Landing (descent or approach)

The pilot decided to continue the approach in a flapless configuration and at an insufficient speed, which caused the aircraft to stall on short final.

The accident is attributable to the fact that on the final approach, in own navigation, of the standard VOR/DME approach 28 the aircraft flew controlled into a wooded range of hills (controlled flight into terrain – CFIT), because the flight crew deliberately continued the descent under instrument flight conditions below the minimum altitude for the approach without having the necessary prerequisites. The flight crew initiated the go around too late.
The investigation has determined the following causal factors in relation to the accident:
• The commander deliberately descended below the minimum descent altitude (MDA) of the standard VOR/DME approach 28 without having the required visual contact to the approach lights or the runway.
• The copilot made no attempt to prevent the continuation of the flight below the minimum descent altitude.
The following factors contributed to the accident:
• In the approach sector of runway 28 at Zurich airport there was no system available which triggers an alarm if a minimum safe altitude is violated (minimum safe altitude warning – MSAW).
• Over a long period of time, the responsible persons of the airline did not make correct assessments of the commander’s flying performance. Where weaknesses were perceptible, they did not take appropriate measures.
• The commander’s ability to concentrate and take appropriate decisions as well as his ability to analyse complex processes were adversely affected by fatigue.
• Task-sharing between the flight crew during the approach was not appropriate and did not correspond to the required procedures by the airline.
• The range of hills which the aircraft came into contact with was not marked on the approach chart used by the flight crew.
• The means of determining the meteorological visibility at the airport was not representative for the approach sector runway 28, because it did not correspond to the actual visibility.
• The valid visual minimums at the time of the accident were inappropriate for a decision to use the standard VOR/DME approach 28.

The accident was the consequence of an incorrect assessment of the situation by the commander of the aircraft during the approach, which resulted in errors in the piloting techniques, expressed in:
- Transition from intense icing conditions to active descent with a transition from the originally planned instrument approach to a visual approach;
- Failure to take into account the possibility of complex meteorological conditions in preparation for the approach and during the approach - the crew did not consider the possibility of going around or returning to the point of departure;
- Maintaining an unjustified low airspeed and high vertical descent speed during an approach with poor altitude control;
Associated factors were:
- Difficult weather conditions due to severe icing conditions;
- Reassessment by the aircraft commander of his knowledge and experience in controlling the An-28 aircraft in adverse weather conditions;
- Failure to comply with the requirements of the Airplane Flight Manual of the An-28 aircraft for the operation of aircraft systems and crew resource management;
- Failure to comply with the Airplane Flight Manual in terms of timely termination of the approach and transition to climb;
- The copilot, taking into account the large flying experience of the aircraft commander and overestimating his flight and navigation skills, behaved passively and did not provide him with adequate assistance in difficult conditions during the approach;
- Transition from an instrument approach to a visual approach without ATC clearance;
- The lack of 32 visual assessment of the angle of the descent trajectory (PAPI system) on the runway.

No technical anomalies were found on both engines. The fuel selector was positioned on the auxiliary tanks who had sufficient fuel at the time of the accident. It was reported that the pilot elected to continue the approach on one engine, letting himself be carried away by the luck factor that he benefited in the past in other similar situations.

It was reported that white smoke was coming out from the left engine during the descent, forcing the crew to shut it down and feathering its propeller. Due to lack of evidences because the wreckage was not found, the exact cause of the engine failure could not be determined.

The pilot's failure to discontinue the approach after encountering instrument meteorological conditions, which resulted in controlled flight into terrain. Contributing factors were the dark night light condition, low ceiling, and reduced visibility due to fog.

The inadequate planning/decision and the exceeded crosswind component by the pilot. The gusts were a contributing factor.

The captain's continued descent below the minimum descent altitude which resulted in impact with terrain during an instrument landing approach. Factors contributing to the accident were the flightcrew's failure to reset the altimeters to the correct altimeter setting, and meteorological conditions consisting of snow obscuration that limited visibility, and the ambient night light conditions.