What happened
On March 4, 2021, at approximately 12:20 UTC, a Z-37A agricultural aircraft, registration OK-ZKB, was performing crop dusting operations near Ježov, Czech Republic. After completing several successful working flights that day, the pilot initiated a takeoff from a working area.
While the aircraft initially climbed normally after rotation, the pilot observed that the aircraft was not performing as expected. At an extremely low altitude of approximately 1.5 to 2 meters, the aircraft began to deviate to the left and lose both airspeed and altitude. Despite the pilot applying full rudder input, the leftward deviation continued.
In an attempt to manage the situation, the pilot activated the agricultural spreading equipment to jettison the load, but refrained from a full emergency release to avoid the spreader hitting the control surfaces at such a low height. The aircraft's left main landing gear subsequently struck the ground, followed by the right gear, which caused the landing gear leg to break. The aircraft then slid sideways across the soft terrain. During the sequence, the propeller struck the ground, and the spreader assembly was torn from the airframe. The pilot successfully exited the aircraft uninjured.
The investigation
The ÚZPLN investigation examined the aircraft's maintenance history, the pilot's qualifications, and the meteorological conditions. The aircraft had undergone its most recent periodic inspection in December 2020, and no defects were noted by the pilot or mechanic during the preceding days of operation. The aircraft's takeoff weight was approximately 1,735 kg, which was within the maximum allowable limit of 1,850 kg.
Investigators also reviewed meteorological data from the Czech Hydrometeorological Institute. While another pilot in the area reported experiencing a strong thermal gust during a nearby flight, the official meteorological analysis did not show a high probability of significant weather changes or extreme turbulence that could have definitively caused the deviation.
Findings
- The pilot was highly experienced in agricultural flight operations on this aircraft type.
- The aircraft was airworthy, and no mechanical failures were identified that could have contributed to the accident.
- The pilot experienced a sudden change in flight characteristics, including a loss of airspeed and a persistent leftward turn that could not be corrected with rudder input.
- The primary cause of the accident was the loss of control during takeoff, characterized by the aircraft deviating from its path and losing altitude very low to the ground.
- It is considered possible that the aircraft was affected by a strong thermal gust during the critical phase of takeoff.