Russian investigators have revealed that sloppy procedures and a poor safety culture pervaded Saratov Airlines before the fatal Antonov An-148 crash outside Moscow early last year.
The An-148 came down some 6min after take-off when – owing to the pilots' failure to activate the pitot-static heating system – all three of its pitot-static sensors became blocked with ice, generating unreliable airspeed information which overwhelmed the crew.
Flight 6W703 was behind schedule because the inbound service had been late, and the crew was rushing their preparations, the Interstate Aviation Committee states in its final conclusions over the 11 February 2018 crash.
Saratov Airlines had a "low safety culture", the inquiry says, and there was a systemic non-compliance by crews of the "dark cockpit" principle, in which instruments showed no warning indications.
This contributed to a "habitual" situation in which take-off would be conducted despite the presence of alerts on the central monitoring system, it adds, increasing the risk of their going unnoticed. When the An-148 departed Moscow Domodedovo it had six warnings displayed, including three about the absence of pitot heating.
The safety culture also allowed other slack practices to creep into its operations, notably the omission of recording failures detected during flight, and the performance of flights with unresolved defects.
Investigators found that the deficiencies in safety management led to weaknesses in identifying risks and a lack of control over the training of crew members, with some not fully satisfying qualification requirements.
The inquiry says the An-148 has a design feature restricting the duration of pitot-static heating while on the ground.
Saratov Airlines' deferred the pitot-static heating activation to the 'before take-off' checklist, but this created an "additional risk" of skipping this item, it states, considering that the crew was in a hurry.
When the unreliable airspeed alerts were triggered, shortly after departure, the crew was unprepared to deal with the situation owing to a lack of theoretical training from the airline and the inability to replicate the scenario on training equipment – with the result that the pilots did not follow the procedure in the flight operations manual.
The inquiry also says that the manual did not provide specific flight parameters – such as the engine mode, pitch, and angle-of-attack – to maintain in the event of such a development.
As a result the crew members were unable to understand the cause of the airspeed fluctuations and the captain reverted to a "tunnel" focus on his own indicators, failing to assess the aircraft's parameters comprehensively, a fixation which prevented his hearing prompts from the first officer.
This psychological incapacitation persisted to the point where spatial orientation was completely lost and the captain did not respond to 'pull up' alerts from the ground-proximity warning system, says the inquiry, while the first officer was left in a position of being unable to take "more decisive measures".
None of the 71 occupants of the An-148 survived when, having climbed to 2,000m, it entered a dive from which it failed to recover.
Investigators noted that the owing of "large debts" for annual leave could have led to an accumulation of fatigue and proven detrimental to the captain's abilities.