What happened
On 6 July 2023, a Robinson R44 II helicopter, registration OK-LUK, was performing a PPL(H) training flight at the Warsaw-Babice aerodrome (EPBC). The flight was being conducted by GSA Aviation Sp. z o.o. for the purpose of spot hovering practice.
During the takeoff attempt at approximately 15:17, the helicopter began to rotate to the right by about 30 degrees while remaining in contact with the helipad. This was followed by a rapid rotation to the left around the vertical axis, spanning more than two full 360-degree turns. The movement was characterized by a 'cradle-like' motion, where the aircraft alternately struck the asphalt with the front and rear of the skids. During the second rotation, the tail boom struck the ground three times. The instructor-pilot eventually intervened to stop the rotation and subsequently shut down the engine. The crew members exited the aircraft without injury, but the helicopter sustained severe damage.
The investigation
The PKBWL investigation examined the aircraft's mechanical condition, specifically focusing on the hydraulic system. Technical expertise provided by the NTSB included testing of the three hydraulic amplifiers, which confirmed they were fully compliant with manufacturer parameters. The investigation also reviewed the aircraft's maintenance and airworthiness records. While the aircraft was found to be structurally intact and airworthy prior to the event, the investigation noted that continuing airworthiness records were maintained carelessly and contained numerous errors. Additionally, it was noted that the operator failed to notify the aerodrome operator of the occurrence.
Findings
- The primary cause of the loss of control was the inadequate coordination of the student-pilot's actions, specifically the improper correlation between the speed of the collective pitch lever movement and the use of the foot controls during takeoff.
- The instructor-pilot's reaction to the student-pilot's error was delayed.
- No mechanical malfunctions or failures in the hydraulic system or tail rotor control contributed to the accident.
- Meteorological conditions were favorable and did not affect the flight.
- The aircraft was within weight and center of gravity limits, and the fuel was uncontaminated.