United Aircraft has emphasised that the inquiry into a bounced landing, leading to a fatal fire which destroyed an Aeroflot Superjet 100, has found no faults with the aircraft design.
But the Russian Interstate Aviation Committee’s long-running investigation into the May 2019 accident at Moscow Sheremetyevo has nevertheless asked the airframer to consider a number of possible modifications to improve safety.
The aircraft landed heavily after its captain – experiencing difficulty controlling the jet in direct law – made heavy-handed pitch-control inputs during the touchdown. It bounced, and its landing-gear collapsed, rupturing fuel tanks and triggering a fatal fuel fire.
United Aircraft says the inquiry “did not find any design flaws” that would prohibit operation, adding that it carefully analysed certification matters and regulatory compliance.
“The cause of the accident was the human factor,” the aerospace firm states.
It supported the inquiry with tests and studies aimed at determining the circumstances behind the accident, which resulted in 41 fatalities.
The inquiry has requested that the aircraft developer “consider the feasibility” of amending the landing-gear design or introducing other measures to reduce fuel spillage in the event of an undercarriage collapse.
This assessment should also use international criteria to determine how much spilled fuel would constitute a fire hazard.
United Aircraft should also consider whether reducing the probability of the aircraft’s switching to direct flight-control law – or enabling restoration of normal law – is possible. The Aeroflot jet changed to direct law after encountering “atmospheric electricity”, the inquiry states.
Its recommendations to the manufacturer include analysing crew capabilities to handle multiple failure messages during flight, such as might be generated by system reboots, and possibly reducing their number.
United Aircraft says it has “accepted the recommendations” of the investigators.
Operators of the Superjet 100 have been advised by the investigators to conduct – with the aircraft developer – additional training on specific piloting issues under direct law, with “special attention” to manual pitch trimming and techniques during flare and landing.
Carriers should look at increasing the quantity of simulator training undertaken in direct law during all stages of flight, including go-arounds – not just for the Superjet but other aircraft types – and conduct a statistical analysis of performance by their Superjet pilots during take-off, flare and touchdown.
