What happened
On January 10, 2020, a Schweizer 269-C helicopter, registration LV-AFB, was participating in a general aviation flight instruction mission at the Casilda Aerodrome in Santa Fe. Following a one-hour instructional flight, the crew intended to land near the aerodrome's fixed fuel station to prepare for a subsequent flight.
During the landing phase, while taxiing at a low altitude of approximately 20 centimeters above the ground, the aircraft experienced a sudden loss of directional control. The helicopter underwent a 180-degree turn to the right, leading to a dynamic rollover. The impact of the main rotor blades with the ground caused significant damage to the rotor system and the tail rotor, eventually leaving the aircraft overturned on its right side. There were no injuries to the instructor or the student pilot.
The investigation
Investigators examined the wreckage and the surrounding terrain to reconstruct the sequence of events. The investigation found that the main rotor blades were deformed by ground impact and the tail rotor had become detached. While the cyclic and collective control systems showed no mechanical failures, the main rotor blade articulation elements were broken.
Physical evidence on the ground, including a patch of uprooted grass and skid marks, indicated that the right skid had made contact with the terrain. The investigation analyzed the proximity of the aircraft to the fuel station, noting that the 8.178-meter rotor diameter necessitated a close approach to utilize the 10-meter fueling hose. The investigators also evaluated the distinction between static and dynamic rollover, concluding that the evidence supported a dynamic rollover caused by the aircraft pivoting on a point of contact with the ground during lateral movement.
Findings
- The pilot experienced a momentary loss of directional control due to the right landing skid making contact with the ground.
- Recovery efforts following the initial loss of control were ineffective, leading to the dynamic rollover.
- The chosen landing location was in close proximity to a fixed structure, which necessitated the presence of a qualified signal person according to regulations.
- The operation was conducted without a signal person, a practice that had become regular for this type of maneuver at the aerodrome.
- The incident occurred within a context of unobserved operational safety deficiencies at the facility.