By Simon Hradecky, created Wednesday, Apr 20th 2016 21:27Z, last updated Monday, May 16th 2016 13:32Z
In the late evening of Apr 20th 2016 The Interstate Aviation Committee (MAK) released their interim report in English stating, that following the first go around the crew entered a hold and subsequently requested to climb to FL150 after encountering moderate icing in the hold.
The second approach was flown manually in flight director mode (like the first approach), at 220 meters/720 feet of height and 4.5km/2.42nm before the runway threshold the crew decided to go around, one of the likely reasons being an air speed increase of 20 knots to 176 knots within 3 seconds. The engines were accelerated to 101/102% N1, maximum takeoff/go-around thrust. During the go around the crew retracted the landing gear and reduced the flaps to 15 degrees.
Climbing through 1900 feet AGL at nose up attitude of 18 degrees the pilot flying pushed the control column forward resulting in a nose down movement and reduction of vertical acceleration to +0.5G and an increase in airspeed causing the automatic retraction of flaps from 15 to 10 degrees at a speed of above 200 KIAS.
The engine thrust was reduced for a brief period resulting in a speed decrease, the flaps returned to 15 degrees, then engine thrust was increased again to TOGA, the flaps retracted automatically again to 10 degrees, the flaps remained in that position until impact.
The pilot flying applied nose up inputs resulting in a vertical climb rate of 16 meters/s (3150 fpm).
At a height of 900 meters/2950 feet a simultaneous nose down control input and a stabilizer nose down deflection from -2.5 degrees (6.5 units) to +2.5 degrees (1.5 units) occurred resulting in the aircraft, after having reached 1000 meters/3300 feet, to begin to descend and experience a vertical acceleration of -1.0G.
According to FDR the nose down trim input came from the stabilizer trim switch at the control column and lasted for 12 seconds while the cockpit voice recorder recorded specific noise of the trim wheels rotating.
The MAK wrote: "The following crew recovery actions did not allow to avoid an impact with the ground". The aircraft impacted the runway about 120 meters past the runway threshold with a speed of more than 600kph/324 knots and more than 50 degrees pitch nose down killing all occupants and destroying the aircraft.
The captain (ATPL) had accumulated 5,961 hours total and 4,905 hours on type, the first officer (ATPL) 5,767 hours total and 1,100 hours on type. The aircraft had accumulated 21,252 hours flying time in 9,420 flight cycles.
At the time of the accident ATIS (identification letter) E was active and read: "... surface wind 230 degrees, 12 mps gust 19 mps, visibility 3800 m, light shower rain, clouds scattered at 540 meters, broken cumulonimbus at 1080 m, moderate turbulence from surface to 1000 m; moderate icing in clouds at 900-1500 m, tempo wind 250 degrees 17 mps gust 25 mps, visibility 1000 m, shower rain, mist, clouds scattered cloudbase 90 m, broken cumulonimbus cludbase 600 m..."
Aerodrome ILS, outer and inner marker, runway lighting system and PAPIs were operating normally as per design.
The cockpit voice recorder is still being analysed and transcribed at the time of the release of the preliminary report.
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