A Saratov Airlines Antonov AN-148-100 that crashed while flying from Moscow to Orsk in February 2018 suffered from ice in the aircraft’s pitot tubes and erroneous actions of the crew, investigators have found.
Russia’s Interstate Aviation Committee (MAK) has handed down its final report into the February 11 2018 flight 6W 703 involving the AN-148-100 RA-61704.
All 65 passengers and six crew died in the incident.
While the final report was published in Russian, The Aviation Herald has translated portions of the report that relate to the probable cause of the accident.
The translation is reproduced here, with minimal editing:
The crash of the An-148-100B RA-61704 was caused by erroneous actions of the crew during departure in instrumental weather conditions in relation to unreliable indications of the air speed caused by the icing (ice blockage) of all three dynamic probes of the pitot system, which led to the loss of control over the parameters of the aircraft’s flight resulting in a dive and collision with the ground.
The accident falls into the category loss of control in flight (LOC-I).
The investigation revealed systemic deficiencies in the assessment of risk as well as risk control, the failure of the airline’s flight safety management system as well as lack of supervision of training of flight crew by aviation authorities at all levels, which led to the issuances of certificates to aviation personnel and crew, who did not fully qualify.
The most likely contributing factors were:
– Crew’s rush in preparation for the flight due to the late arrival of the aircraft from the previous flight and attempts to “catch up” time;
– The crew’s failure to turn on the heating of the pitot probes before take-off and non-compliance with/non-execution of the “BEFORE TAKEOFF” checklist, which provides for this action.
– Design features of the An-148 aircraft which restrict the duration of pitot heating while on the ground, which required to move the items pitot heating into the “BEFORE TAKEOFF” checklist rather than the “ENGINE START” checklist, which creates additional risks of missing these operations.
– Systematic failure by airline crews to comply with the principle of “dark cockpits” and the requirements of the pitot system, which contributed to the “habit” of taking off despite the presence of emergency and warning messages on the electronic indication and alarm system (KISS) and failing to identify the fact that the heating of the pitot probes is not included. Six warning messages were displayed on KISS before departure for the accident flight including three relating to the absence of pitot probes’ heating.
– Design features of the An-148 aircraft which disabled removal of KISS messages related to system defects which have been deferred under MEL.
– Low safety culture within the airline which led to non-entries of inflight problems into the tech logs as well as performing flights with issues that were neither rectified nor deferred with the relevant fault messages displayed at KISS and failure to identify the KISS messages and analyse them to identify lack of pitot probe heating.
– The crew’s unpreparedness when the ALARM “SPEED DISAGREE” was issued because of lack of theoretical training, lack of according simulator training and lack of according training on aircraft. This resulted in the failure to follow the proper procedures once the alarm was raised.
– Lack of supervision by the Civil Aviation Authority in certifying the flight simulator according to Russian Air Code
– Approval of the An-148 flight simulator without consideration to their ability to reproduce special cases in flight as stipulated in Russian Air Code and FAR-128.
– Lack of specific guidance on values of flight parameters that must be sustained in case of “SPEED DISAGREE” alarm respective lack of an unreliable airspeed procedure.
– Increased psycho-emotional stress by flight crew members during the final stages of flight due to the inability to understand the speed fluctuations. As result the captain suffered “tunnel view” on his speed indications for speed control rather than considering all flight parameters.
– Insufficient training of flight crew with respect to human factors, cockpit resource management, threat management and error management.
– Individual psychological characteristics by both flight crew, for the captain reduction of intellectual and behavioural flexibility, fixation on own position and inability to hear prompts from the first officer, for the first officer problems in organisation and sequencing actions) which in the stressful situation with inadequate CRM became apparent.
– Loss of psychological efficiency the captain (resulting on psychological incapacitation) which led to complete loss of spatial orientation and did not permit to respond properly to correct advice offered by the first officer or the EGPWS PULL UP warning.
– Absence of criteria to determine psychological incapacitation/loss of health which did not permit the first officer to take more efficient measures.
– Large arrear of annual leave that could have caused accumulation of fatigue and might have adversely affected the efficiency of the captain.
– System operations features not described in operations manual.
– Elevator control offset during reconfiguration mode with unreliable airspeed doubles elevator deflection with same control input and has the elevator deflected nose down with the control in neutral position for about 60 seconds which reduced time available to the crew to recognize the situation.
More information about the accident can be found on The Aviation Herald website.
VIDEO: Scenes at the Saratov Airlines crash site from Russia’s Ministry of Emergency Situations and published on The Aviation Herald’s YouTube channel.