What happened
On January 11, 2011, at approximately 15:28 UTC, a Robin DR 40/180R, registration I-ITAV, was performing a glider towing operation at Guidonia Airport, Italy. The aircraft was towing an ASK 21 glider, registration I-IVWJ, which carried a flight instructor and a student pilot.
Shortly after takeoff from runway 18, witnesses observed the tow plane suddenly change its flight attitude. At an altitude of only about 25 to 30 meters, the I-ITAV pitched downward and struck the runway surface. The impact caused the aircraft's fuel tanks to rupture, resulting in a violent collision and a subsequent intense fire that destroyed the aircraft. Although emergency responders from the Italian Air Force arrived quickly and extinguished the flames, the pilot of the I-ITAV died shortly after being extracted from the wreckage. The glider, which was able to complete a low-altitude turn and land safely on runway 36, remained undamaged, and the two occupants on board were uninjured.
The investigation
The ANSV investigation examined the flight history, aircraft maintenance records, and environmental conditions. The investigation confirmed that both aircraft were in a valid state of airworthiness and had been properly maintained. The crew of the tow plane and the occupants of the glider held valid licenses and medical certificates for their respective roles.
Investigators also analyzed the towing equipment, specifically the tow rope. While the rope's strength appeared consistent with required limits, the investigation noted that the rope lacked a "weak link" (a predetermined breaking point). Furthermore, the investigation looked into the meteorological conditions, noting that rain was present at the time of the accident, which had resulted in wet wings on both aircraft.
Findings
- The primary cause of the accident was human error, specifically the inability of the student pilot in the ASK 21 to maintain the correct flight attitude during the tow, which the instructor failed to correct promptly.
- The sudden change in the glider's attitude caused the tow plane to pitch down into the runway at a very low altitude.
- The tow rope used during the operation did not feature a "weak link," a safety component designed to prevent excessive loads.
- Rain during the operation resulted in wet wing surfaces, which can degrade aerodynamic performance.
- There was a lack of awareness regarding the importance of using certified breaking links in towing ropes.