What happened
On August 10, 2014, a Grob G103 Twin III Acro glider, registration I-IVVO, was performing a local flight for basic aerobatic maneuvers near Tassignano, Italy. The flight, which began following a tow by a Robin DR400/180R, proceeded normally until the aircraft entered the aerobatic box.
During the maneuvers, the glider's right wing separated from the fuselage. The loss of structural integrity rendered the aircraft uncontrollable. The pilot and a passenger, both of whom were glider pilots, attempted to exit the aircraft and deploy personal parachutes, but both individuals subsequently lost their lives. The right wing struck a private garden, while the fuselage and remaining left wing impacted a field approximately 650 meters away. There were no injuries to persons on the ground.
The investigation
The ANSV investigation examined the aircraft's maintenance history, the flight conditions, and the structural failure. The investigation found that the aircraft's documentation and maintenance schedules were up to date, and no manufacturing defects or improper repairs were identified in the composite structures.
Investigators analyzed the flight parameters and determined that the aircraft was operating at speeds near its maximum allowable limit (Vne). The investigation also reviewed the qualifications of the occupants, noting that while the pilot had limited experience, the passenger was an experienced aerobatic specialist, though he was not officially rated as an instructor despite being recorded as such in the club's flight logs.
Findings
- The primary cause of the accident was the separation of the right wing due to structural loads exceeding the aircraft's design limits.
- This structural failure was triggered by a sudden, aggressive pull-up maneuver performed from a heavily nose-down attitude while the aircraft was traveling at a speed near its maximum velocity (Vne).
- The pilot had relatively limited flight experience on gliders.
- Post-mortem examinations revealed that the pilot died from the impact, while the passenger had significant coronary artery disease, which may have influenced the management of the emergency.
- A regulatory gap was identified regarding the specific requirements for glider aerobatic endorsements in the national framework at the time of the accident.