What happened
On March 27, 2009, a Discus 2B glider, registration D-7764, was performing a takeoff at Alzate Brianza Airport, following a Robin DR400/180R aircraft, registration I-ITAF. During the takeoff roll, the pilot of the towing aircraft noticed via the rearview mirror that the glider was maintaining a very nose-down attitude. To avoid a dangerous situation, the tow pilot maintained a level flight at approximately one meter above the runway while waiting for the glider to rotate.
As the tow aircraft approached the end of the runway and began a slight climb, the pilot felt a constant downward and leftward pull on the tail. Fearing a mechanical failure or loss of control, the tow pilot activated the cable release. The glider pilot, realizing they were flying too low and that the cable tension was abnormal, also attempted to release the cable, but the tow aircraft had already completed the maneuver, leaving the cable attached only to the glider side.
After the release, the glider climbed to approximately 50 meters. Following instructions from ground personnel, the pilot attempted to fly toward a group of tall trees located beyond the southern end of the runway. The pilot performed a sharp pitch-up maneuver to avoid the treetops, causing the glider's tail boom to strike the trees. The glider came to rest balanced in the trees at an altitude of about 10 meters. The pilot was uninjured, but the Discus 2B suffered extensive structural damage, including a torn right wing leading edge, a destroyed canopy, and a complete failure of the tail boom.
The investigation
The ANSV investigation focused on the flight dynamics and the pilot's experience. The investigation confirmed that the glider was airworthy and that all relevant Airworthiness Directives, including those regarding elevator trim weights, had been implemented.
Investigators noted that the pilot was performing a "passaggio macchina" (transitioning to a new aircraft type) and possessed limited experience, with fewer than 10 flight hours since obtaining their license and very limited time in single-seat gliders. The investigation also reviewed the standard operating procedures of the Aero Club Volovelistico Lariano, which dictated that for releases occurring after the two-thirds mark of the runway at low altitude, the pilot should continue straight beyond the runway threshold.
Findings
- The primary cause of the incident was the incorrect pitch attitude maintained by the glider pilot during the takeoff roll, which prevented the glider from following the tow aircraft's ascent.
- This improper attitude prompted the tow pilot to execute an emergency cable release to prevent loss of control of the lead aircraft.
- The pilot's limited flight experience and lack of familiarity with this specific aircraft type contributed to the error.