow that executed runway incursion and stopped on the runway. Most probably, the accident was caused by the combination of the following contributing factors:
- lack of guidance on loss of control over an airdrome vehicle and/or situational awareness on the airfield in pertinent documents defining the duties of airdrome service personnel (airdrome shift supervisor and vehicle drivers);
- insufficient efficiency of risk mitigation measures to prevent runway incursions in terms of airdrome peculiarilies that is two intersecling runways;
- lack of proper supervision from the airdrome service shift supervisor, alcohol detected in his organism, over the airfield operations: no report to the ATM or request to the snowplow driver as he lost visual contact with the snowplow;
- violation by the airdrome service shift supervisor of the procedure for airdrome vehicles operations, their entering the runway (RWY 2) out of operation (closed for takeoff and landing operations) without requesting and receiving clearance from the ground controller;
- violations by the medical personnel of Vnukovo AP of vehicle driver medical check requirements by performing formally (only exterior assessment) the mandatory medical check of drivers after the duty, which significantly increased the risk of drivers consuning alcohol during the duty. The measures and controls applied at Vnukovo Airport to mitigate the risk of airdrome drivers doing their duties under the influence of alcohol were not effective enough;
- no possibility for the snowplow drivers engaged in airfield operations (due to lack of pertinent equipment on the airdrome vehicles) to continuously listen to the radio exchange at the Departure Control frequency, which does not comply with the Interaction Procedure of the Airdrome Service with Vnukovo ATC Center.
- loss of situational awareness by the snowplow driver, alcohol detected in his organism, while perfonning airfield operations that led to runway incursion and stop on the runway in use.
His failure to contact the airdrome service shift supervisor or ATC controllers after situational awareness was lost;
- ineffective procedures that resulted in insufficiently trained personnel using the airfield surveillance and control subsystem A3000 of A-SMGCS at the Vnukovo ATC Center, for air traffic management;
- no recommendation in the SOP of ATM personnel of Vnukovo ATC Center on how to set up the airfield surveillance and control subsystem A3000, including activation and deactivation of the Reserved Lines and alerts (as a result, all alerts were de-activated at the departure controller and ground controller's working positions) as well as how to operate the system including attention allocation techniques during aircraft takeoff and actions to deal with the subsystem messages and alerts;
- the porting of the screen second input of the A3000 A-SMGCS at the ATC shift supervisor WP for the display of the weather information that is not envisaged by the operational manual of the airfield surveillance and control subsystem. When weather information is selected to be displayed the radar data and the light alerts (which were present during the accident takeoff) become un available for the specialist that occupies the ATC shift supervisor's working position;
- the ATC shift supervisor's decision to join the sectors at working positions of Ground and Departure Control without considering the actual level of personnel training and possibilities for them to use the information of the airfield surveillance and control system (the criteria for joining of sectors are not defined in the Job Description of ATC shift supervisor, in particular it does not take into account the technical impossibility to change settings of the airfield surveillance and control system);
- failure by the ground controller to comply with the SOPs, by not taking actions to prevent the incursion of RWY 2 that was closed for takeoff and landing operations by the vehicles though having radar information and alert on the screen of the airfield surveillance and control system;
- failure by the out of staff instructor controller and trainee controller (providing ATM under the supervision of the instructor controller) to detect two runway incursions by the snowplow on the runway in use, including after the aircrew had been cleared to take off (as the clearance was given, the runway was clear), provided there was pertinent radar information on the screen of the airfield surveillance and control subsystem and as a result failure to inform the crew about the obstacle on the runway;
- lack of recommendations at the time of the accident in the Operator's (Unijet) FOM for flight crews on actions when external threats appear (e.g. foreign objects on the runway) during the takeoff;
- the crew failing to take measures to reject takeoff as soon as the Captain mentioned «the car crossing the road». No decision to abort takeoff might have been caused by probable nonoptimal psycho-emotional status of the crew (the long wait for the departure at an unfamiliar airport and their desire to fly home as soon as possible), which might have made it difficult for them to assess the actual threat level as they noticed the snowplow after they had started the takeoff run;
- the design peculiarity of the Falcon 50EX aircraft (the nose wheel steering can only be controlled from the LH seat) resulting in necessity to transfer aircraft control at a high workload phase of the takeoff roll when the FO (seated right) performs the takeoff.