Russian authorities have warned over the potential hazard from insufficient runway preparation after a landing incident at Ulyanovsk involving a Sukhoi Superjet 100.
The Aeroflot aircraft (RA-89032) had conducted its approach to Baratayevka airport at night on 25 March, touching down on runway 21 which was affected by snowfall.
As the Superjet rolled out, the crew noticed in the aircraft’s lights that a 40-45cm high ridge of snow was present on the left of the runway centreline.
“For the first time in my life I’ve seen this,” one of the pilots told the air traffic controller.
The captain stated that, during the roll-out, the crew struggled to retain directional control owing to the difference in snow cover beneath the left- and right-hand main landing-gear.
To maintain the runway heading, in a 10kt wind from the north, required right rudder deflection to 20.9° – compared with a maximum 27.6° – and the use of differential braking.
Russia’s federal air transport regulator Rosaviatsia states that the inquiry found the runway had been swept with a single vehicle 10min before the landing, but that the co-efficient of friction was not measured.
Baratayevka airport’s weather service had been transmitting that the runway was more than half-coated in a 3mm layer of sleet, with a friction co-efficient of 0.39.
“The presence of the snow ridge may indicate that quality control of the runway sweeping was not carried out,” says Rosaviatsia. Thirty minutes after the landing the co-efficients of friction were found to vary between 0.08 and 0.1.
Rosaviatsia points out that “poor-quality” runway operations at the same airport had led to a serious incident on roll-out involving a Utair ATR 72-500 in April 2015.
The investigation found the 60m-wide runway, with 5mm of slush, was “not prepared to receive the aircraft”, having been cleared only 10m either side of the centreline – with slush layers up to 50mm on the uncleared areas.
Rosaviatsia says this “repetition of violations” in airfield preparation indicates that implementation of safety-management principles by airport operators is “low” and progress in this crucial activity is “insufficient”.
It lists an incident in October 2015 at Magas airport, in southern Russian, during which a Pobeda Boeing 737-800 landed on an “unprepared” runway which had been cleared only to 5-10m from the centreline, with piled snow remaining.
Rosaviatsia also highlights the February 2014 accident involving an East Air Airbus A320 which sustained damage to its landing-gear after colliding with snow banks 50-95cm high at Kulob in Tajikistan.