Skydiving / Paratroopers

The pilot's failure to maintain adequate airspeed and use the appropriate flaps setting during sport-parachuting operations, which resulted in an aerodynamic stall/spin and a subsequent loss of control. Contributing to the accident was the pilot’s failure to follow company guidance by allowing more than four passengers in the door area during exit, which shifted the airplane’s center of gravity aft.

Whenever this aircraft is doing a short-field takeoff with a high weight, it is recommended that the flaps be set to their takeoff position of 20°. The evidence indicates that the pilot was attempting to take off on runway 27 and forgot to place the flaps in the takeoff position (20°).

The connecting rod in the second cylinder failed during initial climb, causing the engine to stop. The authorization to operate skydiving flights was canceled 21 April 2012.

According to the findings of the commission of inquiry, the most likely cause of the crash was the impact of the aircraft in a low-altitude wind due to strong downward air flow (micro-burst) during the landing of the aircraft in thunderstorms due to coincidence of the following negative factors.
- Failure of the crew to perform a go around or divert to the alternate aerodrome;
- A rapid increase in the speed of movement of the thunderstorm in the direction of the Borodyanka airfield area;
- Lack of training on the simulator in the conditions of wind shear, lack of experience in the crew on approach to landing in the conditions of wind shear, in particular micro-burst;
- Insufficient aeronautical equipment (lack of meteorological radar on the plane and airfield);
- Lack of information for the crew about the forecasted and actual meteorological conditions at the landing aerodrome, warnings about the forecasted / available wind shift at Borodyanka aerodrome;
- The crew was not sufficiently informed about the flight conditions due to insufficient lighting of the cockpit and failure of the instrumentation of the aircraft due to a power failure during approach in thunderstorm conditions;
- Lack of sufficient experience of the crew to perform activities and landings in conditions when the landing weight exceeded the maximum allowable, due to the presence of skydivers on board the aircraft;
- Motivation of the crew to perform the landing approach on the first attempt, due to insufficient information about the storm at the aerodrome. The information on wind increase and its direction (provided to the pilot) was perceived by the crew as possible conditions for landing because their parameters did not exceed the limits allowed by the AOM of the aircraft;
- Overloading of the aircraft, motivation of the decision of the captain to perform landing at the aerodrome of departure (Borodyanka) due to the presence of unregistered passengers on board, due to improper organization of boarding of skydivers at the aerodrome Borodyanka;
- Insufficient organization of flights at Borodyanka airfield in terms of meteorological support;
- Insufficient (weak) regulatory, regulatory, legislative framework for parachuting.

Investigation were unable to determine the cause of the turbine failure on final approach. Sufficient fuel (about 500 pounds) was still present in the tanks and all analysis of the engine, fuel supply control system and the fuel pump did not reveal any anomalies.

The pilot's failure to obtain a proper touchdown point, which resulted in a runway undershoot.

The aircraft was parked outside overnight prior to the accident and the windscreen, which had been covered, was clear of ice and frost when the cover was removed. Four hours after the accident, the windscreen was still clear, which suggested that ice and frost were not actively forming during that period. However, since frost was found on the upper surface of the wing, it was concluded that the frost would have been present prior to and during the takeoff. The maximum engine power was found to be approximately 50 bhp less than the rated value. This was attributed to the state of wear expected of an engine approximately 75% through its normal overhaul life rather than as a result of a failure experienced on this particular takeoff. The distance to lift off, calculated using the manufacturer’s performance information, should have been between 340 m and approximately 368 m and yet the aircraft actually left the ground after approximately 560 m. The extra distance used by the aircraft was probably a combination of two factors: the engine was not producing the power assumed in the performance calculation and the aircraft was rotated approximately three to five knots above VR. It is possible that takeoff performance was reduced due to the effects of frost on the wings but it was not possible to quantify these effects. As the aircraft began its left turn, the flaps were at FULL and yet the flap selector handle and the flaps were found in the TAKEOFF position following the accident. At some point in the turn, therefore, the flaps were raised by one stage. This would have had the effect of increasing the stalling speed by approximately three knots (in the case of an uncontaminated wing). The groundspeed of the aircraft, recorded by the GPS approximately six seconds before impact, was 58 kt. The aircraft was turning into a light wind and so the IAS might have been slightly higher. The stalling speed of the aircraft during the turn, with the flaps in the TAKEOFF position and with an uncontaminated wing, would have been approximately 63 kt. The effect of the frost would have been to increase the stalling speed, in the worst case, to 75 kt. The CAA Safety Sense Leaflet 3 suggests that the maximum reduction of lift might occur with frost that has a surface roughness of course sandpaper, whereas the frost found on G-CDYA was similar to medium sandpaper. Nevertheless, it was clear that the lifting ability of the wing would have been compromised and the stalling speed would have been higher than 63 kt. It seemed probable, therefore, that the aircraft stalled in the turn as a result of frost on the wing. Furthermore, the angle of attack at the stall was probably lower than that required to activate the stall warning horn.

The exact cause of the accident could not be determined.