Here's what MAK published today, translated by Google and polished with the help of my very deficient Russian, English and aviation knowledge. Any corrections are welcome.
Original here:
MAK: Yak-42 RA-42434
- Takeoff weight and center of gravity aircraft did not exceed the permissible limits
- Before take-off flaps were set at 20 degrees (take-off position), the stabilizer -8.7 degrees pitch up, which corresponds to estimated 24-25% of the alignment of the MAR (?)
- Before take-off the crew double-checked all channels of control of the aircraft, including the channel of the elevator, the elevator was deflected cleanly. The maximum recorded deflection of the elevator pitch up was 21 degrees, which corresponds to a constructive stop. Last check was performed 1 minute and 40 seconds before takeoff.
- Weather conditions at the time of the accident: wind 360 - 3 m/s, visibility 10 km, clouds significant stratocumulus lower limit of 990 m, the temperature +17.8° C, 747.9 mm Hg pressure. Art., friction coefficient of 0.6.
- Take-off from runway 23 was carried out. Taxiing aircraft to take-off was carried out by RD (taxiway?) 5. Distance from RD 5 to the start of runway 23: about 300 meters. Total runway length: 3000 meters.
- The crew decided to take off at nominal thrust settings. Preliminary simulations showed that the rate of up to ~ 165 km/h acceleration rate corresponded to the set engine thrust.
- Command to rise of nose wheel began at approximately 185 km/h. The elevator was set to pitch up at values of 9-10 degrees (about half way), but increase of pitch angle did not happen. After 6 seconds thrust settings were put in take-off mode. Despite increases take-off thrust, acceleration slowed significantly, which may be explained by the appearance of additional braking force. The actual value of an additional braking force will be established based on the results of mathematical modeling and field experiment. The braking systems of the aircraft were sent to be studied by a specialized institute. These study started on 16 September.
- The maximum speed reached by the plane: approximately 230 km/h. In spite of continuing increase of elevator pitch up, separation from the runway did not happen. According to the traces on scene (?), the actual separation of aircraft took place at a distance of 400 meters after exiting runway 23 end at deflection of elevator at 13-14 degrees and the relocation of the stabilizer to 9.5 degrees pitch up. After separation of the aircraft from the ground followed an encounter with the antenna system localizer and the rapid growth of the pitch angle to 20 degrees for 2-3 seconds. Maximum recorded height: 5-6 meters.
- Then followed an intensive roll of the plane to the left and its collision with obstacles and the ground.
- Measurements of fragments of the aircraft revealed that at the time of the accident flaps and slats were set in take-off position, the spoilers were retracted, the stabilizer in position about 10 degrees pitch up. Wiring layout elevator control showed that at the time of the accident there was not disconnection of wiring.
- The Technical Commission investigates all possible versions of occurrence of additional braking force during take-off and the reasons why the aircraft failed to make timely detachment from the runway.