Kazakh carrier Bek Air has disclosed details of the in-flight upset which affected the Fokker 100 which crashed on take-off from Almaty on 27 December.

Bek Air states that the aircraft’s airframe and engine de-icing systems had been activated, and that the jet departed with zero flap extension. Zero flap is a normal available take-off setting for Fokker 100s.

The aircraft accelerated along runway 05R, from which it was conducting a full-length take-off roll, and became airborne at 07:20:36 at a speed of 148kt.

Bek Air adds that the aircraft’s Rolls-Royce Tay engines and other systems were functioning normally with no anomalies evident.

The carrier has not stated whether the aircraft underwent an external de-icing process before departure.

As the aircraft lifted off, it immediately started oscillating, apparently initially to the left before rolling sharply 18.7° to the right, then 14.5° left, then 10.9° right.

While the inquiry has yet to reach any conclusions, similar oscillations on take-off have previously been recorded in Fokker 100s whose wing lift has been impaired by ice contamination.

Over the course of the flight, which lasted just 36s, the aircraft never exceeded 20ft in height, according to the airline’s data.

After only 10s or so, the aircraft lost height completely, travelling virtually along the ground – but with a nose-up attitude of some 12-13° – for around 15s. The data, which has not been independently verified, indicates the landing-gear was retracted 30s after take-off, about 6s before the jet collided with obstacles.

Bek Air F100

Source: Bek Air

Bek Air insists the ill-fated Fokker 100 had been properly maintained

The Fokker 100 involved in the accident (UP-F1007) had accumulated 52,771 cycles, the carrier states. Its captain had logged over 21,000h including more than 4,000 in command of Fokker 100s. The first officer had 5,000h on type out of 11,500h in total.

Bek Air insists the aircraft, which it received from German operator Contact Air in 2013, had undergone all necessary maintenance “in strict accordance” with regulations, and had been released to flight in late October after C1, C2 and D2 checks.

Ulyanovsk-based Spektr-Avia repainted the aircraft following the maintenance work, the carrier adds.

Kazakhstan’s government has distanced itself from the Bek Air disclosures, stating that – in accordance with ICAO standards – official details of the inquiry are supposed to be given by the investigative commission. Russia’s Interstate Aviation Committee has been tasked with analysing the flight recorders, and has yet to reveal findings from the data.